tunable exciton binding energy in 2d hybrid layered perovskites …10.1038... · 2020-06-25 ·...

Articleshttps://doi.org/10.1038/s41557-020-0488-2

Tunable exciton binding energy in 2D hybrid layered perovskites through donor–acceptor interactions within the organic layerJames V. Passarelli 1,9, Catherine M. Mauck 2,8,9, Samuel W. Winslow 2, Collin F. Perkinson 3, Jacob C. Bard 1, Hiroaki Sai 4, Kristopher W. Williams2, Ashwin Narayanan4, Daniel J. Fairfield 5, Mark P. Hendricks 4, William A. Tisdale 2 ✉ and Samuel I. Stupp 1,4,5,6,7 ✉

1Department of Chemistry, Northwestern University, Evanston, IL, USA. 2Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA. 3Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA. 4Simpson Querrey Institute, Northwestern University, Chicago, IL, USA. 5Department of Materials Science and Engineering, Northwestern University, Evanston, IL, USA. 6Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA. 7Department of Medicine, Northwestern University, Chicago, IL, USA. 8Present address: Department of Chemistry, Kenyon College, Gambier, OH, USA. 9These authors contributed equally: James V. Passarelli, Catherine M. Mauck. ✉e-mail: [email protected]; [email protected]

SUPPLEMENTARY INFORMATION

In the format provided by the authors and unedited.

NATure CHeMISTry | www.nature.com/naturechemistry

http://orcid.org/0000-0001-7918-9392

http://orcid.org/0000-0002-6432-9724

http://orcid.org/0000-0003-2756-4132

http://orcid.org/0000-0002-5676-1998

http://orcid.org/0000-0002-8585-2653

http://orcid.org/0000-0002-4268-2148

http://orcid.org/0000-0001-5880-2055

http://orcid.org/0000-0003-1295-9879

http://orcid.org/0000-0002-6615-5342

http://orcid.org/0000-0002-5491-7442

mailto:[email protected]

mailto:[email protected]

http://www.nature.com/naturechemistry

1

Supporting Information for

Tunable exciton binding energy in 2D hybrid layered perovskites through donor–acceptor interactions

within the organic layer

James V. Passarelli†1, Catherine M. Mauck†2*, Samuel W. Winslow2, Collin F. Perkinson3, Jacob C. Bard,1 Hiroaki Sai4, Kristopher W. Williams,2 Ashwin Narayanan4,

Daniel J. Fairfield5, Mark P. Hendricks4, William A. Tisdale*,2, and Samuel I. Stupp*,1,4,5,6,7

1Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA. 2Department

of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts

02139, USA. 3Department of Chemistry, Massachusetts Institute of Technology, Cambridge,

Massachusetts 02143, USA. 4Simpson Querrey Institute, Northwestern University, Chicago,

Illinois 60611. 5Department of Materials Science and Engineering, Northwestern University,

Evanston, Illinois 60208, USA. 6Department of Biomedical Engineering, Northwestern University,

Evanston, IL 60208, USA. 7Department of Medicine, Northwestern University, Chicago, Illinois

60611, USA.

†These authors contributed equally to this work.

*Current affiliation: Department of Chemistry, Kenyon College, Gambier, OH 43022

Corresponding authors:

*[email protected]

*[email protected]

2

Table of Contents A. Synthesis

1. Organic molecule synthesis .......................................................................................... 4 i. Naphthalene-O-butyl-phthalimide (A)

ii. Naphthalene-O-butyl-NH3I (B) iii. Naphthalene-O-hexyl-pthalimide (C) iv. Naphthalene-O-hexyl-NH3I (D) v. MeO-naphthalene-O-ethyl-BOC (E)

vi. MeO-naphthalene-O-ethyl-NH3I (F) vii. MeO-naphthalene-O-butyl-Br (G)

viii. MeO-naphthalene-O-butyl-pthalimide (H) ix. MeO-naphthalene-O-butyl-NH3I (I) x. MeO-naphthalene-O-hexyl-Br (J)

xi. MeO-naphthalene-O-hexyl-pthalimide (K) xii. MeO-naphthalene-O-hexyl-NH3I (L)

xiii. Cl5-O-propyl-BOC (M) xiv. Cl5-O-propyl-NH3I (N)

2. Supplementary Table 1. Crystallographic details for n = 1 layered perovskites i. 3_H_Naphthalaene_Butyl_PbI4 (CCDC: 1934873)

ii. 4_H_Naphthalene_Hexyl_PbI4 (CCDC 1934874) iii. 5_MeO_Naphthalene_ethyl_PbI4 (CCDC 1934872) iv. 6_MeO_Naphthalene_butyl_PbI4 (CCDC 1934871) v. 7_MeO_Naphthalene_hexyl_PbI4 (CCDC 1934875)

vi. 8_Cl5_Ph_Propyl_PbI4 (CCDC 1934876)

B. Film preparation ...................................................................................................................... 14 1. X-Ray film characterization

i. Supplementary Figure 1 GIWAXS confirming crystal structure in thin film ii. Supplementary Figure 2 FWHM analysis demonstrating minimal change in domain size upon

TCBQ addition iii. Supplementary Figures 3-8 Off-axis reflections in GIWAXS demonstrating minimal to no

distortion of unit cell in-plane upon TCBQ addition 2. CT characterization

i. Supplementary Figure 9 Thin-film CT absorption spectra ii. Supplementary Figure 10 Insoluble CT complex that results from 1,4-chloranil and 1,4-

fluoranil iii. Supplementary Figure 11 NMR study demonstrating negligible reduction-oxidation of

precursor solution 3. SEM-EDS Cl:I ratio

i. Supplementary Figure 12 PXRD of films before and after TCBQ incorporation ii. Supplementary Figure 13 Optical micrographs of film fragments

iii. Supplementary Figures 14-16 SEM-EDS fits of spectra iv. Supplementary Table 2 including Note on Interpretation EDS analysis for Cl-I ratio

4. Annealing effects on 2 with 1 eq TCBQ i. Supplementary Figure 17 Optical and structural data from variable temperature annealing of 2

3

C. Optical and structural characterization ................................................................................... 29 1. PXRD and UV-Vis with ∆d and ∆E1s

i. Supplementary Figure 18 Compound 1 (naphthalene-O-ethyl-NH3+)2PbI4 ii. Supplementary Figure 19 Compound 5 (MeO-naphthalene-O-ethyl-NH3+)2PbI4

iii. Supplementary Figure 20 Compound 6 (MeO-naphthalene-O-butyl-NH3+)2PbI4 iv. Supplementary Figure 21 Compound 7 (MeO-naphthalene-O-hexyl-NH3+)2PbI4

2. Supplementary Figure 22 Formulation studies with butyl and hexylammonium lead iodide perovskite

3. Supplementary Figure 23 Addition of molecular iodine and tetrachlorocatechol to spin-coating solutions

4. Supplementary Figure 24 Change in d spacing vs change in E1s for 2, 5, 6, and 7

D. Structural discussion of TCBQ incorporation regimes ........................................................... 36 i. Structural dependence of dopant incorporation

ii. Supplementary Figure 25 Washing regime 1, showing layer expansion iii. Supplementary Figure 26 Washing regime 2, showing layer contraction iv. Supplementary Figure 27 Cation packing to differentiate regime 1 and 2 v. Supplementary Figure 28 Comparison of Van der Waals gap size

E. Photoluminescence spectroscopy ............................................................................................ 42

1. Supplementary Figure 29 PL at selected temperatures for 2 doped and undoped samples 2. Supplementary Figure 30 Film images displaying inhomogeneity and relationship to BE 3. Supplementary Figure 31 Single crystal PL showing FE band split 4. Supplementary Figure 32 Cryogenic PLE

F. Electronic absorption .............................................................................................................. 47

1. Discussion i. Supplementary Equations 1-7 and construction of modified 2D Elliott model

ii. Markov chain Monte Carlo (MCMC) method for fitting 2. Supplementary Figure 33 Sample low temperature absorption spectrum of compound 2 with

0 eq TCBQ with overlaid Elliott fit and individual fit components 3. Supplementary Figure 34. Effective dielectric constants and exciton peak energies from

Elliott fit of compound 2 with 0 eq TCBQ as a function of quantum number m 4. Supplementary Figure 35 Correlation corner plot at 8 K of selected MCMC fit parameters

G. Supplementary characterization data………………………………………………………………….52

1. 1H and 13C NMR 2. High resolution mass spectrometry 3. A and B level alerts from checkCif

4

A: SYNTHESIS

Synthesis: Organic molecule synthesis and molecular characterization

Materials and Methods: All starting materials were purchased from MilliporeSigma and all solvents from Fisher Chemical unless otherwise noted. Chromatography was performed using silica gel as the stationary phase.

NMR Characterization: NMR spectra (1H and 13C) where collected on a 500 MHz Bruker Avance III HD system with a TXO Prodigy Probe. Deuterated solvents (dimethyl sulfoxide and chloroform) were purchased from Sigma Aldrich and all chemical shifts are reported from spectra internally referenced to the solvent residual.

Mass Determination: High-resolution mass spectrometry was acquired using an Agilent 6210 LC-TOF high-resolution time of flight mass spectrometer with an Agilent 1200 series LC pump stack and Autosampler. Electrospray ionization was used in all cases.

The ammonium iodide salts napthylene-O-ethyl-NH3I and naphthalene-O-propyl-NH3I were synthesized according to previously reported methods.1 Additionally, 5-methoxynapthalene-1-ol was synthesized according to literature methods at 10X the reported scale.2

Nap-O-Bu-phthalimide (A): To a 250 mL round bottom flask fitted with a magnetic stir bar, 1-napthol (2 g, 13.9 mmol), N-(4-Bromobutyl)phthalimide (5.87 g, 20.8 mmol, ACROS Organics), and potassium carbonate (4.78 g, 34.7 mmol) were added. To this was added 100 mL of acetonitrile and the flask was heated in an oil bath at 65 °C overnight. The flask was then allowed to cool to room temperature and, under stirring, 150 mL of water was added. The resulting suspension was the poured into an additional 300 mL of water. The solid was filtered and dried on the frit. The resulting solid was chromatographed in 85:15 Hexanes: Ethyl acetate and the product collected and solvent removed to reveal a white solid (2 g, 42% yield) 1H NMR (500 MHz, Chloroform-d) δ 8.34 – 8.19 (m, 1H), 7.88 – 7.80 (m, 2H), 7.80 – 7.75 (m, 1H), 7.75 – 7.66 (m, 2H), 7.51 – 7.43 (m, 2H), 7.42 – 7.38 (m, 1H), 7.34 (dd, J = 8.3, 7.5 Hz, 1H), 6.79 (dd, J = 7.6, 1.1 Hz, 1H), 4.18 (t, 2H), 3.83 (t, 2H), 2.06 – 1.95 (m, 4H). 13C NMR (126 MHz, Chloroform-d) δ 168.49, 154.63, 134.48, 133.92, 132.13, 127.41, 126.35, 125.85, 125.66, 125.15, 123.23, 122.05, 120.16, 104.59, 67.29, 37.74, 26.74, 25.55.

HRMS (ESI-TOF) (M+Na)+ Expected 368.1257 Observed 368.1260

5

Nap-O-Bu-NH3I (B): To a 250 mL round bottom flask fitted with a magnetic stir bar was added 150 mL of ethanol and 1.8 g (5.2 mmol) of A. To this was added 3 g of hydrazine monohydrate. The reaction was stirred at 70 °C for 4hrs. The reaction was cooled to RT and ca. ½ of the ethanol was removed by rotary evaporation. To the resulting suspension, 100 mL of DCM was added and the mixture was filtered and the resulting solid washed with 50 mL of DCM twice. The filtrate was collected, and the solvent was removed by rotary evaporation to a solid. This solid was suspended in 100 mL DCM and filtered. The solid was washed 2X with DCM and the filtrate collected. This process was repeated one more time. The resulting oil recovered after rotary evaporation was precipitated with 100 mL water. The solid was filtered off and washed with a copious amount of water to remove residual hydrazine. This solid was then dissolved in 100 mL of dioxane and to this was added 1.28g (5.72 mmol) 57 wt% hydroiodic acid containing no stabilizer. The solvent was removed from the resulting solution to give a solid and this solid was first sonicated with diethyl ether and then transferred to a frit where it was washed with a copious amount of diethyl ether. The resulting white solid was then dried under vacuum for several days (1.01 g, 57% yield). 1H NMR (500 MHz, DMSO-d6) δ 8.17 (dd, J = 8.0, 1.6 Hz, 1H), 7.92 – 7.83 (m, 1H), 7.68 (s, 3H), 7.56 – 7.44 (m, 3H), 7.44 – 7.35 (m, 1H), 6.97 (dd, J = 7.6, 1.1 Hz, 1H), 4.19 (t, J = 6.0 Hz, 2H), 3.02 – 2.83 (m, 2H), 1.98 – 1.87 (m, 2H), 1.87 – 1.77 (m, 2H). 13C NMR (126 MHz, DMSO-d6) δ 153.91, 134.03, 127.52, 126.44, 126.26, 125.21, 124.88, 121.41, 119.89, 105.16, 67.08, 38.78, 25.73, 24.20.

HRMS (ESI-TOF) Expected 216.1383 Observed 216.1380

Nap-O-Hex-phthalimide (C): To a 250 mL round bottom flask fitted with a magnetic stir bar, 1-napthol (1.5 g, 10.4 mmol), N-(6-Bromohexyl)phthalimide (3.87 g, 12.5 mmol, TCI Chemicals), and added potassium carbonate (2.87 g, 20.8 mmol) were added. To this was added 75 mL of acetonitrile and the flask was heated in an oil bath at 65 °C overnight. The flask was then allowed to cool to room temperature and, under stirring, 150 mL of water was added. The resulting suspension was the poured into an additional 300 mL of water. The Solid was filtered and dried on the frit. The resulting solid was chromatographed in 85:15 hexanes:ethyl acetate and the product collected and the solvent removed by rotary evaporation to give a white solid (1.6 g, 34% yield) 1H NMR (500 MHz, Chloroform-d) δ 8.32 – 8.21 (m, 1H), 7.87 – 7.80 (m, 2H), 7.80 – 7.74 (m, 1H), 7.73 – 7.65 (m, 2H), 7.51 – 7.43 (m, 2H), 7.41 – 7.38 (m, 1H), 7.38 – 7.32 (m, 1H), 6.78 (dd, J = 7.5, 1.1 Hz, 1H), 4.13 (t, J = 6.3 Hz, 2H), 3.72 (t, J = 7.3 Hz, 2H), 1.98 – 1.89 (m, 2H), 1.83 – 1.72 (m, 2H), 1.70 – 1.58 (m, 2H), 1.54 – 1.43 (m, 2H). 13C NMR (126 MHz, Chloroform-d) δ

6

168.49, 154.82, 134.49, 133.86, 132.18, 127.39, 126.31, 125.89, 125.73, 125.09, 123.18, 122.09, 119.97, 104.51, 67.92, 37.97, 29.21, 28.60, 26.71, 25.96.


Nap-O-Hex-NH3I (D): To a 100 mL round bottom flask fitted with a magnetic stir bar was added 50 mL of ethanol and 0.85 g (2.27 mmol) of C. To this was added 1.5 g of hydrazine monohydrate. The reaction was stirred at 70 °C for 4 hrs. The reaction was cooled to RT and ca. ½ of the ethanol was removed by rotary evaporation. To the resulting suspension, 50 mL of DCM was added and the mixture was filtered and the resulting solid washed with 50 mL of DCM twice. The filtrate was collected and solvent removed by rotary evaporation to give a solid. This solid was suspended in 100 mL DCM and filtered. The solid was washed 2X with DCM and the filtrate collected. This process was repeated one more time. The resulting oil recovered after rotary evaporation and was precipitated with 100 mL water. The solid was filtered off and washed with a copious amount of water to remove residual hydrazine. This solid was then dissolved in 50 mL of dioxane and to this was added 0.56 g (2.5 mmol) 57 wt% hydroiodic acid containing no stabilizer. The solvent was removed from the resulting solution yielding a solid and this solid was first sonicated with diethyl ether and then transferred to a frit where it was washed with a copious amount of diethyl ether. The resulting white solid was then dried under vacuum for several days (0.52 g, 62% yield). 1H NMR (500 MHz, DMSO-d6) δ 8.15 (dd, J = 7.8, 1.6 Hz, 1H), 7.87 (dd, J = 7.7, 1.7 Hz, 1H), 7.60 (s, 3H), 7.55 – 7.44 (m, 3H), 7.44 – 7.38 (m, 1H), 6.96 (dd, J = 7.5, 1.1 Hz, 1H), 4.16 (t, J = 6.3 Hz, 2H), 2.85 – 2.74 (m, 2H), 1.93 – 1.80 (m, 2H), 1.66 – 1.50 (m, 4H), 1.48 – 1.37 (m, 2H). 13C NMR (126 MHz, DMSO-d6) δ 154.06, 134.03, 127.50, 126.41, 126.26, 125.23, 124.95, 121.40, 119.78, 105.10, 67.51, 38.83, 28.47, 26.96, 25.51, 25.23.


MeO-Nap-O-Et-BOC (E): 5-methoxynapthalene-1-ol and 2-(Boc-amino)ethyl bromide were synthesized according to previously reported methods.2 To a 100 mL RBF was added 1 g (5.75 mmol) of 5-methoxynapthalene-1-ol, 3.17 g (23 mmol) of potassium carbonate and 50 mL of acetonitrile. To this was added 2.18 g (9.8 mmol) of 2-(Boc-amino)ethyl bromide. The resulting reaction mixture was heated overnight at 65 °C. The reaction was then allowed to cool and 50 mL of water was then added to the reaction mixture. The entire contents of the RBF were then poured into 500 mL of water. The resulting solid was recovered by filtration. Once this solid was dry it

7

was chromatographed on silica gel with 75:25 hexanes: ethyl acetate. The product was recovered by rotary evaporation (0.97 g, 26% yield). 1H NMR (500 MHz, Chloroform-d) δ 7.88 – 7.80 (m, 2H), 7.37 (ddd, J = 15.1, 8.5, 7.6 Hz, 2H), 6.85 (ddd, J = 11.7, 7.6, 0.9 Hz, 2H), 5.04 (s, 1H), 4.19 (t, J = 5.1 Hz, 2H), 4.00 (s, 3H), 3.68 (q, J = 5.4 Hz, 2H), 1.46 (s, 9H). 13C NMR (126 MHz, Chloroform-d) δ 155.9, 155.30, 154.08, 126.67, 126.50, 125.27, 125.14, 114.66, 114.05, 105.56, 104.58, 79.58, 67.60, 55.57, 40.26, 28.42.

MeO-Nap-O-Et-NH3I (F) To a 50 mL RBF with a magnetic stir bar was added 0.85 g (2.46 mmol) of E and 25 mL of dioxane. To this was added 2.95 g (13.1 mmol) of 57% hydroiodic acid containing no stabilizer. The reaction was stirred at 50 °C for 1 hr. The resulting solution was then evaporated to a solid. This solid was then suspended in diethyl ether and sonicated. The solid was then recovered by filtration and washed with a copious amount of diethyl ether. The resulting white solid was dried under vacuum for several days (0.78 g, 92% yield). 1H NMR (500 MHz, DMSO-d6) δ 8.02 (s, 3H), 7.99 (dt, J = 8.5, 0.9 Hz, 1H), 7.75 (dt, J = 8.5, 0.9 Hz, 1H), 7.47 – 7.37 (m, 2H), 7.07 – 6.98 (m, 2H), 4.32 (dd, J = 5.5, 4.4 Hz, 2H), 3.96 (s, 3H), 3.42 – 3.35 (m, 2H). 13C NMR (126 MHz, DMSO-d6) δ 154.55, 153.36, 125.82, 125.75, 125.38, 125.37, 114.40, 114.25, 105.96, 105.12, 64.61, 55.59, 38.54.


MeO-Nap-O-Bu-Br (G): To a 250 mL round bottom flask fitted with a magnetic stir bar, 5-methoxynapthalene-1-ol (2 g, 11.5 mmol), and potassium carbonate (4.76 g, 34.5 mmol) were added. To this was added 75 mL of acetonitrile then 14.8 g of 1,4-dibromobutane (68 mmol), and the flask was heated in an oil bath at 65 °C overnight. The flask was then allowed to cool to room temperature and the solvent removed by rotary evaporation. Water was added to the resulting material and extracted with DCM three times. The combined organic extractions were extracted once with saturated NaCl and dried with anhydrous MgSO4 then concentrated by rotary evaporation. The resulting residue was chromatographed in 80:20 hexanes:dichloromethane. The product was collected, and the solvent removed by rotary evaporation to give a white solid (1.98 g, 56% yield)

8

1H NMR (500 MHz, Chloroform-d) δ 7.84 (dd, J = 8.6, 0.9 Hz, 2H), 7.42 – 7.31 (m, 2H), 6.90 – 6.79 (m, 2H), 4.17 (t, J = 5.9 Hz, 2H), 4.00 (s, 3H), 3.55 (t, J = 6.5 Hz, 2H), 2.25 – 2.14 (m, 2H), 2.14 – 2.05 (m, 2H). 13C NMR (126 MHz, Chloroform-d) δ 155.27, 154.40, 126.66, 125.19, 125.16, 114.26, 114.17, 105.33, 104.54, 67.04, 55.56, 33.61, 29.74, 27.95.

MeO-Nap-O-Bu-phthalimide (H): To a 100 mL RBF fitted with a magnetic stir bar, G (1.8 g, 5.82 mmol), and potassium phthalimide (2.15 g, 11.6 mmol) were added. To this, 50 mL of DMF were added and the flask heated in an oil bath at 120 °C overnight. The reaction was allowed to cool and much of the DMF was removed by rotary evaporation. The resulting oil was precipitated in water and the precipitate recovered by filtration. The crude dry powder was chromatographed in 70:30 hexanes:ethyl acetate. The product was collected, and the solvent removed by rotary evaporation to give a white solid (1.01 g, 46% yield) 1H NMR (500 MHz, Chloroform-d) δ 7.86 – 7.78 (m, 4H), 7.72 – 7.68 (m, 2H), 7.35 (ddd, J = 11.1, 8.5, 7.6 Hz, 2H), 6.83 (ddd, J = 7.4, 6.0, 0.9 Hz, 2H), 4.24 – 4.12 (m, 2H), 3.99 (s, 3H), 3.87 – 3.73 (m, 2H), 2.07 – 1.91 (m, 4H). 13C NMR (126 MHz, Chloroform-d) δ 168.49, 155.20, 154.43, 133.90, 132.13, 126.68, 126.61, 125.15, 125.12, 123.22, 114.30, 114.13, 105.39, 104.49, 67.34, 55.53, 37.74, 26.74, 25.54.


MeO-Nap-O-Bu-NH3I (I): To a 100 mL round bottom flask fitted with a magnetic stir bar was added 50 mL of ethanol and 0.9 g (2.4 mmol) of H. To this was added 1.2 g of hydrazine monohydrate. The reaction was stirred at 70 °C for 4 hrs. The reaction was cooled to RT and ca. ½ of the ethanol was removed by rotary evaporation. To the resulting suspension, 50 mL of DCM was added and the mixture was filtered and the resulting solid washed with 50 mL of DCM twice. The filtrate was collected and solvent removed by rotary evaporation to give to a solid. This solid was suspended in 100 mL DCM and filtered. The solid was washed 2X with DCM and the filtrate collected. This process was repeated one more time. The resulting oil recovered after rotary evaporation and was precipitated with 100 mL water. The solid was filtered off and washed with a copious amount of water to remove residual hydrazine. This solid was then dissolved in 50 mL of dioxane and to this was added 0.6 g (2.7 mmol) 57 wt% hydroiodic acid containing no stabilizer. The solvent was removed from the resulting solution yielding a solid and this solid was first sonicated with diethyl ether and then transferred to a frit where it was washed with a copious

9

amount of diethyl ether. The resulting white solid was then dried under vacuum for several days (0.37 g, 42% yield). 1H NMR (500 MHz, DMSO-d6) δ 7.79 – 7.56 (m, 5H), 7.40 (dt, J = 8.4, 7.5 Hz, 2H), 6.99 (dd, J = 7.9, 1.0 Hz, 2H), 4.17 (t, J = 6.0 Hz, 2H), 3.95 (s, 3H), 2.92 (q, J = 6.7 Hz, 2H), 1.91 (ddd, J = 14.1, 7.8, 5.6 Hz, 2H), 1.85 – 1.73 (m, 2H). 13C NMR (126 MHz, DMSO-d6) δ 154.71, 153.84, 125.87, 125.84, 125.51, 125.42, 113.54, 105.80, 104.97, 66.34, 55.58, 25.74, 24.20.


MeO-Nap-O-Hex-Br (J): To a 250 mL round bottom flask fitted with a magnetic stir bar, 5-methoxynapthalene-1-ol (1.5 g, 8.6 mmol), and potassium carbonate (3.56 g, 25.8 mmol) were added. To this was added 75 mL of acetonitrile then 12.6 g of 1,6-dibromohexane (51.6 mmol), and the flask was heated in an oil bath at 65 °C overnight. The flask was then allowed to cool to room temperature and the solvent removed by rotary evaporation. Water was added to the resulting material and extracted with DCM three times. The combined organic extractions were extracted once with saturated NaCl and dried with anhydrous MgSO4 then concentrated by rotary evaporation. The resulting residue was chromatographed in 75:25 hexanes:dichloromethane. The product was collected, and the solvent removed by rotary evaporation to give a white solid (2.27 g, 78% yield) 1H NMR (500 MHz, Chloroform-d) δ 7.84 (ddt, J = 16.2, 8.5, 0.9 Hz, 2H), 7.37 (td, J = 8.7, 7.6 Hz, 2H), 6.84 (ddd, J = 8.6, 7.6, 0.9 Hz, 2H), 4.13 (t, J = 6.3 Hz, 2H), 4.00 (s, 3H), 3.44 (t, J = 6.8 Hz, 2H), 2.00 – 1.89 (m, 4H), 1.66 – 1.54 (m, 4H). 13C NMR (126 MHz, Chloroform-d) δ 155.26, 154.61, 126.75, 126.65, 125.21, 125.08, 114.27, 114.03, 105.35, 104.49, 67.91, 55.55, 33.85, 32.76, 29.17, 28.02, 25.57.

MeO-naphthalene-O-hexyl-pthalimide (K): To a 100 mL RBF fitted with a magnetic stir bar, J (1.8 g, 5.3 mmol), and potassium phthalimide (1.97 g, 10.6 mmol) were added. To this, 50 mL of DMF were added and the flask heated in an oil bath at 120 °C overnight. The reaction was allowed to cool and much of the DMF was removed by rotary evaporation. The resulting oil was precipitated in water and the precipitate recovered by filtration. The crude dry powder was chromatographed in 70:30 hexanes:ethyl acetate. The product was collected, and the solvent removed by rotary evaporation to give a white solid (2.04 g, 95% yield)

10

1H NMR (500 MHz, Chloroform-d) δ 7.88 – 7.77 (m, 4H), 7.73 – 7.67 (m, 2H), 7.35 (ddd, J = 9.4, 8.5, 7.6 Hz, 2H), 6.82 (ddd, J = 11.0, 7.7, 1.0 Hz, 2H), 4.11 (t, J = 6.3 Hz, 2H), 3.99 (s, 3H), 3.72 (t, J = 7.3 Hz, 2H), 2.00 – 1.86 (m, 2H), 1.81 – 1.69 (m, 2H), 1.68 – 1.57 (m, 2H), 1.52 – 1.41 (m, 2H). 13C NMR (126 MHz, Chloroform-d) δ 168.49, 155.21, 154.63, 133.85, 132.18, 126.74, 126.62, 125.20, 125.05, 123.18, 114.35, 113.94, 105.32, 104.47, 67.97, 55.53, 37.97, 29.22, 28.60, 26.71, 25.95.


MeO-Nap-O-Hex-NH3I (L): To a 100 mL round bottom flask fitted with a magnetic stir bar was added 50 mL of ethanol and 1 g (2.48 mmol) of K. To this was added 1.25 g of hydrazine monohydrate. The reaction was stirred at 70 °C for 4 hrs. The reaction was cooled to RT and ca. ½ of the ethanol was removed by rotary evaporation. To the resulting suspension, 50 mL of DCM was added, and the mixture was filtered and the resulting solid washed with 50 mL of DCM twice. The filtrate was collected, and solvent removed by rotary evaporation to give to a solid. This solid was suspended in 100 mL DCM and filtered. The solid was washed 2X with DCM and the filtrate collected. This process was repeated one more time. The resulting oil recovered after rotary evaporation and was precipitated with 100 mL water. The solid was filtered off and washed with a copious amount of water to remove residual hydrazine. This solid was then dissolved in 50 mL of dioxane and to this was added 0.68 g (3 mmol) 57 wt% hydroiodic acid containing no stabilizer. The solvent was removed from the resulting solution yielding a solid and this solid was first sonicated with diethyl ether and then transferred to a frit where it was washed with a copious amount of diethyl ether. The resulting white solid was then dried under vacuum for several days (0.38 g, 38% yield). 1H NMR (500 MHz, DMSO-d6) δ 7.75 – 7.67 (m, 2H), 7.61 (s, 3H), 7.44 – 7.33 (m, 2H), 7.01 – 6.93 (m, 2H), 4.14 (t, J = 6.3 Hz, 2H), 3.95 (s, 3H), 2.81 (ddd, J = 9.1, 7.3, 5.6 Hz, 2H), 1.94 – 1.75 (m, 2H), 1.64 – 1.48 (m, 4H), 1.48 – 1.36 (m, 2H). 13C NMR (126 MHz, DMSO-d6) δ 155.18, 154.47, 126.41, 126.32, 125.99, 125.91, 114.02, 113.89, 106.23, 105.43, 68.01, 56.06, 39.31, 28.95, 27.43, 25.98, 25.69.


11

Cl5Ph-O-Pr-BOC (M): To a 100 mL RBF was added 1.86 g (7 mmol) of pentachlorophenol, 2.89 g (21 mmol) of potassium carbonate and 50 mL of acetonitrile. To this was added 2.5 g (10.5 mmol) of 2-(Boc-amino)ethyl bromide. The resulting reaction mixture was heated overnight at 65 °C. The reaction was then allowed to cool and 50 mL of water was then added to the reaction mixture. The entire contents of the RBF were then poured into 500 mL of water. The resulting solid was recovered by filtration. Once this solid was dry it was chromatographed on silica gel with hexanes:ethyl acetate. The product was recovered by rotary evaporation (1.75 g, 59% yield). 1H NMR (500 MHz, Chloroform-d) δ 4.82 (s, 1H), 4.08 (t, J = 5.9 Hz, 2H), 3.43 (q, J = 6.5 Hz, 2H), 2.05 (p, J = 6.3 Hz, 2H), 1.45 (s, 9H). 13C NMR (126 MHz, Chloroform-d) δ 155.99, 151.57, 131.90, 129.44, 128.31, 79.34, 71.85, 37.84, 30.18, 28.44.


Cl5Ph-O-Pr-NH3I (N): To a 50 mL RBF with a magnetic stir bar was added 1 g (2.36 mmol) of M and 25 mL of dioxane. To this was added 0.78 g (3.5 mmol) of 57% hydroiodic acid containing no stabilizer. The reaction was stirred at 50 °C for 1 hr. The resulting solution was then evaporated to a solid. This solid was then suspended in diethyl ether and sonicated. The solid was then recovered by filtration and washed with a copious amount of diethyl ether. The resulting white solid was dried under vacuum for several days (0.9 g, 85% yield). 1H NMR (500 MHz, DMSO-d6) δ 7.90 – 7.48 (m, 3H), 4.14 (t, J = 6.1 Hz, 2H), 3.06 (q, J = 8.1, 7.2 Hz, 2H), 2.07 (ddt, J = 9.3, 7.7, 6.1 Hz, 2H). 13C NMR (126 MHz, DMSO-d6) δ 151.78, 131.50, 128.81, 128.28, 71.81, 36.77, 28.19.


12

Supplementary Table 1. Crystallographic details for n = 1 layered perovskites.

Compound # (R1 , R2) 3: butyl, H 4: hexyl, H 5: ethyl, OMe

ORTEP Platon Output via checkCIF 50% probability ellipsoid CCDC # 1934873 1934874 1934872

Precursor Salt

empirical formula C28H36O2N2PbI4 C32H44O2N2PbI4 C26H32O4N2PbI4

crystal system orthorhombic monoclinic orthorhombic space group Pca21 P21/c Pbca unit cell dimensions a, Å 8.53004(8) 25.9533(5) 8.8573(2) b, Å 8.99700(10) 24.9536(5) 8.7952(2) c, Å 46.0035(5) 9.1283(2) 42.8797(10) α, β, γ 90, 90, 90 90, 95.7540(10), 90 90, 90, 90 Refinement Parameters R1 (Fo > 4 sig(Fo)) 0.0562 0.0435 0.0703 R1 (all data) 0.0699 0.0519 0.0767 wR2 0.1617 0.1324 0.1662 Highest Peak (e/A3) 1.58 1.85 1.66

Deepest Hole (e/A3) -2.06 -1.70 -1.71

13

Compound # (R1 , R2) 6: butyl, OMe 7: hexyl, OMe 8: Cl5Ph-O-propyl

ORTEP PLATON Output via checkCIF 50% probability ellipsoid CCDC # 1934871 1934875 1934876

Precursor Salt

empirical formula C30H40O4N2PbI4 C34H48O4N2PbI4 Cl10C18H18O2N2PbI4

crystal system orthorhombic triclinic monoclinic space group Pbcn P1bar P21/n unit cell dimensions a, Å 49.284(8) 8.7605(2) 8.8252(3) b, Å 6.0801(10) 8.8195(2) 9.0770(3) c, Å 12.290(2) 27.8372(11) 43.1521(14) α, β, γ 90, 90, 90 87.08, 87.97, 89.75 90, 91.429(2), 90 Refinement Parameters R1 (Fo > 4 sig(Fo)) 0.0587 0.0505 0.0874 R1 (all data) 0.0998 0.0994 0.1087 wR2 0.1565 0.1473 0.2547 Highest Peak (e/A3) 0.89 0.98 1.98 Deepest Hole (e/A3) -1.17 -0.97 -1.47

14

B: FILM PREPARATION

Film Preparation: Characterization of thin films by GIWAXS and PXRD

Grazing-incidence wide-angle X-ray scattering (GIWAXS) was performed at Argonne National

Labs (ANL) Advanced Photon Source (APS) Sector 8-ID-E at beam energy 10.92 keV and

incident angle 0.14o. Data analysis was performed using GIXSGUI provided by Sector 8.3 Due to

the highly textured nature of n = 1 layered perovskites, traditional θ - 2θ powder X-ray diffraction

(PXRD) can only provide information about the layered axis and how it is modulated by the

incorporation of TCBQ. Two dimensional GIWAXS captures both the layered reflections

observed by PXRD as well as off-axis reflections corresponding to the in-plane inorganic lattice.

In samples containing no TCBQ, we can use GIWAXS to verify that the unit cell measured from

single-crystalline samples matches that of the thin-film samples (Supplementary Figure 1). This

allows structural comparisons to be made between the structure understood by single-crystal

measurements and the behavior of these samples in thin-film. GIWAXS for compounds 1, 2, 5, 6,

and 7 with and without TCBQ are provided in Supplementary Figures 3, 4, 5, 6, and 7 respectively.

In samples with large changes in the layered axis upon TCBQ incorporation (Compound 5,

Supplementary Figure 5, is a representative example), there is a progressive shift in the layered

reflections to lower q upon increasing TCBQ incorporation (Supplementary Figure 5e). These are

the observations that can be made by PXRD. Through analysis of the off-axis reflections, we can

see that these reflections are similarly translated to lower q in the Z direction (vertical direction)

but are not translated in q in the Y direction (horizontal direction). This indicates that the lattice is

expanding in the layered axis but not in the in-plane axis. These observations are commensurate

with TCBQ introduction into the organic layer resulting in layer expansion with minimal to no

distortion in the inorganic lattice. This type of phenomenon is also observed in Compound 1

(Supplementary Figure 3) and Compound 6 (Supplementary Figure 6). In the remainder of the

samples, the relatively small changes in layered spacing effectively reveal no change in the off-

axis reflections. Extensive analysis is further limited by the large beam cross-section inherent in

grazing incidence measurements and thus we can say that in all of the compounds that incorporate

TCBQ, the distortion of the in-plane inorganic lattice is less than what can be measured by

GIWAXS. Thus the changes in optoelectronic properties are the result of doping TCBQ into the

organic layers. Note that there tends to be a textural change in these samples upon TCBQ

15

incorporation. By GIWAXS, we observe in most cases that samples become less textured upon TCBQ

incorporation or have no change in texture. In compound 2 we observe more texture upon TCBQ

incorporation. This is likely due to suppression of crystallization between crystalline grains in the later parts

of the film formation mechanism which minimizes the contribution of these more disordered grains to the

final GIWAXS pattern (Supplementary Figure 8). Of note, the films with TCBQ also tend to be

smoother in Compound 2.

Supplementary Figure 1 GIWAXS compounds 1-7 (a-f). Overlaid spots are predicted from the unit-cell determined through single crystal X-ray crystallography. There is good agreement between predicted and observed reflections indicating the structures determined in single crystal samples are representative of those in thin film. In compounds 2 and 4, the samples are highly twinned and lattice appears as orthorhombic transformed lattice with double the layered cell axis.

16

Supplementary Figure 2. Full width half-max (FWHM) of the 200 reflection of compound 2 calculated through a Gaussian fit of the raw data. Instrumental broadening is approximately 0.01o2θ.

17

Supplementary Figure 3. GIWAXS of Compound 1. (a) Without TCBQ in formulation (x = 0 eq). Film is textured. Region 1 shows off-axis reflections recolored for overlay. Line cuts are taken of region 2 to show layered axis which is observed in PXRD experiments. (b) GIWAXS Compound 1, x = 0.5 eq. Region 1 shows off-axis reflections colored for overlay. (d) Overlay of region 1 for two samples showing a vertical displacement of off-axis peaks indicative of layered expansion but no horizontal displacement, indicating minimal distortion of the in-plane inorganic lattice. (e) Line cut along region 2 showing layered lattice expansion with increasing TCBQ and overlay of layered reflections showing the same.

18

Supplementary Figure 4. GIWAXS of Compound 2 (a) Without TCBQ in formulation (x = 0 eq). Film is textured. Region 1 shows off-axis reflections recolored for overlay. Line cuts are taken of region 2 to show layered axis which is observed in PXRD experiments. (b) GIWAXS Compound 2, x = 0.5 eq. Region 1 shows off-axis reflections colored for overlay. (c) GIWAXS Compound 2, x = 1 eq. Region 1 shows off-axis reflections colored for overlay. (d) Overlay of region 1 for three samples. No change is observed other than the texture of each sample in these off-axis reflections. This indicates minimal distortion of the in-plane inorganic lattice. (e) Line cut along 2 showing layered lattice expansion with increasing TCBQ and overlay of layered reflections showing the same.

19

Supplementary Figure 5. GIWAXS of Compound 5 (a) Without TCBQ in formulation (x = 0 eq). Film is textured. Region 1 shows off-axis reflections recolored for overlay. Line cuts are taken of region 2 to show layered axis which is observed in PXRD experiments. (b) GIWAXS Compound 5 x = 0.5 eq. Region 1 shows off-axis reflections colored for overlay. (c) GIWAXS Compound 5 x = 1.0 eq. Region 1 shows off-axis reflections colored for overlay. (d) Overlay of region 1 for three samples showing a vertical displacement of off-axis peaks indicative of layered expansion but no horizontal displacement indicating minimal distortion of the in-plane inorganic lattice. (e) Line cut along 2 showing layered lattice expansion with increasing TCBQ and overlay of layered reflections showing the same.

20

Supplementary Figure 6. GIWAXS of Compound 6 (a) Without TCBQ in formulation (x = 0 eq). Film is textured. Region 1 shows off-axis reflections recolored for overlay. Line cuts are taken of region 2 to show layered axis which is observed in PXRD experiments. (c) GIWAXS Compound 6 x = 1 eq. Region 1 shows off-axis reflections colored for overlay. (d) Overlay of region 1 for two samples showing a vertical displacement of off-axis peaks indicative of layered expansion but no horizontal displacement indicating minimal distortion of the in-plane inorganic lattice. (e) Line cut along 2 showing layered lattice expansion with increasing TCBQ and overlay of layered reflections showing the same.

21

Supplementary Figure 7. GIWAXS of Compound 7 (a) Without TCBQ in formulation (x = 0 eq). Film is textured. Region 1 shows off-axis reflections recolored for overlay. Line cuts are taken of region 2 to show layered axis which is observed in PXRD experiments. (b) GIWAXS Compound 7 x = 0.5 eq. Region 1 shows off-axis reflections colored for overlay. (c) GIWAXS Compound 7 x = 1 eq. Region 1 shows off-axis reflections colored for overlay. (d) Overlay of region 1 for three samples. No change is observed other than the texture of each sample in these off-axis reflections. This indicates minimal distortion of the in-plane inorganic lattice. (e) Line cut along 2 showing layered lattice expansion with increasing TCBQ and overlay of layered reflections showing the same.

22

Supplementary Figure 8. (a) Compound 2 texture upon TCBQ incorporation. Without TCBQ, there are strong central peaks with tails that spread in arcs about the center of the reflected beam. This indicates generally strong alignment, with some smaller domains that exhibit more misalignment. As TCBQ content increases, these tails decrease and only the central peaks remain, leading to a more textured film. (b) Schematic of proposed film structure where the lack of TCBQ results in small disordered grains that grow between the larger well oriented crystalline domains. (c) TCBQ suppresses crystallization at grain boundaries and thus increases the texture of the resultant films.

23

Solution characterization

Supplementary Figure 9. (a) UV-Vis absorption of the spin coating solution (1 cm path length) for perovskite 1 with TCBQ (x = 1 eq.) formulated at 1 wt% in DMF/DMSO (blue), compared to a 1 wt% TCBQ solution in DMF/DMSO (orange). (b-e) UV-Vis absorption spectra for thin film sample controls: (b) Nap-O-Pr-NH3Br salt formulated with TCBQ, showing a strong CT band between 1.6-2.2 eV despite absence of I– . (c) Aprotic dimethoxynaphthalene and TCBQ, showing a strong CT band in the same energy range as (b), and indicating that the CT band does not originate from the presence of a charged salt. (d) Iodide salt of tetrabutylammonium formulated with TCBQ, showing no CT band and indicating that the formation of I2 is not responsible for the observed CT bands. (e) Thin film absorption of TCBQ alone (red) and Nap-O-Pr-NH3Br film (grey), for comparison. Due to the different solubility of these organic molecular systems, films (b-e) were formulated in acetone and dropcast on quartz. This solvent produced higher quality films compared to DMF/DMSO, and prevented the need for annealing to drive off the solvent.

24

Supplementary Figure 10. Four formulations of solids at 20 wt% in 50:50 DMF:DMSO to demonstrate the need for intermediate donor-acceptor complexation in tandem with perovskite assembly. At bottom, the formulation of compound 2 without a small molecule acceptor is yellow, due to dissolved PbI2, but shows no absorbance from charge transfer interactions. The three samples above, on the other hand, contain small molecule acceptors and appear dark. The formulation for TCBQ (tetrachloro-1,2-benzoquinone) is dark but transparent. In contrast, the formulations with either tetrachloro-1,4-benzoquinone or tetrafluoro-1,4-benzoquinone result in insoluble aggregates, which prevents the use of these formulations for film fabrication.

25

Supplementary Figure 11. NMR experiments reveal that TCBQ may be partially degraded to tetrachlorocatechol on the order of several hours or days. This results from a two-proton, two-electron

process in which the anhydrous anaerobic conditions of the glove box preparation environment may result in the reduction of the ammonium iodide (2NH4I → I2 + 2NH2). (a) 1H NMR of the spin coating solution formulated in DMSO-d6 at 10 wt% measured at 6 hrs, 30 hrs, and 10 days (blue labels). A broad peak at 10.5 ppm appears with time, consistent with tetrachlorocatechol in DMSO and 1 eq. tetrachlorocatechol added to the perovskite precursor mixture (yellow labels). (b) 13C NMR of the same solutions at 6 hr, 30 hr, and 10 days. Samples were also prepared with 20% non-deuterated DMF and the same trends were observed. We note that TCBQ itself is not directly observable in DMSO due to aggregation at both low and high concentrations. However, the decomposition product from the 2H+/2e- redox reaction is observable. This appears after significant time, over several hours to several days. Because spin-coating solutions are used within 30 min of preparation in this work, precursor solution degradation is largely absent.

26

SEM-EDS analysis to determine Cl:I ratio in crystalline grains

Supplementary Figure 12. PXRD of compound 2 before and after treatment with DCM. Samples were dried in vacuum for 24 hrs before measurement. No change in layered spacing was observed in the perovskite films without TCBQ. Layered lattice expansion was observed in TCBQ films indicating that more TCBQ is recruited from the grain boundaries to the organic layers upon DCM treatment.

Supplementary Figure 13. (a) Schematic showing the film washing step. TCBQ is dissolved out of the grain boundaries and results in delamination of the film. These fragments were then redeposited on glass for analysis. (b) Film fragments under bright field and cross-polarized magnification. Faint illumination in cross-polarizations shows crystallinity in these film fragments.

27

Supplementary Figure 14. Elemental analysis of compound 2, x = 0 eq TCBQ. (a) SEM-EDS. No chlorine is observed in EDS. (b,c) Elemental maps of scraped thin films. Pb and I are co-localized and the Cl background is evenly distributed.

Supplementary Figure 15. Elemental analysis of compound 2, x = 0.5 eq TCBQ. (a) SEM-EDS. Chlorine is observed in EDS. I:Pb ratios were less reliable, whereas Cl:I ratios produced more reliable results for quantification. (b,c) Elemental maps of film fragments. Pb, I, and Cl are co-localized.

28

Supplementary Figure 16. Elemental analysis of compound 2, x = 1.0 eq TCBQ. (a) SEM-EDS. Chlorine is observed in EDS. (b,c) Elemental maps of film fragments. Pb, I, and Cl are co-localized.

Supplementary Table 2. Summary of EDS analysis for Cl-I ratio of compounds 2, 6, and 7.

Compound TCBQ in

formulation (x)

Cl:I Determined by

EDS (c) Interpreted Dopant Formula

2 - Nap-O-Pr 0 0.00 C26H32O2N2PbI4 2 - Nap-O-Pr 0.5 0.15 ± 0.03 C26H32O2N2PbI4·(C6O2Cl4)0.15 2 - Nap-O-Pr 1 0.34 ± 0.04 C26H32O2N2PbI4·(C6O2Cl4)0.34

6 - MeO-Nap-O-Bu 1 0.22 ± 0.03 C30H40O4N2PbI4·(C6O2Cl4)0.22 7 - MeO-Nap-O-Hex 1 0.37 ± 0.06 C34H48O4N2PbI4·(C6O2Cl4)0.37

Note on Supplementary Table 2:

We note that these measurements likely overestimate the amount of TCBQ incorporated within the crystalline domains of 2 because they inherently include TCBQ molecules that are trapped at boundaries inaccessible to DCM, as well as TCBQ that is incorporated without donor-acceptor interactions. Therefore, viewed from the electronic perspective, the influence of TCBQ as a molecular dopant is likely more powerful per mole of dopant than we report.

29

Annealing effects on Compound 2 with 1 eq TCBQ (x = 1)

Supplementary Figure 17. Variable temperature annealing of a film of Compound 2 with 1 eq TCBQ. (a) PXRD showing that as annealing temperature is increased, the extent of lattice expansion decreases, indicating that less TCBQ is incorporated in the organic layers. (b) Corresponding UV-Vis absorption spectra, showing shifting and broadening of the 1s exciton peak to lower energy as annealing temperature is increased, indicating less TCBQ incorporation. (c) Plot of the change in d-spacing relative to 2 without any dopant vs. annealing temperature. (d) Plot of the change in the 1s exciton energy vs. annealing temperature. The difference in the slope of (c) and (d) is likely accounted for by the substantial broadening of the 1s peak and its shift to lower energy. Based on these annealing studies, a temperature of 100 °C was chosen for the annealing step in film preparation elsewhere, to reduce film heterogeneity and result in a sharper 1s exciton peak.

30

C: OPTICAL AND STRUCTURAL CHARACTERIZATION

Note on unidentified PXRD peaks

We note the appearance of diffraction peaks at 5.5 and 11 degrees 2θ in the PXRD of compound 2, as well

as most other perovskite films studied in this work, which are likely impurity peaks unrelated to the optically

active perovskite and do not represent a new layered perovskite phase. We believe these peaks belong to

an as yet unidentified crystalline phase associated with disruption of the perovskite assembly, thus making

many of these samples biphasic. The reflections for this second crystalline phase do not correspond to the

diffraction of any individual precursor component on their own or any binary combinations thereof. Since

the peak positions of this second crystalline phase do not change across the family of compounds tested,

this phase cannot be related to the varying organic ammonium iodide salts (which have unit cells that

diffract at unique 2θ values). Most importantly, in contrast to the overall progressive shift of the perovskite

lattice diffraction in all compounds studied as TCBQ is incorporated, the peaks of this second crystalline

phase do not shift at all with increasing TCBQ content. To further investigate this phase, we prepared a

film from a solution of compound 2 with 1 eq. tetrachlorocatechol instead of TCBQ (Supplementary Figure

23) as a control experiment. Tetrachlorocatechol is not incorporated into the perovskite lattice (no shift in

crystal diffraction), yet is capable of disrupting the perovskite assembly. Indeed, we find that in the PXRD

of this control film, the diffraction peaks corresponding to the unknown phase are less intense but appear

at the same position. We therefore conclude that these peaks correspond to a crystalline phase that excludes

the parent ammonium iodide cation molecule, TCBQ, and the optically active perovskite phase. The

enhancement of this second crystalline phase is a consequence of the introduction of TCBQ insofar as it

becomes less favorable for the perovskite to form, but this phase is distinct from the progressive shifts in

lamellar ordering and in optical absorption associated with uptake of TCBQ into the perovskite lattice.

31

C2. Optical and structural characterization – PXRD and UV-Vis of Compounds 1, 3-7

Supplementary Figure 18. Compound 1 (naphthalene-O-ethyl-NH3

+)2PbI4 + x∙TCBQ formulation studies. (a) PXRD showing that with increasing TCBQ, there is a progressive expansion in layer spacing, although crystallinity appears dramatically reduced at higher TCBQ amounts. (b) UV-Vis absorption spectra for x = 0, 0.2, 0.4, and 0.6 eq TCBQ, which show no change in the exciton peak, and x = 0.8 and 1 eq, which show diminished excitonic absorption caused by low crystallinity. (c) Plot of change in d-spacing vs. equivalents of TCBQ (x) in the film precursor solution.

Supplementary Figure 19. Compound 5 (MeO-naphthalene-O-ethyl-NH3

+)2PbI4 + x∙TCBQ formulation studies. (a) PXRD showing with increasing TCBQ, there is a progressive expansion in layer spacing. (b) UV-Vis absorption spectra showing a progressive shift to higher energy of the 1s exciton feature with increasing TCBQ (x). (c) Plot of change in d-spacing vs. amount of TCBQ (x). (d) Plot of change in the energy of the 1s exciton feature vs. amount of TCBQ (x) in film precursor solution.

32

Supplementary Figure 20. Compound 6 (MeO-naphthalene-O-butyl-NH3

+)2PbI4 + x∙TCBQ formulation studies. (a) PXRD showing with increasing TCBQ, there is a progressive expansion in layer spacing. (b) UV-Vis absorption spectra show a progressive shift to higher energy of the 1s exciton feature. Note the complex structure of the x = 0 spectra. The crystal structure shows disorder with Pb-I-Pb bond angles of 146o and 150o. The two peaks may be resulting from local separation within the crystal structure, the higher energy peak is more appropriate for a bond angle of 146o and the lower energy peak more appropriate for a bond angle of 150o. The general trend with increasing dopant is clear, but specific interpretation is challenging. (c) Plot of change in d-spacing vs. formulation amount of TCBQ (x). (d) Plot of change in the energy of the 1s exciton feature vs. formulation amount of TCBQ (x).

Supplementary Figure 21. Compound 7 (MeO-naphthalene-O-hexyl-NH3

+)2PbI4 + x∙TCBQ formulation studies. (a) PXRD showing that with increasing TCBQ there is a progressive expansion in layer spacing. (b) UV-Vis absorption shows a progressive shift to higher energy of the 1s exciton feature. (c) Plot of change in d-spacing vs. amount of TCBQ (x). (d) Plot of change in the energy of the 1s exciton feature vs. formulation amount of TCBQ (x).

33

Optical and structural characterization control experiments

Supplementary Figure S22. Formulation studies of aliphatic layered perovskites with or without the addition of small molecule acceptor TCBQ. (a) PXRD and (b) UV-Vis absorption spectra of butylammonium lead iodide with and without TCBQ; no change in diffraction or optical absorption is observed, indicating TCBQ is not incorporated into the perovskite lattice of this compound. (c) PXRD and (d) UV-Vis absorption spectra of hexylammonium perovskite with and without TCBQ; no incorporation is observed by PXRD (e) PXRD of a film of compound 8 compared to the predicted PXRD from single crystal structure factors. Only layered reflections appear in PXRD due to texture of film. This shows that the thin film structure is the same as observed by single crystal XRD (f) Corresponding room temperature optical absorption of compound 8.

34

Addition of molecular iodine and tetrachlorocatechol control

Supplementary Figure 23. PXRD and UV-vis absorption spectra for thin film control samples. (a) The precursor iodide salt of compound 2 was formulated with 0.5, 1.0, and 1.5 eq of molecular iodine (I2) relative to PbI2. No change in X-ray scattering or optical absorption was observed, indicating that the presence of molecular iodine is not be responsible for the layer expansion or the changes in optical absorbance observed in this work. (b) 1 eq of tetrachlorocatechol relative to PbI2 was added to the spin coating solution of compound 2 (green), and no changes in peak positions of either the X-ray or UV-vis was observed. In grey, an equilibrium between I2 and I3

- was induced by the addition of 1 eq of I2 and 1 eq of tetrabutylammonium iodide to form the triiodide species, and no change to the excitonic optical absorption or the position of the perovskite PXRD peaks was observed. The film quality of the

35

tetrabutylammonium iodide sample was poor, resulting in low scattering signal in X-ray diffraction and high diffuse optical scattering.

Summary of change in E1s vs. change in d-spacing

Supplementary Figure 24. Compiled ΔE1s vs. Δd for compounds 1, 2, 5, 6, and 7, showing the relationship between layer expansion along stacking axis and the change in optical properties.

36

D: STRUCTURAL DISCUSSION OF INCORPORATION REGIMES Structural dependence of dopant incorporation. Upon doping of compound 2 with TCBQ, the layered

lattice expands and there is a shift in the 1s exciton peak, which we attribute to donor acceptor interactions

in the organic layers (Regime 1). To explore the role of cation structure on TCBQ incorporation we

expanded these studies to compound 1, and 3-7. Optical and X-ray diffraction data for compounds 1 and 3-

7 are summarized in Supplementary Figures 18-21. Surprisingly, TCBQ incorporation was not consistent

across all seven compounds, even though the naphthalene donors should have equal molecular affinity for

binding to TCBQ. Compounds 5-7 incorporated TCBQ and had evident changes in their optical absorption

consistent with the behavior of compound 2 (Regime 1). Compound 1 showed layered lattice expansion

with no corresponding change in optical absorption (Regime 2). Compounds 3 and 4 did not show any

increase in the layer spacing, and their optical absorption remained the same (Regime 3). The stark

differences in incorporation behavior despite nearly identical donor Nap units indicates the importance of

the structural conformation of the naphthalene within the crystal structure.

To isolate the differences between Regimes 1 and 2, we have relied on washing studies similar to

those performed to identify the incorporation of TCBQ in compound 2. Surprisingly, the incorporation of

TCBQ within the organic layers can be manipulated after the annealing step by washing with

dichloromethane (DCM), which removes excess TCBQ at the grain boundaries within the films but does

not dissolve the perovskite structure. PXRD confirms that the crystallinity of the samples with and without

TCBQ in the formulation is maintained and that there is no change in undoped samples (x = 0) before and

after DCM treatment (Supplementary Figure 12). By analyzing the PXRD data for compounds 1-7, we have

identified three distinct behaviors of TCBQ incorporation through comparing the layered spacing of these

materials before and after DCM washing experiments.

Upon washing thin films with DCM, compounds in Regime 1 showed an increase in layered

spacing, indicating that some of the TCBQ originally present at the grain boundaries is recruited and

incorporated into the organic galleries (Supplementary Figure 25). Furthermore, addition of TCBQ to films

in Regime I had strong effects on the optical absorption. Compounds 2, 6, and 7 fall into this regime.

In Regime 2, the layered spacing of TCBQ-doped films was greater than undoped films prior to

DCM washing, yet these films showed a contraction in layered spacing back to the undoped layered spacing

after the washing step (Supplementary Figure 26). This indicates that the TCBQ within the organic layers

is much more weakly bound and therefore readily removed by DCM. Weak donor-acceptor or hydrophobic

binding may indicate why no change in optical properties are observed in these materials. Compound 1

falls into this regime.

37

When comparing the crystal structures of Compound 1 to that of 2, 6, and 7, we can see that the

naphthalene units of cations on each side of the van der Waals gap have different characteristic packing

which may indicate the structural origins responsible for the stronger donor-acceptor interactions necessary

to cause changes in binding energy observed in compounds 2, 6, and 7. In compounds 2, 6, and 7 the

naphthalene units on each side of the van der Waals gap adopt intralayer edge-face interactions where the

faces of the individual naphthalene units remain relatively exposed and capable of binding the TCBQ

dopant through donor acceptor interactions (Supplementary Figure 27). Compound 1, however, has

naphthalene units that adopt intralayer face-face interactions. This makes the faces of the naphthalene units

comparatively less available for strong interaction with TCBQ and this structure allows TCBQ to be readily

removed by DCM washing, as it is only incorporated through weak interactions.

Finally, compounds 3 and 4 do not appear capable of incorporating TCBQ directly into the organic

sublattice; we deem this Regime 3. Neither the PXRD nor the optical absorption are influenced by the

presence of TCBQ in the spin-coating formulation for these structures. Given that compound 2 (containing

the same donor unit), and compounds 6 and 7 (containing the same respective linker lengths) both

incorporate TCBQ and show corresponding changes in the optical absorption, we find that there is a specific

structural conformation enabled in 3 and 4 that inhibit TCBQ incorporation. In the crystal structure of

compound 4, we can see possible origins of this phenomenon. Whereas most n = 1 layered perovskites with

monofunctional cations have space between the organic bilayers that constitutes a van der Waals gap,

compound 4 shows strong π-π interactions between the naphthalenes on opposing sides of this gap. This

occurs because the naphthalenes from one side of the organic lattice interdigitate with naphthalenes from

the opposing side. This effectively eliminates the bilayer van der Waals gap (Supplementary Figure 28),

and this dense packing due to strong intra-naphthalene π-π interactions likely makes it unfavorable to

incorporate TCBQ. Similarly, in compound 3, we see strong π-π interactions across the van der Waals gap

where the entire edge of one naphthalene unit lies along the entire face of its neighboring naphthalene

(Supplementary Figure 28). To formalize these observations, we have defined a plane of atoms given by

the naphthalene carbon furthest from the inorganic lattice in each crystal structure and measured the plane-

to-plane distance across the van der Waals gap (Supplementary Figure 28). Both compounds 3 and 4 have

the smallest plane-to-plane distance which we attribute to the high degree of interaction between

naphthalene units across the van der Waals gap. We propose that this strong binding creates an additional

energetic penalty to TCBQ binding in cases where the donor-acceptor interactions are not strong enough to

overcome these naphthalene π-π interactions. In contrast, we find that the naphthalene donors with R2 =

MeO all incorporate TCBQ, which may be attributed to the bulkiness of this group decreasing strong π-π

interactions between naphthalene units.

38

A schematic illustration of the three incorporation regimes is shown in the main text (Figure 7d).

In this system, absolute understanding of the structural effects on incorporation is limited by the

incorporation regime doping type. Pursuit of single crystalline systems containing strong donor-acceptor

pairs such as these is a logical next step and should provide insight in this regard. What has been identified

here is that donors with the same electronic structure can result in different incorporation of TCBQ. This

reveals the role that cation structure plays in tuning these interactions.

Supplementary Figure 25. Regime 1: (a) DCM washing experiments of compound 2 showing layer expansion that results from the additional uptake of TCBQ into the organic layers upon DCM washing. (b) DCM washing experiments of compound 6 showing the same effect. (c) Schematic of proposed mechanism where additional TCBQ is incorporated in the organic layer from the grain boundaries upon washing with DCM. This incorporation is thought to be driven by relatively strong donor-acceptor interactions that reduce exciton binding energy.

39

Supplementary Figure 26. Regime 2: (a) DCM washing experiments for Compound 1. Addition of TCBQ results in lattice expansion observed in thin-film. Upon washing of the film with DCM, the lattice contracts to near the original layered spacing of (naphthalene-O-ethyl-NH3

+)2PbI4. There is also a reduction of crystallinity shown by the broadening of the diffraction peaks. (b) Proposed mechanism where TCBQ is believed to be incorporated weakly between the organic layers through relatively weak donor-acceptor interactions and hydrophobic interactions. Upon DCM washing, these weakly-held TCBQ molecules can be solvated and freed from the organic layer, resulting in lattice contraction. The weak nature of the donor-acceptor interactions may explain why no change in optical properties are observed upon TCBQ incorporation.

40

Supplementary Figure 27. Structural origins of the incorporation differences between regimes 1 and 2. (a) Compound 1 Nap-O-Ethyl units (red) of one layer show intralayer face-to-face interactions. This occupies the faces of the naphthalene units and likely inhibits the face-to-face interaction of naphthalene units with TCBQ. Instead, TCBQ collects within the van der Waals gap between layers and a reduction in exciton binding energy via donor-acceptor interaction is not observed. (b) Compound 2 Nap-O-Propyl units form a herringbone arrangement with intralayer edge-to-face interactions. This leaves one of the benzene faces of the arene accessible for TCBQ interactions, likely yielding stronger donor-acceptor complexation. (c) Compound 6 and (d) Compound 7 also exhibit a herringbone arrangement and have similar incorporation availability, explaining their comparable change in E1s.

41

Supplementary Figure 28. (a) Measurement of van der Waals gap in the six naphthalene containing perovskite crystal structures in this work. Measurements were made from the most peripheral carbon of the naphthalene on one-side of the van der Waals gap to the most peripheral carbon on the other side of the gap which is represented by the orange atoms in c and d. (b) Strong edge-face π stacking exhibited by compound 3 across the van der Waals gap. (c) In the case of compound 4, no gap is observed. Cations from one side interdigitate with cations from the other, resulting in a negative gap measurement. Both compounds 3 and 4 do not incorporate TCBQ. (d) Comparison with compound 5, which incorporates TCBQ and has a larger gap.

42

E: PHOTOLUMINESCENCE SPECTROSCOPY Lifetime measurements were collected using a spectrally-resolved, time-correlated single photon counting

(TCSPC) set-up. An avalanche photodiode (Microphotonic Devices) measured the PL decay of the

spectrally dispersed light through a slit at the wavelength of the FE band for each film of 2 with 0, 0.5, and

1.0 eq TCBQ, as well as the BE band with 1.0 eq TCBQ.

A single exponential decay convolved with a Gaussian response function (50-60 ps) was used to

fit the short component, found to be 250 ps for 2 + 0 eq TCBQ, 200 ps for 2 + 0.5 eq TCBQ, and 320 ps

for 2 + 1.0 eq TCBQ, with errors defined by the instrument response. The long component at the FE band

for the doped and undoped films could not be fit to a sum of exponentials, although the decay of the BE

signal in 2 + 1.0 eq TCBQ has appreciable signal and shows an even more significant long component. The

BE decay is appropriately fit to a biexponential decay with τ1 = 490 ± 0.05 ps (83%) and τ2 = 3.4 ± 0.8 ns

(17%). The long component at the FE band for the doped and undoped films could not be fit to a sum of

exponentials, although the decay of the BE signal in 2 + 1.0 eq TCBQ has appreciable signal and shows an

even more significant long component.

These lifetime measurements show that the major decay component of the FE band is similar across

the films of 2 both with and without TCBQ, as expected for a series in which both the organic and inorganic

lattices remain structurally similar. The relative amplitude differences for the longtime component as

dopant increases, and between the FE and BE bands, further suggests the existence of an equilibrium

between trap states and the free exciton recombination, but could also point towards a population of triplet

states due to the strong spin-orbit coupling in lead iodide perovskites.4-5

43

Supplementary Figure 29. Left panel: Photoluminescence spectra at selected temperatures for 2 with (a) 0 eq TCBQ, (b) 0.5 eq TCBQ, and (c) 1 eq TCBQ. Right panels: (d) FE peak center energies plotted as a function of temperature. (e) One-term Arrhenius equation, with Eb fixed to 400 meV from Elliott model fit, to the integrated PL intensity of 2 with 0 eq TCBQ. (f) Normalized PL decays of FE band intensity for 0, 0.5, and 1 eq TCBQ and for BE band intensity with 1 eq TCBQ.

44

Supplementary Figure 30. Optical micrographs at 40x magnification of thin films of 2 with 0 eq TCBQ (left), 0.5 eq TCBQ (middle), and 1 eq TCBQ (right column), with area of more homogeneity (b) and a cluster (a) which show that areas with greater defect-like character have comparatively greater intensity in the low energy emission (BE) band vs the free exciton (FE) band.

45

Supplementary Figure 31. Photoluminescence spectra (left) in the vicinity of the FE band at 5 K in single crystals of 2 at five different locations on the sample, highlighted by colored target symbols in optical micrographs (right). Fits to two Lorentzian lineshapes are overlaid (dotted lines) and demonstrate that the energy spacing varies over several meV from region to region within the crystal, but two peaks are always needed to capture the FE fine structure.

46

Supplementary Figure 32. Photoluminescence excitation (PLE) spectra of compound 2 films below 20 K (left), with 0.0 eq TCBQ in red, 0.5 eq in purple, and 1 eq in blue. On the right, insets show magnified views of the PLE spectra, with arrows identifying specific spectral features and their approximate energy. The low PL quantum yield of the 0.5 eq and 1 eq TCBQ films combined with 1s exciton resonances at energies much closer to Eg results in a sharp increase in the background signal for the PLE of the two doped samples. Excitation spectra were acquired on samples in an optical cryostat, by detecting the emission at the 1s exciton energy (2.58, 2.62, and 2.66 eV for 0 eq, 0.5 eq, and 1 eq TCBQ, respectively), with 1.5 s integration time per point (1 nm increments). The entrance and exit slits were set at 2 nm and 10 nm.

47

F: FIT OF ABSORPTION SPECTRA

Construction of modified 2D Elliott model

Our modified formula models each excitonic transition with some distribution function g(ℏω) broadened

by a finite linewidth Γn and centered at Ens, that is scaled by some amplitude An. In 2 + 0 eq TCBQ, the fine

structure of the excitonic transition is resolvable, and necessitates fitting with two peaks spaced by 20-30

meV. The fine structure used in our fit is further justified by the split band in single crystal PL measurements

of 2 (Supplementary Figure 31). Upon the introduction of 0.5 and 1 eq TCBQ, the absorption features

become increasingly broadened, which obscures this fine structure and enhances the asymmetry of the

exciton peaks, consistent with its attribution to local disorder.6-7 Thus in the doped films, the 1s transition

is modeled solely with an empirical asymmetric piecewise Lorentzian-Gaussian profile.

To fit the finitely broadened onset of the band edge continuum, we employ a logistic function centered

at Eg and broadened by a factor k related to Γg. There is some discrepancy in the literature as to the origin

of the absorption onset above 2.7 eV and the energy of the band gap, Eg. In Tauc plot analyses that have

been commonly applied for similar perovskite systems, a tangent line along this onset is extrapolated to α2

= 0 to measure Eg.7-9 However, Blancon et al used photoluminescence excitation (PLE) spectroscopy

together with magnetoabsorption and theoretical modeling to show that the absorption onset above 2.7 eV

in n = 1 lead iodide 2DLPs is in fact largely due to 2s exciton absorption (in linear combination with higher

excitons and the band edge) such that the difference in energy between the 1s and 2s excitons represents a

lower limit to Eb.10 Based on agreement between experimental results and their theoretical model, they

determined that Eg = 3.016 eV for the n = 1 butylammonium lead iodide perovskite. This agrees with other

recent DFT calculations that yield Eg = 2.9–3.1 eV for similar n = 1 lead iodide perovskites,11 and aligns

with results from other 2D materials12 where excitons with principal quantum numbers n ≥ 2 have

significant oscillator strength due to dielectric mismatch.13-14

This interpretation is also most consistent with our analysis, in which in the case of 0.5 eq TCBQ

(Figure 5, middle panel) there is a valley between the excitonic transition ~2.6 eV and the band-like

absorption; with 1 eq TCBQ, the higher-energy excitons are close enough to the band edge ~3 eV that a

distinct peak emerges, particularly at low temperatures.

In a classical inorganic quantum well, the progression of higher excitonic states can be described by

the 2D hydrogenic model in which Eb(m) = E0/(m – ½)2, with principle quantum number m and effective

Rydberg energy E0. 2D excitonic absorption spectra (α = αexciton + αcontinuum) were fit to a linear combination

of the following functions of peak center xc, amplitude A, and linewidth Γ or broadening factor k.

48

• Lorentzian: ℓ(xc) = !∙#ℓ"

(%&%#)"(#ℓ" (1)

• Gaussian: ℊ(xc) = 𝐴 ∙ 𝑒&)$%$#&ℊ

*"

(2)

• Asymmetric: ℊℓ(xc) = 𝐴 ∙ %ℓ(𝑥 > 𝑥+ , Γℓ)ℊ-𝑥 < 𝑥+ , Γℊ/

0 (3)

• Logistic: S(xc) = !.(/%(($%$#)

where k ∝ Γ (4)

Silva, Srimath, et al have recently demonstrated that the hybrid Frenkel-Wannier nature of excitons in 2D

lead iodide perovskites necessitates additional parameters due to exciton-lattice coupling in order to

properly model the exciton fine structure.7 The bound state contribution αexc was modeled with

expressions for the 1s exciton and the higher exciton series, with a factor u to correct for dielectric

confinement effects on the oscillator strength. For the undoped sample, the exciton fine structure

was adequately captured with two peaks centered at E1s,a and E1s,b, but for doped samples, a single

asymmetric peak centered at E1s was sufficient. The expressions are given below:

𝛼!" = #𝐴!ℓ&𝐸!",$( + 𝐴!ℊℓ&𝐸!",%(whenx=0eqTCBQ𝐴!ℊℓ(𝐸!")whenx=0.5to1eqTCBQ

(5)

𝛼01 = ∑ 2∙!+30&. 45 6

, ℊ(𝐸01)7084 for𝑚 > 1 (6)

The continuum absorption was modeled as a logistic function centered at the continuum onset

energy Eg added to the sum of three Gaussian peaks (with regular energy spacing δ and common

linewidth) to describe the continuum structure:

𝛼&'( = 𝐴)𝑆(𝐸*) + ∑ 𝐴+ℊ(𝐸, + 2(𝑙 − 1) ∙ 𝛿)-+.! (7)

Each peak center was fit by imposing the condition E1s < E2s < E3s < E4s < Eg < Ew. Eg was

also bound by 2.99 eV ± 0.05 eV in accordance with studies on similar materials as discussed

previously. Sample energy values obtained for the exciton series are plotted vs principal quantum

number m below for a fit of the undoped sample at 30 K, in addition to the calculated effective

dielectric constants, both of which agree with theoretical predictions on 2D materials.10

49

Supplementary Figure 33. Representative spectral decomposition of the absorption spectrum of Compound 2 (x = 0 eq TCBQ) at 30 K. (a) 1s exciton feature and its associated fine structure; (b) exciton Rydberg states 2s, 3s, and 4s; (c) onset of band edge continuum absorption; (d) absorption features attributed to the lead iodide continuum band structure.

Supplementary Figure 34. Left panel: Excitonic series (Ems) as a function of principal quantum number m, with the continuum onset shown as a dotted line. Right panel: Calculated effective dielectric constants for the exciton series, assuming a value for μexc of 0.22m0.15

50

Results of Markov chain Monte Carlo (MCMC) fitting

The absorption spectra for films of 2 with varying amounts of TCBQ could be fit at all

temperatures with the above model, which was implemented in a custom MATLAB script using a

Markov Chain Monte Carlo algorithm (MCMC). There is correlation between the parameters of

the higher order exciton, band onset, and fine structure peaks. As such, a local solution algorithm

(e.g. Levenberg-Marquardt) is subject to trapping in local solutions and is sensitive to the initial

guess and bounds used. The MCMC algorithm is used to avoid solutions trapped at local minima,

sampling instead from the underlying parameter distribution in the vicinity of the best-fit solution

to yield uncertainties reflective of data quality and model resolution. A detailed discussion of this

computational approach can be found in Ashner, Tisdale et al.16

At each temperature, the algorithm first generates 200 individual parameter sets, or

“walkers.” These walkers are allowed to explore a parameter space, with their movement directed

by the detailed balance condition, towards parameter values that better predict the data as measured

by the error weighted by the variance of the data at each point. This guarantees that the resulting

parameter distribution reflects the underlying parameter certainty as dictated by data quality and

model resolution. The walkers are allowed to move for 5000 steps each. At this point, all walkers

within 20% of the best performing parameter set are selected to restart the Markov chain for a

subsequent 10000 steps per walker. Upon reinitialization, this procedure discards any walkers

trapped in local minima. Parameter distributions are generated from the last 2500 steps per walker.

Central 95% credible regions are constructed for parameters at each temperature.

From the fit parameters, we can calculate the difference in energy between E1s and Eg for

all three samples from 6 K – 300 K as well as 95% credible regions at each temperature. All

temperature fits for each sample were averaged with weights based on the size of the 95% credible

region at that temperature, to obtain the values reported in the main text for Eb. This gives more

weight to the fits for which there is more certainty about the parameter values.

Corner plots can then be constructed in which the marginal and joint distributions of each

parameter are assessed for correlation. This was done for all parameters in the model. Selected

parameters relating to the exciton binding energy are plotted in Supplementary Figure 35. There

is a small degree of correlation between the higher exciton peak energies and Eg. This is not

surprising given our fit conditions that require E1s < E2s < E3s < E4s < Eg < Ew. However, the values

for Eg and E1 (with fine structure peaks centered at E1a and E1b) have no correlation.

51

Supplementary Figure 35. Corner plot of band gap (Eg) and exciton (Ems) peak energies of compound 2 with 0 eq TCBQ at 8 K. Along the main diagonal are the marginal distributions for each parameter, along with the mean value (black vertical line) and 95% central credible region (horizontal black line). The off-diagonal elements show the joint distributions for each pair of parameters. Uncorrelated parameters are evenly distributed around the joint mean. Diagonal distributions are present in the joint distribution plot when there is a degree of correlation between parameters. More elongated distributions show a higher amount of correlation.

52

G: ADDITIONAL SYNTHETIC INFORMATION AND CRYSTALLOGRAPHIC DETAIL

1. 1H and 13C NMR Data:

Nap-O-Bu-phthalimide (A):

53

Nap-O-Bu-NH3I (B):

54

Nap-O-Hex-phthalimide (C):

55

Nap-O-Hex-NH3I (D):

56

MeO-Nap-O-Et-BOC (E):

57

MeO-Nap-O-Et-NH3I (F)

58

MeO-Nap-O-Bu-Br (G):

59

MeO-Nap-O-Bu-phthalimide (H):

60

MeO-Nap-O-Bu-NH3I (I):

61

MeO-Nap-O-Hex-Br (J):

62

MeO-naphthalene-O-hexyl-pthalimide (K):

63

MeO-Nap-O-Hex-NH3I (L):

64

Cl5Ph-O-Pr-BOC (M):

65

Cl5Ph-O-Pr-NH3I (N):

66

2. High resolution mass spectrometry

Nap-O-Bu-phthalimide (A): HRMS (ESI-TOF) (M+Na)+ Expected 368.1257 Observed 368.1260

Nap-O-Bu-NH3I (B): HRMS (ESI-TOF) Expected 216.1383 Observed 216.1380

67

Nap-O-Hex-phthalimide (C): HRMS (ESI-TOF) (M+Na)+ Expected 396.1570 Observed 396.1569

Nap-O-Hex-NH3I (D): HRMS (ESI-TOF) Expected 244.1696 Observed 244.1694

68

MeO-Nap-O-Et-NH3I (F) HRMS (ESI-TOF) Expected 218.1176 Observed 218.1171

MeO-Nap-O-Bu-phthalimide (H): HRMS (ESI-TOF) (M+Na)+ Expected 398.1363 Observed 398.1365

69

MeO-Nap-O-Bu-NH3I (I): HRMS (ESI-TOF) Expected 246.1489 Observed 246.1491

MeO-naphthalene-O-hexyl-pthalimide (K): HRMS (ESI-TOF) (M+Na)+ Expected 426.1676 Observed 426.1683

70

MeO-Nap-O-Hex-NH3I (L): HRMS (ESI-TOF) Expected 274.1802 Observed 274.1806

Cl5Ph-O-Pr-BOC (M): HRMS (ESI-TOF) (M+Na)+ Expected 443.9465 Observed 443.9476

71

Cl5Ph-O-Pr-NH3I (N): HRMS (ESI-TOF) Expected 321.9121 Observed 321.9127

72

3. Justification for A and B level alerts:

3_H_Naphthalaene_Butyl_PbI4 (CCDC: 1934873)

PLAT241_ALERT_2_B High 'MainMol' Ueq as Compared to Neighbors of C25 Check

Room temperature data leads to uncertainty in exact centroid positions. This can be further parameterized and restrained but this masks innate diffuse disorder of atom position. PLAT342_ALERT_3_B Low Bond Precision on C-C Bonds ...............0.05929 Ang. Result of room temperature measurement and poor resolution of sample. This precision does not hinder the interpretation of results for this work.

PLAT987_ALERT_1_B The Flack x is >> 0 - Do a BASF/TWIN Refinement Please Check Attempted – did not improve Flack. No twin found via platon. 4_H_Naphthalene_Hexyl_PbI4 (CCDC 1934874) PLAT241_ALERT_2_B High 'MainMol' Ueq as Compared to Neighbors of C14 Check Room temperature data leads to uncertainty in exact centroid positions. This can be further parameterized and restrained but this masks innate diffuse disorder of atom position. PLAT241_ALERT_2_B High 'MainMol' Ueq as Compared to Neighbors of C28 Check Room temperature data leads to uncertainty in exact centroid positions. This can be further parameterized and restrained but this masks innate diffuse disorder of atom position. PLAT242_ALERT_2_B Low 'MainMol' Ueq as Compared to Neighbors of C27 Check Room temperature data leads to uncertainty in exact centroid positions. This can be further parameterized and restrained but this masks innate diffuse disorder of atom position. 5_MeO_Naphthalene_ethyl_PbI4 (CCDC 1934872)

PLAT342_ALERT_3_B Low Bond Precision on C-C Bonds ............... 0.03167 Ang. Result of room temperature measurement and poor resolution of sample. This precision does not hinder the interpretation of results for this work.

PLAT972_ALERT_2_B Check Calcd Resid. Dens. 1.30A From I2 -2.62 eA-3 Residual electron density off heavy element likely results from absorption of Cu radiation by heavy elements. Absorption correction was performed to minimize this and crystals diffracted too poorly under Mo radiation.

6_MeO_Naphthalene_butyl_PbI4 (CCDC 1934871)

THETM01_ALERT_3_A The value of sine(theta_max)/wavelength is less than 0.550 Calculated sin(theta_max)/wavelength = 0.5116

73

Despite long exposure time, no diffraction was observed past 0.98A and we are confident in the reported solution and refinement PLAT342_ALERT_3_B Low Bond Precision on C-C Bonds ............... 0.03214 Ang. Result of room temperature measurement and poor resolution of sample. This precision does not hinder the interpretation of results for this work.

7_MeO_Naphthalene_hexyl_PbI4 (CCDC 1934875)

PLAT234_ALERT_4_B Large Hirshfeld Difference C25 --C26 . 0.26 Ang. Room temperature data leads to uncertainty in exact centroid positions and thermal ellipsoid. This can be further parameterized and restrained but this masks innate diffuse disorder of atom position. PLAT241_ALERT_2_B High 'MainMol' Ueq as Compared to Neighbors of C13 Check Room temperature data leads to uncertainty in exact centroid positions. This can be further parameterized and restrained but this masks innate diffuse disorder of atom position. PLAT241_ALERT_2_B High 'MainMol' Ueq as Compared to Neighbors of C31 Check Room temperature data leads to uncertainty in exact centroid positions. This can be further parameterized and restrained but this masks innate diffuse disorder of atom position. PLAT342_ALERT_3_B Low Bond Precision on C-C Bonds ............... 0.03844 Ang. Result of room temperature measurement and poor resolution of sample. This precision does not hinder the interpretation of results for this work.

8_Cl5_Ph_Propyl_PbI4 (CCDC 1934876)

PLAT213_ALERT_2_B Atom C8 has ADP max/min Ratio ..... 4.3 prolat There is disorder in this alkyl chain that could not be readily modeled. The resulting electron density is represented by a large ellipsoid.

PLAT241_ALERT_2_B High 'MainMol' Ueq as Compared to Neighbors of C18 Check Room temperature data leads to uncertainty in exact centroid positions. This can be further parameterized and restrained but this masks innate diffuse disorder of atom position. PLAT342_ALERT_3_B Low Bond Precision on C-C Bonds ............... 0.04125 Ang. Result of room temperature measurement and poor resolution of sample. This precision does not hinder the interpretation of results for this work.

74

REFERENCES

1. Passarelli, J. V., et al., Enhanced out-of-plane conductivity and photovoltaic performance in n = 1 layered perovskites through organic cation design. J. Am. Chem. Soc. 140, 7313-7323 (2018). 2. Ikkanda, B. A., Samuel, S. A., Iverson, B. L., Ndi and dan DNA: Nucleic acid-directed assembly of ndi and dan. The Journal of organic chemistry 79, 2029-2037 (2014). 3. Jiang, Z., et al., The dedicated high-resolution grazing-incidence x-ray scattering beamline 8-id-e at the advanced photon source. Journal of synchrotron radiation 19, 627-636 (2012). 4. Kitazawa, N., Aono, M., Watanabe, Y., Temperature-dependent time-resolved photoluminescence of (c6h5c2h4nh3)2pbx4 (x=br and i). Material Chemistry and Physics 134, 875-880 (2012). 5. Younts, R., et al., Efficient generation of long-lived triplet excitons in 2d hybrid perovskite. Adv. Mater. (Weinheim, Ger.) 29, 1604278 (2017). 6. Yang, Y., et al., Low surface recombination velocity in solution-grown ch3nh3pbbr3 perovskite single crystal. Nature Communications 6, 7961 (2015). 7. Neutzner, S., et al., Exciton-polaron spectral structures in two-dimensional hybrid lead-halide perovskites. Physical Review Materials 2, 064605 (2018). 8. Tanaka, K., et al., Image charge effect on two-dimensional excitons in an inorganic-organic quantum-well crystal. Physical Review B 71, 045312 (2005). 9. Smith, M. D., et al., Decreasing the electronic confinement in layered perovskites through intercalation. Chemical Science 8, 1960-1968 (2017). 10. Blancon, J. C., et al., Scaling law for excitons in 2d perovskite quantum wells. Nature Communications 9, 2254 (2018). 11. García-Benito, I., et al., Fashioning fluorous organic spacers for tunable and stable layered hybrid perovskites. Chem. Mater. 30, 8211-8220 (2018). 12. Yaffe, O., et al., Excitons in ultrathin organic-inorganic perovskite crystals. Physical Review B 92, 045414 (2015). 13. Thygesen, K. S., Calculating excitons, plasmons, and quasiparticles in 2d materials and van der waals heterostructures. 2D Materials 4, 022004 (2017). 14. Chernikov, A., et al., Exciton binding energy and nonhydrogenic rydberg series in monolayer ws2. Phys. Rev. Lett. 113, 076802/1-076802/5, 5 pp. (2014). 15. Katan, C., Mercier, N., Even, J., Quantum and dielectric confinement effects in lower-dimensional hybrid perovskite semiconductors. Chem. Rev. 119, 3140-3192 (2019). 16. Ashner, M. N., Winslow, S. W., Swan, J. W., Tisdale, W. A., Markov chain monte carlo sampling for target analysis of transient absorption spectra. The Journal of Physical Chemistry A 123, 3893-3902 (2019).

tunable exciton binding energy in 2d hybrid layered perovskites …10.1038... · 2020-06-25 ·...

Documents