research article improved composite gel electrolyte by...

Research ArticleImproved Composite Gel Electrolyte by Layered Vermiculite forQuasi-Solid-State Dye-Sensitized Solar Cells

Hongcai He1 Shuangshuang Ren1 Deting Kong1 and Ning Wang12

1 State Key Laboratory of Electronic Thin Films and Integrated Devices and School of Microelectronics and Solid-State ElectronicsUniversity of Electronic Science and Technology of China Chengdu 610054 China

2 Institute of Electronic and Information Engineering University of Electronic Science and Technology of ChinaDongguan 523808 China

Correspondence should be addressed to Hongcai He hehcuestceducn

Received 12 March 2014 Accepted 30 March 2014 Published 22 April 2014

Academic Editor Ke Sun

Copyright copy 2014 Hongcai He et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

A composite quasisolid electrolyte is prepared by adding a layered vermiculite (VMT) into the iodidetriiodide electrolyte including4-tert-butylpyridine which obviously improves the photovoltaic properties of quasisolid dye-sensitized solar cells (DSSCs) Whenadding 6wt VMT the maximum photovoltaic conversion efficiency of 389 is obtained which reaches more than two timesgreater than that without VMTThis enhancement effect is primarily explained by studying the Nyquist spectra dark currents andphotovoltaic conversion efficiency

1 Introduction

Dye-sensitized solar cells (DSSCs) have attracted an ever-increasing attention since reported by OrsquoRegan and Gratzelin 1991 [1] for its low-cost environmental friendliness andpotential high conversion efficiency which was consideredto be a strong contender of the next-generation solar cells inthe near future Generally a mainstream DSSC is composedof three main parts a dye-adsorbed porous nanocrystallineTiO2film supported on a transparent conducting glass as

the photoanode an organic liquid electrolyte essentiallycontaining an iodidetriiodide redox couple and a platinizedtransparent glass substrate as the counter electrode Thesethree layers are sandwiched together Electrolytes play animportant role in the DSSCs as the charge exchange mediumThe organic liquid electrolyte was commonly used in tra-ditional DSSCs which is associated with problems such ashermetic sealing of the cell solvent volatilization and leakagebad long-term stability decomposing dye and corroding Ptelectrode

Recently many efforts have been made to overcomethe above problems of traditional DSSCs with liquid elec-trolytes and solid-state and quasi-solid-state DSSCs havebeen intensely studied with various approaches Some novel

technologies and materials including p-type semiconductors[2] organic and inorganic holes conductors [3] and polymergel electrolytes [4 5] were used in new electrolytes toimprove properties Among them polymer based quasi-solid-state electrolytes are a very good choice for its highionic conductivity long-term stability good interfacial fillingproperties and inhibiting leakage which commonly have apolymer and ionic liquid electrolytes containing dispersednanocomponents Some ceramic nanoparticles such as SiO

2

[6] TiC [7] and TiN [8] were added into ionic liquids-based electrolytes for DSSCs and an enhanced conversionefficiency was obtained In our previous work [9 10] somelayered materials such as 120572-zirconium phosphate and Mg-Alhydrotalcite were added into the iodidetriiodide ionic liquidto prepare quasi-solid-state electrolytes which obviouslyimproves the photovoltaic properties of quasisolid DSSCsVermiculite (VMT) is not only a layered mica-type silicatebut is also with a large surface area and strong absorptivecapacity and has often been studied for the preparationof composites [11 12] In this paper a new composite gelpolymer electrolyte was prepared by adding vermiculite(VMT) powder into iodide-based liquid electrolyte withthe addition of 4-tert-butylpyridine (TBP) propylene car-bonate (PC) and poly (ethylene oxide) (PEO-600000)

Hindawi Publishing CorporationAdvances in Condensed Matter PhysicsVolume 2014 Article ID 521493 5 pageshttpdxdoiorg1011552014521493

2 Advances in Condensed Matter Physics

Glass

Platinized TCO electrode

Glass

Electrolyte

Figure 1 Schematic diagram of the experimental thin-layer cellconfiguration employed for the electrochemical measurements

The electrochemical properties of the composite electrolytewere analyzed systematically by testing Nyquist diagram anda typical DSSC was packaged with the new quasi-solid-statecomposite electrolyte to measure photovoltaic properties

2 Experimental

21 Preparation of VMT and Composite Gel Polymer Elec-trolyte The startingVMTwas supplied by BrightMining Co(Shanghai China) After VMT was ball-milled for 6 h in thesolvent of deionized water the ultrasonic irradiation methodreported by Nguyen et al [13] was used to prepare the layeredvermiculite (VMT) powders

Then VMT powders with the contents of 0wt 3 wt6wt 9wt and 12wt relative to the weight of TBPwere added to the iodide-based gel polymer electrolyte pre-pared according to [14] which contained 05MLiI 005M I

2

6mLPC 05MTBP 04 g PEO-600000 and acetonitrile sol-vent After stirring strongly for 72 h at 80∘C the composite gelpolymer electrolytes including layered VMT were obtained

22 Testing Device and Characterization Method X-raydiffraction (XRD Rigaku Dmax-RB) with CuKa radiationwas used for phase analysis of the powders under 40 kVand 30mA Scanning electronmicroscopy (SEM INSPECTFFEI Netherlands) was used to observe the micrographsSimple thin-layer cells were manufactured to measure ACimpedance according to [15] The cell was made up of twoidentical platinized TCO-coated glass substrates separatedby Surlyn thermal packaging adhesive and filled with thecomposite electrolyte with VMT additives as shown inFigure 1 The active area of the electrodes was about 016 cm2and the distance between the electrodes was about 25120583mElectrochemical impedance spectra (EIS) were obtained byusing CHI660c electrochemical analyzer (CH InstrumentCo ltd China) Sinusoidal perturbations of 10mV at fre-quencies from 001Hz to 100 kHz with zero bias potentialwere applied on thin-layer cells with a two-electrode modeas shown in Figure 1 In order to study the photovoltaicproperties of the DSSCs with the composite electrolytescontaining VMT quasisolid DSSCs were packaged accordingto the previous published procedures [9 10] from dye-coatedTiO2film photoanodes counterelectrodes (500 nm thick

Pt) and composite gel polymer electrolytes containing VMTPhotovoltaic properties were measured at 100mWcmminus2 lightintensity under AM 15 irradiation of xenon lamp while the

Figure 2 SEM micrograph of VMT powder

10 20 30 40 50

2120579 (∘)

Inte

nsity

(au

)

(a)

(b)

(c)

(200)

Figure 3 X-ray diffraction patterns of (a) VMT powder (b)the composite electrolyte membrane with 6wt VMT (c) thecomposite electrolyte membrane with 0wt VMT

dark current density is measured in dark All measurementswere carried out at room temperature

3 Results and Discussion

31 Analysis of VMT Powders Figure 2 shows a SEM micro-graph of VMT powders and the layered structure with ananoscale layer thickness can be observed X-ray diffrac-tion patterns of the prepared VMT powder and compositeelectrolytes are shown in Figure 3 As shown in Figure 3(a)the prepared VMT powders are well-crystallized with thestrongest diffraction peaks at 896∘ indexed as (200) peak[13] After 6wt VMT additive was mixed into iodine-basedPEO electrolyte and coated on the photoanode thin filmthe (200) peak was still detected in the obtained electrolytemembrane as shown in Figure 3(b)

32 The Influence of VMT on the Conductivity The Nyquistspectra of thin-layer cells with composite gel iodide-basedelectrolytes containing different contents of VMT are shown

Advances in Condensed Matter Physics 3

0 10 20 30 40 50 60

Z998400 (ohm)

0

2

4

6

8

10

12

14

minusZ998400998400

(ohm

)

0wt3wt6wt

9wt12wt

Rct Rct

ZCPEZCPE

Rs

Zw

Figure 4 Nyquist diagram of thin-layer cells with various contentsof VMT and the inset shows the equivalent circuit

Table 1 The results for the 119877ct and corresponding 120590 of the iodide-based gel electrolytes with various contents of VMT

VMT (wt) 119877ct (Ω) 119877119904(Ω) 120590 (10minus4 S cmminus1)

0 3204 1369 11413 1505 911 17156 835 575 27179 1347 785 199112 1964 1163 1344

in Figure 4 The equivalent circuit is shown as the inset ofFigure 4 Each curve is composed of two semicirclesThe onein the high frequency region represents the charge transferresistance (119877ct) of Ptelectrolyte interface and the other onein the low frequency region relates to theWarburg impedance(119885119908) [8] 119877

119904is the ohmic serial resistance and 119885CPE is the

impedance of electrical double layer Based on the equivalentcircuit the fitting data of the charge transfer resistance (119877ct)and the ohmic serial resistance (119877

119904) were obtained Then the

ion conductivity of the electrolyte (120590) can be obtained fromthe equation 120590 = 119897(119877

119904119886) [4] where 119886 are 119897 are the active

area of the electrodes (here 119886 = 016 cm2) and the distancebetween electrodes (here 119897 = 025 120583m) respectively Theresults for the 119877ct values and 119877119904 values and corresponding 120590values of iodide-based gel electrolytes with various contentsof VMT are summarized in Table 1

As shown in Figure 4 and Table 1 the 119877ct values andthe 119877119904values of the cells decrease markedly and the corre-

sponding 120590 values increase with adding VMT up to 6wtHere VMT as dispersed second phase insulating particlesaffected drastically the conductivities of composite iodide-based gel electrolytes Quite a few works [16 17] reportedthe effect of dispersed second phase particles on the ionic

Table 2 The photovoltaic parameters of the DSSCs with variouscontents of VMT

VMT (wt) 119869sc (mA cmminus2) 119881oc (V) FF 120578 ()0 508 062 054 1703 907 064 053 3076 977 067 059 3899 853 066 055 31012 715 064 053 243

conduction When adding the insulating phase in the ion-conductive phase ionic conductivity will first increase andthen decrease Nan developed an improved and simple self-consistent effective-medium theory to explain the effect [18]It has now become widely accepted that the enhancementeffect of conductivity is related to creating highly conductivepaths along the interfaces between the electrolyte matrixand the second phase grains [18] The highly conductivepaths can be an interfacial layer with high concentrationsof defects a space charge layer andor an absorbed waterlayer VMT has a layered structure with a large surface areawhich means there is enough interface to create conductivepaths When the content of VMT is 6wt the minimum119877ct value of 835Ω and the minimum 119877

119904value of 575Ω are

obtained correspondingwith themaximum120590 value of 2717lowast10minus4 S cmminus1 While the content of VMT is over 6wt theinert second phase particles directly contact each other toform continuumpercolation net clusters which tends to limition movement and decrease the conductivity [17 18] and asa result the 119877ct values and the 119877

119904value increase and the 120590

values decrease markedly

33The Influence of VMT on the Photovoltaic Conversion Effi-ciency Figure 5(a) is the 119869-119881 curves of thin-layer cells withvarious VMT contents The results for short-circuit currentdensity (119869sc) open circuit potential (119881oc) fill factor (FF) andconversion efficiency (120578) of the DSSCs with different addi-tions of VMT are summarized in Table 2TheDSSCs with theelectrolytes addingVMT show a higher open circuit potential(119881oc) and significantly higher short current density (119869sc) thanthat without adding VMT 119881oc and 119869sc increase first and thendecrease with the increase of VMT contents In order to studythe influence of electrolytes with adding various contents ofVMT on the above photoelectric properties the dark currentdensity-voltage curves of the DSSCs with various contentsof VMT are shown in Figure 5(b) It can be easily foundthat the dark current density decreases when adding theVMT As the content of VMT increases to 6wt the darkcurrent density of the DSSC is suppressed to a minimum andincreases quickly as the content of VMT further increasesover 6wt to 12wt

The change in both 119881oc and 119869sc of the DSSCs is relatedto the dark current density The enhanced 119881oc is due tothe suppression of the dark current in the TiO

2electrolyte

interfaceThe fact that the onset of the dark current of DSSCsoccurs at the higher forward bias indicates the lower 119868minus

3

reduction rate (119896et) [9 19] The decrease of 119868minus3reduction rate


00 01 02 03 04 05 06 07

Voltage (V)

Curr

ent d

ensit

y (m

Ac

m2 )

0

2

4

6

8

10

12

14

0wt3wt6wt

9wt12wt

(a)

00

minus05

minus10

minus15

minus20

00 02 04 06 08 10

Curr

ent d

ensit

y (m

Ac

m2 )

Voltage (V)

0wt3wt6wt

9wt12wt

(b)

Figure 5 The 119869-119881 curves of DSSCs with composite electrolytes containing various contents of VMT (a) under simulated AM 15 solarspectrum irradiation at 100mW cmminus2 (b) in the dark

will lead to an increase of 119881oc according to the followingequation [19]

119881oc =119896119879

119890

ln(119868inj

119899cb119896et [119868minus

3]

) (1)

where 119868inj 119899cb and 119896et are the flux of charge originating fromsensitized injection related to the electron back transfer ratethe concentration of electrons at the TiO

2surface and the

rate constants for 119868minus3reduction respectively As shown in

Figure 5(b) the onset of the dark current of DSSCs occursat 227 335 378 325 and 319mV with various electrolytesadding 0wt 3wt 6wt 9wt and 12wt of VMTrespectively The higher onset voltage value of the darkcurrent of DSSCs with adding VMT than that without addingVMT reveals that VMT can efficiently suppress the darkreaction to obtain higher 119881oc On the other hand the 119869scof DSSCs is also associated with the dark current whichcan be given by the equation 119869sc = 119869inj minus 119869rec where119869inj and 119869rec are the electron injection current density andthe recombination current density respectively [20] Theelectron injection current density should be constant sinceall the DSSCs have the same electrodes and experimentalconditions The recombination current mainly manifests asthe dark current so the recombination current density hassimilar variation trend with the dark current density [21]Consequently 119869sc increases with the decrease of the darkcurrent density As a consequence proper addition of VMTcan improve both 119869sc and 119881oc of the DSSC and the bestratio is about 6wt of VMT When the content of VMT is6wt the conversion efficiency (120578) is up to the maximum of389which ismore than two times greater than thatwithout

adding VMT While the content of VMT is over 6wt theconversion efficiency (120578) decreases quickly

4 Conclusions

In summary we prepared a quasi-solid-state compositeelectrolyte by adding layered vermiculite (VMT) powder intothe iodide-based electrolyte including PC TBP and PEO-600000 Electrochemical analysis was done on the DSSCswith various electrolytes adding different contents of VMTThe results showed that VMT as a dispersed second phaseinsulating particles affected drastically the conductivities ofcomposite electrolytes The reduction of the dark currentdensity with adding VMT indicated that the 119869sc and 119881ocincreased with the addition of appropriate amount of VMTcompared toDSSCswithoutVMTWhen the content ofVMTreached 6wt the conversion efficiency (120578) was maximizedto 389 which was more than two times greater than thatwithout addition of the VMT

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was supported by Natural Science Foundationof China (51272035 51272037 and 51362026) InternationalCooperationMOST-JST Program Fund (no 2010DFA61410)The Project of International Cooperation of the Ministry ofScience and Technology of China (no 2011DFA50530)


and Scientific Research Project of Guangdong (no2012B091000015)

References

[1] B OrsquoRegan and M Gratzel ldquoA low-cost high-efficiency solarcell based on dye-sensitized colloidal TiO

2filmsrdquo Nature vol

353 no 6346 pp 737ndash740 1991[2] K Tennakone G K R Senadeera D B R A De Silva and I R

MKottegoda ldquoHighly stable dye-sensitized solid-state solar cellwith the semiconductor 4CuBr 3S(C

4H9)2as the hole collectorrdquo

Applied Physics Letters vol 77 no 15 pp 2367ndash2369 2000[3] C S Karthikeyan H Wietasch and M Thelakkat ldquoHighly

efficient solid-state dye-sensitized TiO2solar cells using donor-

antenna dyes capable of multistep charge-transfer cascadesrdquoAdvanced Materials vol 19 no 8 pp 1091ndash1095 2007

[4] X Chen Q Li J Zhao et al ldquoIonic liquid-tethered nanopar-ticlepoly(ionic liquid) electrolytes for quasi-solid-state dye-sensitized solar cellsrdquo Journal of Power Sources vol 207 pp 216ndash221 2012

[5] P Wang S M Zakeeruddin J E Moser M K NazeeruddinT Sekiguchi and M Gratzel ldquoA stable quasi-solid-state dye-sensitized solar cell with an amphiphilic ruthenium sensitizerand polymer gel electrolyterdquo Nature Materials vol 2 no 6 pp402ndash407 2003

[6] K-M Lee P-Y Chen C-P Lee and K-C Ho ldquoBinary room-temperature ionic liquids based electrolytes solidified with SiO

2

nanoparticles for dye-sensitized solar cellsrdquo Journal of PowerSources vol 190 no 2 pp 573ndash577 2009

[7] C-P Lee K-M Lee P-Y Chen andK-C Ho ldquoOn the additionof conducting ceramic nanoparticles in solvent-free ionic liquidelectrolyte for dye-sensitized solar cellsrdquo Solar Energy Materialsand Solar Cells vol 93 no 8 pp 1411ndash1416 2009

[8] C-P Lee L-Y Lin R Vittal and K-C Ho ldquoFavorable effectsof titanium nitride or its thermally treated version in a gelelectrolyte for a quasi-solid-state dye-sensitized solar cellrdquoJournal of Power Sources vol 196 no 3 pp 1665ndash1670 2011

[9] N Wang H Lin J Li and X Li ldquoImproved quasi-soliddye-sensitized solar cells by composite ionic liquid electrolyteincluding layered 120572 -zirconium phosphaterdquo Applied PhysicsLetters vol 89 no 19 Article ID 194104 2006

[10] H He J Zhu N Wang F Luo and K Yang ldquoComposite gelpolymer electrolytes containing layered Mg-Al hydrotalcite forquasi-solid dye-sensitized solar cellsrdquo Journal of the Electro-chemical Society vol 161 pp H17ndashH20 2014

[11] M V Smalley H L M Hatharasinghe I Osborne J Swensonand S M King ldquoBridging flocculation in vermiculitemdashPEOmixturesrdquo Langmuir vol 17 no 13 pp 3800ndash3812 2001

[12] L Zang J Luo J Guo H Liu and J Ru ldquoPreparation andcharacterization of poly(ethylene glycol)organo- vermiculitenanocomposite polymer electrolytesrdquo Polymer Bulletin vol 65no 7 pp 669ndash680 2010

[13] A N Nguyen L Reinert J M Leveque et al ldquoPreparation andcharacterization of micron and submicron-sized vermiculitepowders by ultrasonic irradiationrdquoApplied Clay Science vol 72pp 9ndash17 2013

[14] Y Ren Z Zhang S Fang M Yang and S Cai ldquoApplication ofPEO based gel network polymer electrolytes in dye-sensitizedphotoelectrochemical cellsrdquo Solar Energy Materials and SolarCells vol 71 no 2 pp 253ndash259 2002

[15] N Papageorgiou W F Maier and M Gratzel ldquoAniodinetriiodide reduction electrocatalyst for aqueous andorganic mediardquo Journal of the Electrochemical Society vol 144no 3 pp 876ndash884 1997

[16] C C Liang ldquoConduction characteristics of the lithium iodidemdashaluminum oxide solid electrolytesrdquo Journal of the Electrochemi-cal Society vol 120 no 10 pp 1289ndash1292 1973

[17] C-W Nan L Fan Y Lin and Q Cai ldquoEnhanced ionicconductivity of polymer electrolytes containing nanocompositeSiO2particlesrdquo Physical Review Letters vol 91 no 26 pp

2661041ndash2661044 2003[18] C-W Nan ldquoPhysics of inhomogeneous inorganic materialsrdquo

Progress in Materials Science vol 37 no 1 pp 1ndash116 1993[19] M K Nazeeruddin A Kay I Rodicio et al ldquoConver-

sion of light to electricity by cis-X2bis(221015840-bipyridyl-441015840-dicarboxylate)ruthenium(II) charge-transfer sensitizers (X =Cl- Br- I- CN- and SCN-) on nanocrystalline TiO

2elec-

trodesrdquo Journal of the American Chemical Society vol 115 no14 pp 6382ndash6390 1993

[20] L Y Chen and Y T Yin ldquoThe influence of length of one-dimensional photoanode on the performance of dye-sensitizedsolar cellsrdquo Journal of Materials Chemistry vol 22 no 47 pp24591ndash24596 2012

[21] K Guo M Li X Fang et al ldquoPreparation and enhancedproperties of dye-sensitized solar cells by surface plasmonresonance of Ag nanoparticles in nanocomposite photoanoderdquoJournal of Power Sources vol 230 pp 155ndash160 2013

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

High Energy PhysicsAdvances in

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


FluidsJournal of

Atomic and Molecular Physics

Journal of



Advances in Condensed Matter Physics

OpticsInternational Journal of



AstronomyAdvances in

International Journal of


Superconductivity


Statistical MechanicsInternational Journal of


GravityJournal of


AstrophysicsJournal of


Physics Research International


Solid State PhysicsJournal of

Computational Methods in Physics

Journal of



Soft MatterJournal of

Hindawi Publishing Corporationhttpwwwhindawicom

AerodynamicsJournal of

Volume 2014


PhotonicsJournal of


Journal of

Biophysics


ThermodynamicsJournal of


Glass

Platinized TCO electrode

Glass

Electrolyte

Figure 1 Schematic diagram of the experimental thin-layer cellconfiguration employed for the electrochemical measurements

The electrochemical properties of the composite electrolytewere analyzed systematically by testing Nyquist diagram anda typical DSSC was packaged with the new quasi-solid-statecomposite electrolyte to measure photovoltaic properties

2 Experimental

21 Preparation of VMT and Composite Gel Polymer Elec-trolyte The startingVMTwas supplied by BrightMining Co(Shanghai China) After VMT was ball-milled for 6 h in thesolvent of deionized water the ultrasonic irradiation methodreported by Nguyen et al [13] was used to prepare the layeredvermiculite (VMT) powders

Then VMT powders with the contents of 0wt 3 wt6wt 9wt and 12wt relative to the weight of TBPwere added to the iodide-based gel polymer electrolyte pre-pared according to [14] which contained 05MLiI 005M I

2

6mLPC 05MTBP 04 g PEO-600000 and acetonitrile sol-vent After stirring strongly for 72 h at 80∘C the composite gelpolymer electrolytes including layered VMT were obtained

22 Testing Device and Characterization Method X-raydiffraction (XRD Rigaku Dmax-RB) with CuKa radiationwas used for phase analysis of the powders under 40 kVand 30mA Scanning electronmicroscopy (SEM INSPECTFFEI Netherlands) was used to observe the micrographsSimple thin-layer cells were manufactured to measure ACimpedance according to [15] The cell was made up of twoidentical platinized TCO-coated glass substrates separatedby Surlyn thermal packaging adhesive and filled with thecomposite electrolyte with VMT additives as shown inFigure 1 The active area of the electrodes was about 016 cm2and the distance between the electrodes was about 25120583mElectrochemical impedance spectra (EIS) were obtained byusing CHI660c electrochemical analyzer (CH InstrumentCo ltd China) Sinusoidal perturbations of 10mV at fre-quencies from 001Hz to 100 kHz with zero bias potentialwere applied on thin-layer cells with a two-electrode modeas shown in Figure 1 In order to study the photovoltaicproperties of the DSSCs with the composite electrolytescontaining VMT quasisolid DSSCs were packaged accordingto the previous published procedures [9 10] from dye-coatedTiO2film photoanodes counterelectrodes (500 nm thick

Pt) and composite gel polymer electrolytes containing VMTPhotovoltaic properties were measured at 100mWcmminus2 lightintensity under AM 15 irradiation of xenon lamp while the

Figure 2 SEM micrograph of VMT powder

10 20 30 40 50

2120579 (∘)

Inte

nsity

(au

)

(a)

(b)

(c)

(200)

Figure 3 X-ray diffraction patterns of (a) VMT powder (b)the composite electrolyte membrane with 6wt VMT (c) thecomposite electrolyte membrane with 0wt VMT

dark current density is measured in dark All measurementswere carried out at room temperature

3 Results and Discussion

31 Analysis of VMT Powders Figure 2 shows a SEM micro-graph of VMT powders and the layered structure with ananoscale layer thickness can be observed X-ray diffrac-tion patterns of the prepared VMT powder and compositeelectrolytes are shown in Figure 3 As shown in Figure 3(a)the prepared VMT powders are well-crystallized with thestrongest diffraction peaks at 896∘ indexed as (200) peak[13] After 6wt VMT additive was mixed into iodine-basedPEO electrolyte and coated on the photoanode thin filmthe (200) peak was still detected in the obtained electrolytemembrane as shown in Figure 3(b)

32 The Influence of VMT on the Conductivity The Nyquistspectra of thin-layer cells with composite gel iodide-basedelectrolytes containing different contents of VMT are shown


0 10 20 30 40 50 60

Z998400 (ohm)

0

2

4

6

8

10

12

14

minusZ998400998400

(ohm

)

0wt3wt6wt

9wt12wt

Rct Rct

ZCPEZCPE

Rs

Zw




0 3204 1369 11413 1505 911 17156 835 575 27179 1347 785 199112 1964 1163 1344



















2electrolyte


3



00 01 02 03 04 05 06 07

Voltage (V)

Curr

ent d

ensit

y (m

Ac

m2 )

0

2

4

6

8

10

12

14

0wt3wt6wt

9wt12wt

(a)

00

minus05

minus10

minus15

minus20

00 02 04 06 08 10

Curr

ent d

ensit

y (m

Ac

m2 )

Voltage (V)

0wt3wt6wt

9wt12wt

(b)



119881oc =119896119879

119890

ln(119868inj

119899cb119896et [119868minus

3]

) (1)


2surface and the




4 Conclusions




Acknowledgments




References












2
















2elec-









FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




0 10 20 30 40 50 60

Z998400 (ohm)

0

2

4

6

8

10

12

14

minusZ998400998400

(ohm

)

0wt3wt6wt

9wt12wt

Rct Rct

ZCPEZCPE

Rs

Zw




0 3204 1369 11413 1505 911 17156 835 575 27179 1347 785 199112 1964 1163 1344



















2electrolyte


3



00 01 02 03 04 05 06 07

Voltage (V)

Curr

ent d

ensit

y (m

Ac

m2 )

0

2

4

6

8

10

12

14

0wt3wt6wt

9wt12wt

(a)

00

minus05

minus10

minus15

minus20

00 02 04 06 08 10

Curr

ent d

ensit

y (m

Ac

m2 )

Voltage (V)

0wt3wt6wt

9wt12wt

(b)



119881oc =119896119879

119890

ln(119868inj

119899cb119896et [119868minus

3]

) (1)


2surface and the




4 Conclusions




Acknowledgments




References












2
















2elec-









FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics




00 01 02 03 04 05 06 07

Voltage (V)

Curr

ent d

ensit

y (m

Ac

m2 )

0

2

4

6

8

10

12

14

0wt3wt6wt

9wt12wt

(a)

00

minus05

minus10

minus15

minus20

00 02 04 06 08 10

Curr

ent d

ensit

y (m

Ac

m2 )

Voltage (V)

0wt3wt6wt

9wt12wt

(b)



119881oc =119896119879

119890

ln(119868inj

119899cb119896et [119868minus

3]

) (1)


2surface and the




4 Conclusions




Acknowledgments




References












2
















2elec-









FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics





References












2
















2elec-









FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics








FluidsJournal of


Journal of










Superconductivity




GravityJournal of








Journal of






Volume 2014


PhotonicsJournal of


Journal of

Biophysics



research article improved composite gel electrolyte by...

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