Supporting Information

Core-shell like glass containing lanthanide doped nanocrystals for

efficient luminescence

Qunhuo Liu,a Ying Tian,* a Zhen Xiao, a Jiawei Zhang, a Wenhua Tang, a Xufeng Jing, b Junjie Zhang a and Shiqing Xu* a

a.College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018, China.

b. Institute of Optoelectronic Technology, China Jiliang University, Hangzhou 310018, China.

† Email: tianyingcjlu@163.com, sxucjlu@163.com.

Experimental ProceduresReagents. TeO2(99.99%), ZnO(99.99%), Na2CO3(99.99%), Yb2O3(99.99%), Er2O3(99.99%), Yb(NO3)3(99.9%) and Ho(NO3)3 (99.99%) were purchased from Aladdin Industrial Corporation(Shanghai, China). H3BO3(99.8%) and potassium hydroxide (KOH) were purchased form Sinopharm Chemical Reagent Co., Ltd(Shanghai, China). TiO2 was purchased from Acros organics(USA). Sr(NO3)2(99.0%) was purchased from Tianjing Bo Di Chemical Co., Ltd(Tianjing, China). All raw materials were used as received without further purification.Nanocrystals Synthesis Methods. SrTiO3 nanocrystals were synthesized by hydrothermal reaction method. In a typical experiment, KOH was used as mineralizer. Dissolve 5mmol of Sr(NO3)2, 10mol% Yb(NO3)3 and 2 mol% Ho(NO3)3•5H2O in 10 mL of deionized water with stirring until completely dissolved. With a magnetic stirrer, 0.15mol of KOH was fully dissolved in 20 mL of deionized water, then 5mmol of TiO2 was slowly added to the KOH solution and stirring continued for 4 hours. The resulting precursor mixture was then carefully poured into a 50 mL Teflon liner. The liner into the autoclave sealed, the use of hydrothermal reaction characteristics

of high temperature and pressure in the blast oven for 12h at 180℃ hydrothermal treatment. By the time the oven temperature was lowered to room temperature, the hydrothermal reaction product was washed alternately with water and ethanol and placed in a blast drying oven for 12h at 80℃. Finally, the obtained nanocrystals were sintering at 650℃ for 2h to conduct phase transformation.Glass Fabrication Methods. The high temperature melting-quenching method was used to fabricate TZNB glass billets with moral composition 70TeO2-15ZnO-10Na2O-5B2O3. For TZNB glass containing SrTiO3 nanocrystals, 10g glass batch was melted in a pit furnace in ambient atmosphere at 800℃ for 25min. Subsequently, the glass melt temperature was decreased to 650℃ and maintained at 650℃ for 5min. 0.02g dried SrTiO3 nanocrystals were added into the glass melt and the mixture was melted for 5min more. 2.5min after doping of the nanocrystals, the melt in the crucible was manually swirled to disperse doped nanocrystals. Then the melt was quenched on a preheated brass mold before being annealed at 300℃ for 2h to release the inner stress. Finally, the prepared glass was cut and polished to 10×10×1.5mm for spectroscopic

Electronic Supplementary Material (ESI) for ChemComm.This journal is © The Royal Society of Chemistry 2018

measurement, and grinded as powders for thermal and structural measurement. To avoid the influence of two-temperature glass melting process on glass structure, blank

TZNB glass was also melted at 800℃ for 25min and 650℃ for 5min. In the process of preparing Yb/Ho NCs-doped TZNB glass, 0.02g Yb/Ho NCs were added. In

the process of preparing Yb/Er ions and Yb/Ho NCs-codoped TZNB glass, 0.02g Yb2O3, 0.001g Er2O3 and 0.02g Yb/Ho NCs were added. In the process of preparing Yb/Ho ions codoped TZNB glass (Yb/Er/Ho ions codoped TZNB glass) , 0.2g Yb2O3 and 0.01g Ho2O3 (and 0.01g Er2O3) were added. In the process of preparing high concentration rare earths doped samples, 0.5g Yb2O3, 0.025g Er2O3 (and 0.025g Ho2O3 or 0.5g SrTiO3 NCs) were added for Yb/Er ions codoped glass (Yb/Er/Ho ions codoped glass or Yb/Er ions + Yb/Ho SrTiO3 NCs codoped glass, respectively). Characterization. Differential scanning calorimetry (DSC) measurements were conducted on a differential thermal analysis (DTA 404PC, NETZSCH, Germany) at the heating rate of 10 K/min. Powder X-ray diffraction (XRD) measurements were carried out on a X-ray diffractometer(D2 PHASER, Bruker, Germany) using Cu-Kα1 radiation. Morphological features of SrTiO3 nanocrystals were investigated using a field emission scanning electron microscope (SEM) (SU8010, HITACHI, Japan) operating at 10.0kV. Raman spectra were performed on a Raman spectrometer (inVia, Renishaw, UK) excited by 532 nm laser. Upconversion spectra were recorded on a fluorescence spectrometer-Fluorolog (Fl-3-211, Jobin Yvon, France). 1.5μm and 2μm emissions spectra and decay curves were studied on a MIR emission spectrometer (FLS980, Edinburgh Instruments Ltd, UK) and detected with a liquid nitrogen-cooled PbS detector.

Fig.S1 XRD pattern of prepared SrTiO3 nanocrystals

Fig. S2 SEM image of SrTiO3 nanocrystals.

Fig. S3 Decay curve of Yb/Er ions codoped TZNB at 1550nm

Fig.S4 Decay curve of Yb/Er/Ho ions codoped TZNB at 1550nm

Fig.S5 Decay curve of Yb/Er ions + Yb/Ho SrTiO3 nanocrystals codoped TZNB at 1550nm

Table S1 Peak-fitting analysis of Raman spectra

Peak position (cm-1)Raman assignments

Blank TZNB NCs-doped TZNB

A. Stretching and bending vibration of Te-O-Te linkages in TeO4

(tbp’s), TeO3+δ polyhedra and TeO3 (tp’s)455 454

B. Vibration of the continuous network comprised of TeO4 tbp’s 608 606

C. Antisymmetrics vibrations of Te-O-Te in TeO3+δ, TeO3 and

TeO4 neworks668 666

D. Stretching vibrations between tellurime and non-bridging

oxygen atoms761 759

E. Continous network vibration of TeO4 tbp’s and a TeO-

stretching vibration of TeO3+δ polyhedra or TeO3798 797