Ionic Liquid Assisted Microwave Synthesis of Cu-In-Zn-S/ZnS Quantum Dots and Their Application in White LED

doi:10.15541/jim20190260

Abstract

Abstract:

Cu-In-Zn-S (CIZS) quantum dots (QDs) are considered as promising fluorescent materials owing to their low toxicity, wide emission range and large Stokes shifts, which have a wide prospect in lighting field. CIZS QDs were prepared via ionic liquid assisted microwave method in aqueous solution. The effects of reaction time, addition amount of ligand and pH of precursor solution on phase composition, microscopic morphology and photoluminescence (PL) property were investigated. Results showed that the reaction rate could be accelerated with the assistance of ionic liquid, i.e. the reaction time reducing from 180 min to 30 min. The size of QDs gradually increased with the increase of reaction time, resulting in red shift of emission peak from 609.2 to 634.6 nm. Moreover, the particle size of CIZS QDs increased with the increase of n_GSH/n_(CuInZn)ratios, resulting in the red shift of emission peak from 622.6 nm to 631.6 nm. Meanwhile, the PL intensity of QDs increased and reached the maximum at n_GSH/n_(CuInZn)=15. Furthermore, the surface defect state was effectively passivated with the increase of pH of precursor solution due to enhanced bonding force between deprotonized groups (-SH, -NH₂) and QDs, resulting in enhancement of PL intensity. And the optimal pH was 8.5. The average hydrodynamic size of CIZS QDs increased from 99 nm to 241 nm with the increase of pH, and the relative Zeta potential ranged from -27.7 mV to -41.1 mV, indicating the excellent stability of CIZS QDs solution. Emission intensity of QDs could be enhanced significantly after coating with ZnS shells. White LED device was fabricated by combining CIZS QDs and a blue chip, the color rendering index and luminous efficiency of device were 85.6 and 34.8 lm/W, respectively, which provided a reference for the application of water soluble multiple QDs in white LEDs.

Key words: ionic liquid, microwave, aqueous phase synthesis, Cu-In-Zn-S, quantum dots

CLC Number:

O611

CHEN Ting, XU Yanqiao, JIANG Weihui, XIE Zhixiang, WANG Lianjun, JIANG Wan. Ionic Liquid Assisted Microwave Synthesis of Cu-In-Zn-S/ZnS Quantum Dots and Their Application in White LED[J]. Journal of Inorganic Materials, 2020, 35(4): 439-446.

Figures/Tables 11

Fig. 1 XRD patterns of CIZS QDs prepared with different reaction time (with adding ionic liquid, nGSH/n(CuInZn)=15, pH=8.5)

Fig. 2 (a) PL spectra and (b) evolution of the emission intensity and peak position of CIZS QDs prepared with different reaction time (without ionic liquid, nGSH/n(CuInZn)=15, pH=8.5)

Fig. 3 (a) PL spectra and (b) evolution of the emission intensity and peak position of CIZS QDs prepared with different reaction time (with ionic liquid, nGSH/n(CuInZn)=15, pH=8.5)

Fig. 4 TEM images of CIZS QDs prepared with ionic liquid for different reaction time (nGSH/n(CuInZn)=15, pH=8.5) (a) 10 min; (b) 20 min; (c) 30 min

Fig. 5 XRD patterns of CIZS QDs prepared with different nGSH/n(CuInZn) ratios (with ionic liquid for 30 min, pH=8.5)

Fig. 6 (a) PL spectra and (b) evolution of the emission intensity and peak position of CIZS QDs with different nGSH/n(CuInZn) ratios (with ionic liquid for 30 min, pH=8.5)

Fig. 7 TEM images of CIZS QDs prepared with nGSH/n(CuInZn) ratios (with ionic liquid for 30 min, pH=8.5) at (a) 5, (b) 15, and (c) 25

Fig. 8 (a) PL spectra and (b) evolution of the emission intensity and peak position of CIZS QDs prepared with different pH (with ionic liquid for 30 min, nGSH/n(CuInZn)=15)

Fig. 9 Zeta potential and average hydrodynamic size of CIZS QDs with different pH (with ionic liquid for 30 min, nGSH/n(CuInZn)=15)

Fig. 10 PL spectra of CIZS and CIZS/ZnS QDs

Fig. 11 (a) EL spectra and (b) CIE coordinate of white LED

References 38

[1]	YE S, XIAO F, PAN Y X , et al. Phosphors in phosphor-converted white light-emitting diodes: recent advances in materials, techniques and properties. Mater. Sci. Eng. R, 2010,71(1):1-34.
[2]	HOERDER G J, SEIBALD M, BAUMANN D , et al. Sr[Li₂Al₂O₂N₂]:Eu²⁺- a high performance red phosphor to brighten the future. Nat. Commun., 2019,10:1824.
[3]	WANG L, XIE R J, SUEHIRO T , et al. Down-conversion nitride materials for solid state lighting: recent advances and perspectives. Chem. Rev., 2018,118(4):1951-2009.
[4]	PIETRYGA J M, PARK Y S, LIM J , et al. Spectroscopic and device aspects of nanocrystal quantum dots. Chem. Rev., 2016,116(18):10513-10622.
[5]	DAICHO H, IWASAKI T, ENOMOTO K , et al. A novel phosphor for glareless white light-emitting diodes. Nat. Commun., 2012,3:1132.
[6]	GUPTA K V K, MULEY A, YADAV P , et al. Combustion synthesis of YAG:Ce and related phosphors. Appl. Phys. B, 2011,105(2):479-484.
[7]	KANG X, YANG Y, WANG L , et al. Warm white light emitting diodes with gelatin-coated AgInS₂/ZnS core/shell quantum dots. ACS Appl. Mater. Interfaces, 2015,7(50):27713-27719.
[8]	CHUANG P H, LIN C C, LIU R S . Emission-tunable CuInS₂/ZnS quantum dots: structure, optical properties, and application in white light-emitting diodes with high color rendering index. ACS Appl. Mater. Interfaces, 2014,6(17):15379-15387.
[9]	ILAIYARAJA P, MOCHERLA P S V, SRINIVASAN T K , et al. Synthesis of Cu-deficient and Zn-graded Cu-In-Zn-S quantum dots and hybrid inorganic-organic nanophosphor composite for white light emission. ACS Appl. Mater. Interfaces, 2016,8(19):12456-12465.
[10]	JO D Y, YANG H . Spectral broadening of Cu-In-Zn-S quantum dot color converters for high color rendering white lighting device. J. Lumin., 2015,166:227-232.
[11]	GUGULA K, STEGEMANN L, CYWINSKI P J , et al. Facile surface engineering of CuInS₂/ZnS quantum dots for LED down- converters. RSC Adv., 2016,6(12):10086-10093.
[12]	CHEN J, LI Y, WANG L , et al. Achieving deep-red-to-near- infrared emissions in Sn-doped Cu-In-S/ZnS quantum dots for red-enhanced white LEDs and near-infrared LEDs. Nanoscale, 2018,10(20):9788-9795.
[13]	CHEN F, YAO Y, LIN H , et al. Synthesis of CuInZnS quantum dots for cell labelling applications. Ceram. Int., 2018,44(Suppl.1):S34-S37.
[14]	CHEN B, ZHONG H, WANG M , et al. Integration of CuInS₂- based nanocrystals for high efficiency and high colour rendering white light-emitting diodes. Nanoscale, 2013,5(8):3514-3519.
[15]	XIE R, RUTHERFORD M, PENG X . Formation of high-quality I-III-VI semiconductor nanocrystals by tuning relative reactivity of cationic precursors. J. Am. Chem. Soc., 2009,131(15):5691-5697.
[16]	ZHANG W, LOU Q, JI W , et al. Color-tunable highly bright photoluminescence of cadmium-free Cu-doped Zn-In-S nanocrystals and electroluminescence. Chem. Mater., 2014,26(2):1204-1212.
[17]	KIM J H, YANG H . High-efficiency Cu-In-S quantum-dot- light-emitting device exceeding 7%. Chem. Mater., 2016,28(17):6329-6335.
[18]	WU R, WANG T, WU M , et al. Synthesis of highly stable CuInZnS/ ZnS//ZnS quantum dots with thick shell and its application to quantitative immunoassay. Chem. Eng. J., 2018,348:447-454.
[19]	CHEN X, CHEN S, XIA T , et al. Aqueous synthesis of high quality multicolor Cu-Zn-In-S quantum dots. J. Lumin., 2017,188:162-167.
[20]	LIU Y, CHEN X, MA Q . An efficient microwave-assisted hydrothermal synthesis of high-quality CuInZnS/ZnS quantum dots. New J. Chem., 2018,42(6):4102-4108.
[21]	JIANG T, SONG J, WANG H , et al. Aqueous synthesis of color tunable Cu doped Zn-In-S/ZnS nanoparticles in the whole visible region for cellular imaging. J. Mater. Chem. B, 2015,3(11):2402-2410.
[22]	XU Y, CHEN T, HU X , et al. The off-stoichiometry effect on the optical properties of water-soluble copper indium zinc sulfide quantum dots. J. Colloid Interf. Sci., 2017,496:479-486.
[23]	陈婷, 徐彦乔, 王连军 . 一种离子液体辅助微波法合成I-III-VI族多元量子点的制备方法及其制得的产品. 中国, CN201610920307. 2. 2018.08.03.
[24]	ZHANG J, XIE R, YANG W . A simple route for highly luminescent quaternary Cu-Zn-In-S nanocrystal emitters. Chem. Mater., 2011,23(14):3357-3361.
[25]	CHENG J, LI D, CHENG T , et al. Aqueous synthesis of high- fluorescence CdZnTe alloyed quantum dots. J. Alloys. Compd., 2014,589:539-544.
[26]	ZHANG J, SUN W, YIN L , et al. One-pot synthesis of hydrophilic CuInS₂ and CuInS₂-ZnS colloidal quantum dots. J. Mater. Chem. C, 2014,2(24):4812-4817.
[27]	YU Y, XU L, CHEN J , et al. Hydrothermal synthesis of GSH- TGA co-capped CdTe quantum dots and their application in labeling colorectal cancer cells. Colloid. Surface B, 2012,95:247-253.
[28]	CHEN Y, LI W, WANG J , et al. Microwave-assisted ionic liquid synthesis of Ti³⁺ self-doped TiO₂ hollow nanocrystals with enhanced visible-light photoactivity. Appl. Catal. B, 2016,191:94-105.
[29]	ZHU Y J, CHEN F . Microwave-assisted preparation of inorganic nanostructures in liquid phase. Chem. Rev., 2014,114(12):6462-6555.
[30]	VEMPATI S, ERTAS Y, UYAR T . Sensitive surface states and their passivation mechanism in CdS quantum dots. J. Phys. Chem. C, 2013,117(41):21609-21618.
[31]	LENG Z, HUANG L, SHAO F , et al. Facile synthesis of Cu-In-Zn-S alloyed nanocrystals with temperature-dependent photoluminescence spectra. Mater. Lett., 2014,119:100-103.
[32]	DING Y, SHEN S Z, SUN H , et al. Synthesis of L-glutathione- capped-ZnSe quantum dots for the sensitive and selective determination of copper ion in aqueous. Sensor. Actuat. B, 2014,203:35-43.
[33]	WANG Y, LIANG X, MA X , et al. Simple and greener synthesis of highly photoluminescence Mn²⁺-doped ZnS quantum dots and its surface passivation mechanism. Appl. Surf. Sci., 2014,316:54-61.
[34]	LUO Z, ZHANG H, HUANG J , et al. One-step synthesis of water- soluble AgInS₂ and ZnS-AgInS₂ composite nanocrystals and their photocatalytic activities. J. Colloid Interf. Sci., 2012,377(1):27-33.
[35]	ZHANG J, LI J, ZHANG J , et al. Aqueous synthesis of ZnSe nanocrystals by using glutathione as ligand: the pH-mediated coordination of Zn²⁺ with glutathione. J. Phys. Chem. C, 2010,114(25):11087-11091.
[36]	REGULACIO M D, WIN K Y, LO S L , et al. Aqueous synthesis of highly luminescent AgInS₂-ZnS quantum dots and their biological applications. Nanoscale, 2013,5(6):2322-2327.
[37]	KO M, YOON H C, YOO H , et al. Highly efficient green Zn-Ag- In-S/Zn-In-S/ZnS QDs by a strong exothermic reaction for down- converted green and tripackage white LEDs. Adv. Funct. Mater., 2017,27(4):1602638.
[38]	LIU Z, TANG A, WANG M , et al. Heating-up synthesis of cadimum-free and color-tunable quaternary and five-component Cu-In-Zn-S-based semiconductor nanocrystals. J. Mater. Chem. C, 2015,3(39):10114-10120.