Highly stable CsPbBr3 quantum dots coated with alkyl phosphate for white light-emitting diodes
Tongtong Xuan1, Xianfeng Yang, Sunqi Lou
1Ministry of Education Key Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies, School of Chemistry, School of Materials Science and Engineering, Sun Yat-Sen University, Guangzhou, Guangdong 510275, China. ceswj@mail.sysu.edu.cn.
Abstract:
Inorganic halide perovskite quantum dots (QDs) suffer from problems related to poor water stability and poor thermal stability. Here we developed a simple strategy to synthesize alkyl phosphate (TDPA) coated CsPbBr3 QDs by using 1-tetradecylphosphonic acid both as the ligand for the CsPbBr3 QDs and as the precursor for the formation of alkyl phosphate. These QDs not only retain a high photoluminescence quantum yield (PLQY, 68%) and narrow band emission (FHWM ∼ 22 nm) but also exhibit high stability against water and heat. The relative PL intensity of the QDs was maintained at 75% or 59% after being dispersed in water for 5 h or heated to 375 K (100 °C), respectively. Finally, white light-emitting diodes (WLEDs) with a high luminous efficiency of 63 lm W-1 and a wide color gamut (122% of NTSC) were fabricated by using green-emitting CsPbBr3/TDPA QDs and red-emitting K2SiF6:Mn4+ phosphors as color converters. The luminous efficiency of the WLEDs remained at 90% after working under a relative humidity (RH) of 60% for 15 h, thereby showing promise for use as backlight devices in LCDs.
