Improved Synthesis of Perovskite CsPbX3@SiO2 (X = Cl, Br, and I) Quantum Dots with Enhanced Stability and Excellent Optical Properties

Wenzhi Wang#

Jinkai Li#, Email

Pengjuan Ni

Bin Liu

Qi Chen

Yizhong LuEmail

Hao WuEmail

Bingqiang Cao

Zongming LiuEmail

School of Materials Science and Engineering, University of Jinan, Jinan, Shandong 250022, China

 

Abstract

Halide perovskite quantum dots (QDs) have been considered to be an outstanding optoelectronic material. However, their poor stability caused by their large specific surface area and high sensitivity to moisture, greatly hinders their practical application. Here, a simple silica (SiO2)-coating process is adopted to solve this problem without affecting their optical properties. Firstly, monodispersed CsPbX3 (X = Cl, Br, I) with cubic morphologies (~8 nm edge lengths) are successfully obtained using a modified hot-injection method, omitting the links of drying and degassing which can reduce energy consumption and save cost. Next, CsPbX3@SiO2 nanoparticles with spherical morphologies (1.2 μm) are obtained through a novel method based on the high hydrolytic rate of tetramethyl orthosilicate (TMOS) using CsPbX3 as the precursor. Photostability tests indicate that the CsPbBr3@SiO2 QDs are markedly more stable than the pure CsPbBr3. The PL intensity of the CsPbBr3@SiO2 dispersed in a mixed solution of toluene and water retained 77% of the initial value even after 12 h, which was much higher than the pure CsPbBr3. Similar experimental results are also observed when CsPbBr3@SiO2 and CsPbBr3 were dispersed in toluene exposed to air. This material provides a novel platform for the application of perovskite quantum dots in light-emitting device applications.

Improved Synthesis of Perovskite CsPbX3@SiO2 (X = Cl, Br, and I) Quantum Dots with Enhanced Stability and Excellent Optical Properties