Improved stability and efficiency of perovskite via a simple solid diffusion method

CsPbBr3 perovskite quantum dots (QDs) have excellent properties such as high emission quantum yield, adjustable spectrum, and wide color range. They have potential prospects in light-emitting diode (LED) displays and solar cells. However, CsPbBr3 QDs suffer from a low stability with a high sensitivity to water, heat, and light. Here, for the first time, we report a simple method to improve their stability using a high temperature solid state diffusion to synthesize highly stable and high-quality CsPbBr3 QDs in a small pore size LTA zeolite (0.41 nm). First, the mixture of PbBr2, CsBr and LTA zeolite was heated at 650 degrees C, and the raw materials PbBr2 and CsBr were diffused into the LTA zeolite through a small aperture. Then, the CsBr/ PbBr2 in the composite was reassembled into CsPbBr3 QDs (CsPbBr3@LTA) at room temperature. The CsPbBr3@LTA obtained by this synthesis method have a high photoluminescence quantum yield (PLQY similar to 66%) and extremely high stability. The PLQY of CsPbBr3@LTA remained above 66% after being kept in the air for 17 months. The PL intensity of CsPbBr3@LTA remained 78% of the initial value after being immersed in water for 554 days and the PL intensity changed insignificantly after laser irradiation for 20 days. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

CsPbBr3 perovskite quantum dots exhibit high emission quantum yield and wide color range, but suffer from low stability. A simple method using high temperature solid state diffusion was developed to synthesize highly stable CsPbBr3 QDs in LTA zeolite with a small pore size. The CsPbBr3 QDs obtained showed high photoluminescence quantum yield and remarkable stability.