Improved Stability and Efficiency of Perovskite Via a Simple Solid Diffusion Method

Abstract 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 (0.41nm). First, the mixture of PbBr2, CsBr and LTA zeolite was heated at 650 0C, 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 ∼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.