Ultrastable Photodetectors Based on Blue CsPbBr<sub>3</sub> Perovskite Nanoplatelets via a Surface Engineering Strategy
Hao Wang, Zhentao Du, Xue Jiang, Sheng Cao, Bingsuo Zou, Jinju Zheng, Jialong Zhao
Abstract
Recently, photodetectors based on perovskite nanoplatelets (NPLs) have attracted considerable attention in the visible spectral region owing to their large absorption cross-section, high exciton binding energy, excellent charge transfer properties, and appropriate flexibility. However, their stability and performance are still challenging for perovskite NPL photodetectors. Here, a surface engineering strategy to enhance the optical stability of blue-light CsPbBr 3 NPLs by acetylenedicarboxylic acid (ATDA) treatment has been developed. ATDA has strong binding capacity and a short chain length, which can effectively passivate defects and significantly improve the photoluminescence quantum efficiency, stability, and carrier mobility of NPLs. As a result, ATDA-treated CsPbBr 3 NPLs exhibit improved optical properties in both solutions and films. The NPL solution maintains high PL performance even after being heated at 80 °C for 2 h, and the NPL film remains nondegradable after 4 h of exposure to ultraviolet irradiation. Especially, photodetectors based on the treated CsPbBr 3 NPL films demonstrate exceptional performance, especially when the detectivity approaches up to 9.36 × 10 12 Jones, which can be comparable to the best CsPbBr 3 NPL photodetectors ever reported. More importantly, the assembled devices demonstrated high stability (stored in an air environment for more than 30 days), significantly exceeding that of untreated NPLs.