High Performance of CsAgBiBr Perovskite-based Photodetectors by Adding DEAC

Perovskite-based photodetectors (PDs) are broadly utilized in optical communication, non-destructive testing, and smart wearable devices due to their ability to convert light into electrical signals. However, toxicity and instability hold back their mass production and commercialization. The lead-free CsAgBiBr double perovskite film, promised to be an alternative, is fabricated by electrophoretic deposition (EPD), which compromises film quality. Herein, we improved the quality of the CsAgBiBr films and the performance of PDs by adding N-acetylethylenediamine (DEAC) to CsAgBiBr perovskite precursor for EPD, in which the ligand DEAC provides a pair of lone electrons to Bi, forming coordinate covalent bonds. The optimized PDs have high detectivity, up to 4.4×10 Jones, and high stability in the air. The high-performance, flexible CsAgBiBr perovskite PDs were fabricated on this basis, it also achieved the detectivity up to 3.2×10 Jones with excellent bending cycle stability. These results propose a feasible approach to improving the crystallization of double perovskite thin films by introducing ligands during the EPD process. Furthermore, they demonstrate enhanced optoelectronic performance, indicating that this method is also applicable to halide perovskites, offering an effective strategy to improve their film quality.