Wavelength selective and cesium halides additive photodetectors based on two-dimensional perovskite: (C8H9NH3)2PbBr4

Considering of cost-effective and simple assembly principle of organic-inorganic halide perovskite (OIHP), producing perovskites into polycrystalline thin films from precursor solution has proved to be appealing. In this paper, (C8H9NH3)2PbBr4 was fabricated based on C8H9NH3Br (PEABr) and PbBr2 according to compositions in the vicinity of (PEA)2PbI4, and the two-dimensionally (2D) perovskite was obtained which entitled with superior photoelectric performance, excellent solution processability and flexible substrates compatibility. And hydrophobic nature of spacer cation of aromatic alkylammonium or a large aliphatic both with the highly consistent orientation of 2D perovskites are beneficial for reducing the grain boundaries density. Meanwhile, optimized (PEA)2PbBr4 were obtained via CsBr additive. Systematic material characterizations manifested enhanced surface morphology, photoluminescence efficiency and carrier lifetime of the CsBr modified (PEA)2PbBr4. Then related (PEA)2PbBr4 based photodetectors exhibited a good responsivity of 0.67 AW−1 when detectivity approached 5.2×1011 Jones, and a large on/off ratio about 500 was obtained. Meanwhile, the devices possessed noticeable stability during the optical switch tests with the rise time and decay time about 0.28 s and 0.21 s for CsBr dopped devices illuminated by 385 nm under 10 V bias. More importantly, spectral wavelength selectivity of CsBr based photodetector indicated the potential utilization in ultraviolet detecting when a wide bandgap of 3.018 eV was obtained.