Template‐Assisted Synthesis of 2D Perovskite Grating Single Crystal Films at Low Temperatures for UV Polarization‐Sensitive Photodetectors

Abstract 2D perovskites have attracted tremendous attention due to their superior optoelectronic properties and potential applications in optoelectronic devices. Especially, the larger bandgap of 2D perovskite means that they are suitable for UV photodetection. However, the layered structure of 2D perovskites hinders the interlayer carrier transport, which limits the improvement of device performance. Therefore, nanoscale structures are normally used to enhance the light absorption ability, which is an effective strategy to improve the photocurrent in 2D perovskite‐based photodetectors. Herein, a template‐assisted low‐temperature method is proposed to fabricate 2D perovskite ((C 6 H 5 C 2 H 4 NH 3 ) 2 PbBr 4 , (PEA) 2 PbBr 4 ) grating single crystal films (GSCFs). The crystallinity of the (PEA) 2 PbBr 4 GSCFs is significantly improved due to the slow evaporation of the precursor solution under low temperatures. Based on this high crystalline quality and extremely ordered microstructures, the metal–semiconductor–metal photodetectors are assembled. Finite‐different time‐domain (FDTD) simulation and experiment indicate that the GSCF‐based photodetectors exhibit significantly improved performance in comparison with the plane devices. The optimized 2D perovskite photodetectors are sensitive to UV light and demonstrate a responsivity and detectivity of 28.6 mA W −1 and 2.4 × 10 11 Jones, respectively. Interestingly, the photocurrent of this photodetector varies as the angle of the incident polarized light, resulting in a high polarization ratio of 1.12.