Imprinted 2D/3D Perovskite Film with Gradient Phase Distribution Toward High-Performance Polarization-Sensitive Photodetector

Polarization-sensitive perovskite photodetectors (PSPPDs) are attracting wide attention due to their potential application in remote sensing, optical radar, astronomy detection, and military. The current mainstream of PSPPDs is forming perovskites into anisotropy structures, especially nanowires (NWs). However, synthesizing high-quality perovskite NWs can be a challenging process. Two-dimensional (2D) Ruddlesden–Popper perovskites with the multilayered structure have emerged as promising candidates in optoelectronic devices for their higher oxygen and moist resistance than their three-dimensional (3D) counterparts. Previous research suggested that the spontaneously formed multiple phases of 2D perovskite films are always inhomogeneously distributed, hindering radiative recombination. It is an effective method to modulate perovskite phase distribution to facilitate the separation of charge carriers and improve carrier lifetime. This work reports a PSPPD with high optoelectronic performance based on a 2D/3D perovskite heterojunction with a facile preparation process. The vertical gradient phase distribution of synthesized (PEA)₂(MA)_n-1Pb_nI_3n+1 film was determined by transient absorption (TA). This ordered phase distribution causes a progressive band energy alignment, which promotes the separation of photogenerated carriers, thereby enhancing the photodetector responsivity. Furthermore, the imprinting method was adopted to form NW-like nanoscale linear patterns on the film surface, realizing polarized light detection. The responsivity of the PSPPD reaches almost 90 A/W, and the detectivity reaches the order of 10¹²Jones. The photoluminescence intensity of the perovskite film with nanoscale linear patterns presents an anisotropy ratio of 2.2, and the photocurrent of the PSPPD exhibits an anisotropy ratio of 1.6.