Bilayered Dion–Jacobson Hybrid Perovskite Bulk Single Crystals Constructed with Aromatic Diammonium for Ultraviolet–Visible–Near-Infrared Photodetection

Two-dimensional
(2D) Dion–Jacobson (DJ) hybrid perovskites
(HPs) are widely used in the photodetection field due to their high
stability and excellent carrier transport performance. However, current
photodetectors based on DJ HPs can work only in the ultraviolet and
visible wavebands, which limits their application in near-infrared
(NIR) photodetection. Herein, for the first time, ultraviolet–visible–NIR
photodetection is realized in the bulk single crystal of 2D bilayered
DJ HP (3AMPY)­(EA)­Pb2Br7 (3AMPY = 3-(aminomethyl)­pyridinium,
EA = ethylamine). Structurally, the introduction of aromatic diammonium
makes (3AMPY)­(EA)­Pb2Br7 have a shorter layer
spacing (3.561 Å) and a more rigid structure. In addition, benefiting
from the strong quantum and dielectric confinements of 2D HPs, (3AMPY)­(EA)­Pb2Br7 shows an excellent two-photon absorption (TPA)
coefficient of up to 61.1 cm/MW under the excitation of an 800 nm
femtosecond laser. Notably, (3AMPY)­(EA)­Pb2Br7 exhibits efficient photodetection from ultraviolet (377 nm) and
visible (405 nm) to NIR (800 nm) wavebands, with on/off ratios of
current higher than 103.