Ultraviolet-Visible-Near-Infrared Photoresponses Realized in a Polar Dion-Jacobson Hybrid Perovskite through Light-Induced Pyroelectric Effects

Two-dimensional (2D) polar Dion-Jacobson (DJ) phase hybrid organic-inorganic perovskites (HOIPs) have received increasing interest due to their inherent spontaneous polarization. However, research on utilizing the photoexcited pyroelectric effects to achieve broadband photoresponses in polar DJ hybrid perovskites is still rare. Herein, a new polar DJ hybrid perovskite (1,3-BMACH)PbI4 (1,3-BMACH is 1,3Bis(aminomethyl)cyclohexane) breaks its band gap limitation and shows broadband photoresponses from ultraviolet (266 nm), visible (405-637 nm) to near-infrared region (940 nm) by light induced pyroelectricity. On the basis of spontaneous polarization, a single crystal photodetector based on (1,3-BMACH)PbI4 exhibits a fast rising/falling response time (tau(rise) similar to 12 its, tau(fall) similar to 147 its) and high detectivity of 1.26 x 10(8 )Jones under zero bias at 520 nm. Meanwhile, it also shows a giant contrast of up to 358% for photopyroelectric current to photocurrent signals, which is significantly better than traditional inorganic pyroelectric BaTiO3 film (similar to 110%). Besides, (1,3-BMACH)PbI4 shows an evident reversible thermochromism with color change from orange-yellow to orange-red. The temperature change caused by light on and off leads to a change in spontaneous polarization, which in turn generates photopyroelectric current. The self-driven photodetection based on this mechanism is no longer constrained by the semiconductor properties of the materials, which also broadens the application field of DJ hybrid perovskites and provides beneficial assistance for the development of multifunctional high-performance HOIP pyroelectrics.