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 1,3-Bis(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 (τrise ∼ 12 μs, τfall ∼ 147 μs) and high detectivity of 1.26 × 108 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 (∼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.