Achieving Light‐Induced Ultrahigh Pyroelectric Charge Density Toward Self‐Powered UV Light Detection

Abstract From the ferroelectric material family, BaTiO 3 (BTO) demonstrates quite excellent pyroelectric features due to its inherent intrinsic spontaneous polarization capability. The pyroelectric effect induced by ultraviolet (UV) illumination can be utilized to realize the self‐powered detection of the UV light, where the photosensing characteristics can be determined by the change in charge density with time. Here, a method to increase the charge density by removing the underneath substrate and reducing the device thickness is reported. A floating BTO‐based device with thickness of ≈0.35 mm demonstrates an ultrahigh charge density of ≈1787.2 nC cm −2 under 365 nm light illumination, which is almost 11.4 times higher than that of a 0.85 mm thick BTO device on Al 2 O 3 substrate. These reported findings establish a new strategy for enhancing the charge density of the BTO‐based devices with improved responses, which will be very helpful in upgrading the performances of future technological devices in optoelectronic devices and energy harvesters.