Self-Powered Broadband Photodetection in Hybrid Perovskite Enabled by Photovoltaic Effect.

A pressing challenge in environmental, biomedical, and infrared sensing is the creation of versatile detectors capable of operating across wide wavelengths. Due to the fundamental limitations imposed by intrinsic bandgap structures, the operational scope of most existing photoactive materials remains predominantly confined to the ultraviolet and visible regions, thereby impeding the development of effective broadband detection systems. In this study, we have designed a lead-free polar perovskite [2-(4-aminobutyl)guanidine]BiBr5 (1). Importantly, the built-in electric field associated with the intrinsic symmetry breaking in 1 induces bulk photovoltaic effect under illumination. Furthermore, 1 exhibits a distinctive photopyroelectric (PPE) effect, which broadens the detection wavelength and breaks the limitation of the optical absorption bandgap, covering the range of the 266-980 nm spectral region and exceeding the optical absorption bandgap.