Unprecedented Self-Powered Visible-Infrared Dual-Modal Photodetection Induced by a Bulk Photovoltaic Effect in a Polar Perovskite.

Visible-infrared dual-modal light harvesting is crucial for various optoelectronic devices, particularly for solar cells and photodetectors. Hybrid metal-halide perovskites are recently emerging for visible-infrared dual-modal photodetection owing to their prominent multiphoton absorption and carrier transport performances. However, they work relying on an applied external power source or complicated heterostructures. It is still a difficult task to realize visible-infrared dual-modal self-powered photoresponse induced by a bulk photovoltaic effect (BPVE) in a single material. In this work, we constructed a polar multilayered perovskite, (Br-BA) 2 (EA) 2 Pb 3 Br 10 (BEP; EA + = ethylammonium, and Br-BA + = 4-brombutylammonium). Notably, the polar feature endows BEP with a BPVE. In addition, BEP presents a distinctive two-photon activity arising from the layered quantum-well structure. Benefitting from these striking characteristics, self-powered visible-infrared dual-modal photodetection is realized, and a direct self-powered detection of 800 nm light with a photocurrent of 2.1 nA cm -2 is achieved. This work will inspire the design of desired photoelectric materials with a BPVE for high-performance self-powered visible-infrared dual-modal photodetection.