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)2Pb3Br10 (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.