UV and NIR Dual-Band Photodetector Enabled by p-Type Perovskite and Semitransparent Microcavity

Abstract

Narrowband photodetectors (NPDs) are essential for surveillance, photometry, and remote sensing. However, few studies have demonstrated multiple narrowband detection abilities within a single PD, particularly in the ultraviolet (UV) and near-infrared (NIR) regions, which are not directly recognized by the human eyes. In this work, we present a method for UV and NIR dual-band photodetection on the same device through integrating tandem-like perovskite/organic bulk-heterojunction (P-OBHJ) with a translucent microcavity. By leveraging the self-doping effect of perovskites, we fabricated p-type MAPbI₃ films with the unbalanced electron–hole transport, enabling complete visible-light depletion upon bottom illumination. Meanwhile, NIR light passes through the entire perovskite layer to reach the OBHJ layers, ultimately resulting in a narrowband response to NIR light. Upon top illumination, the semitransparent microcavity selectively transmits only UV light, achieving narrowband UV detection. As a result, the optimized device exhibits the responsivity of 0.21 and 0.03 A/W with the corresponding shot-noise-limited specific detectivity reaching 4 × 10¹² and 6 × 10¹¹ Jones, at the peak wavelengths of 810 and 330 nm, respectively. Last, we showcase prototype applications of the dual-band PDs as heartbeat and solar UV intensity monitors, providing a novel strategy for the development of multifunctional NPD.