High-speed, self-powered 2D-perovskite photodetectors with exceptional ambient stability enabled by planar nanocavity engineering

Advancements in photodetector (PD) technology are pivotal for the evolution of optical communication and imaging systems. Addressing the demands of these applications necessitates PDs that can deliver both high-speed response and high sensitivity. In this context, we introduce an innovative high-speed PD design utilizing ultrathin two-dimensional metal halide perovskites (2D-MHP), coupled with a planar nanocavity to significantly enhance optical absorptance—achieving more than a fourfold increase in a solution-processed 10-nm-thick 2D-MHP film. This integration facilitates an exceptional response time (30 ns) alongside a high responsivity of 2.12 A W⁻¹. Our method overcomes traditional constraints related to thickness and absorption, thereby optimizing device speed and dark noise features through active area variation. Intriguingly, the nanocavity architecture provided a unique protection of 2D-MHP layers, realizing remarkable operational and environmental stability: our devices maintain performance integrity for over 150 days. Notably, our best-performing cavity-enhanced devices exhibit the capability to establish an optical wireless communication link, achieving a data transmission rate of 20 Mbps. This approach effectively tackles the challenges posed by the low absorption of ultrathin layers, heralding a new era for applications in imaging, optical communication systems, and more.