Perovskite-based time-domain signal-balancing LiDAR sensor with centimeter depth resolution

Abstract

A novel class of semiconducting compounds, metal-halide perovskites (MHPs), has emerged as a versatile platform for advanced optoelectronic device architectures, offering a unique combination of exceptional physical properties and facile processing. In this study, we present a monolithic high-speed photodetector capable of directly sensing the time delay between two light pulses with a temporal resolution of at least 170 ps, corresponding to a light propagation distance of ~5 cm—making it well suited for Light Detection and Ranging (LiDAR) applications. This outstanding time resolution is achieved through a signal-balancing detection scheme that effectively overcomes the limitations of conventional photodetectors, whose response speed is inherently limited by charge-carrier lifetime and transit time. The device exhibits an exceptionally low noise spectral density, comparable to that of state-of-the-art silicon photodiodes. The fully symmetric device stack comprises a crystalline CsPbBr₃ absorber layer tens of microns thick, fabricated via a confined melt process. Comprehensive electro-optical characterization reveals charge-carrier lifetimes and mobilities on both microscopic and macroscopic length scales, using transient photoluminescence, time-resolved photocurrent, time of flight, and terahertz pump–probe spectroscopy. The CsPbBr₃ layer exhibits charge-carrier lifetimes exceeding 100 ns, a microscopic electron–hole mobility of 15 ± 1 cm² V⁻¹ s⁻¹, and a macroscopic non-dispersive hole mobility of 8.5 cm² V⁻¹ s⁻¹.