All-Optical Mid-Infrared Photodetectors Based on Two-Dimensional Metal Halide Perovskites

Two-dimensional (2D) metal halide perovskites (MHPs) have gained significant research interest due to their excellent stability and tunable optoelectronics properties compared with their three-dimensional (3D) counterparts. A major challenge with 2D-MHP is their ultralow thermal conductivity, which is generally considered a drawback for optoelectronic applications. In our work, we transform this limitation into an advantage by utilizing the low thermal conductivity along with their temperature-sensitive excitonic resonances to develop thermal-based, spectrally tunable mid-infrared (MIR) photodetectors. Our approach leverages the thermal response of 2D-MHPs to create a photodetector capable of operating at room temperature, eliminating the need for the complex cooling systems typically required by traditional infrared detectors. To enhance the sensitivity of the device, we employ dielectric membrane-based structures, enabling detection limits as low as 10 pW●µm^-2. Our work introduces a new application for 2D-MHPs in the field of infrared detection, offering a scalable, cost-effective solution that could pave the way for the development of next-generation optoelectronic devices.