Abstract:
Metal halides, particularly lead-based perovskites, have attracted considerable attention due to their exceptional optoelectronic properties, structural tunability, and ease of processability, making them highly suitable for diverse applications such as photovoltaics, light-emitting diodes (LEDs),and lasers. In this talk, I will first focus on the development of a novel spectrally tunable midinfrared (MIR) detector based on two-dimensional metal halide perovskites (2D-MHPs). I will discuss how the ultralow cross-plane thermal conductivity and pronounced temperature-dependent excitonic resonances of 2D-MHPs make them particularly effective for MIR light detection. Furthermore, I will introduce the infrared-pump visible-probe (IPVP) transient reflection (TR) spectroscopy technique used in our detection approach and explain how we achieved selective detection of specific MIR wavelengths. I will also highlight our membrane structural design and photonic enhancement strategies that enabled a remarkable sensitivity improvement to sub-10 picowatt-per-square-micrometer levels. To address concerns regarding the toxicity of lead, I will present emerging lead-free, environmentally friendly metal halides as viable alternatives. These include all-inorganic and hybrid copper-based halides as well as antimony-based hybrid halides. I will discuss their synthesis, structural design, and optical properties, demonstrating how their emission characteristics can be tuned through compositional adjustments. Finally, I will explore their promising applications in lighting and display technologies.