Ambardar Sharad, Yang Xiaodong, Gao Jie
Department of Mechanical Engineering, Stony Brook University, Stony Brook, NY11794, USA.
Department of Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, MO, 65409, USA.
Sci Rep. 2024 Nov 6;14(1):26900. doi: 10.1038/s41598-024-78523-y.
As a van der Waals (vdW) layered semiconductor material, lead iodide (PbI) possessing a direct bandgap with strong photoluminescence emission in visible range has gained wide attention in applications of photonic and optoelectronic devices. Here, upconversion photoluminescence (UPL) in exfoliated PbI flakes is demonstrated at room temperature and elevated temperatures. The linear power dependence of UPL emission with 532 nm excitation suggests the one-photon involved multiphonon-assisted UPL emission process, which is revealed by the temperature-dependent UPL emission measurement. Meanwhile, the nonlinear power dependence of UPL emission with 561 nm excitation indicates the transition of UPL emission mechanism from linear to nonlinear regime, and the temperature-dependent UPL emission study further shows that the upconversion is contributed by both the multiphonon-assisted UPL process and the two-photon absorption induced PL process. This study will provide an insight to the understanding of photon upconversion in vdW layered semiconductors and advancing applications in temperature-controlled photon upconversion, tunable photonics, photodetection and imaging.
作为一种范德华（vdW）层状半导体材料，碘化铅（PbI）具有直接带隙且在可见光范围内有强的光致发光发射，在光子和光电器件应用中受到广泛关注。在此，展示了室温及高温下剥离的PbI薄片中的上转换光致发光（UPL）。532 nm激发下UPL发射的线性功率依赖性表明涉及单光子的多声子辅助UPL发射过程，这通过温度相关的UPL发射测量得以揭示。同时，561 nm激发下UPL发射的非线性功率依赖性表明UPL发射机制从线性到非线性区域的转变，并且温度相关的UPL发射研究进一步表明上转换由多声子辅助UPL过程和双光子吸收诱导的PL过程共同贡献。这项研究将为理解vdW层状半导体中的光子上转换以及推进温度控制的光子上转换、可调谐光子学、光电探测和成像方面的应用提供见解。
