Direct Upcycling of Lead Halide Perovskite Solids by Using Supramolecules for Second Harmonic Generation

Extensive research has been conducted on organic-inorganic lead halide perovskites, exploring their significant potential for applications such as photovoltaics, LEDs, and detectors. However, the major issue of lead toxicity has drawn considerable attention, requiring an urgent solution for the efficient, sustainable upcycling of halide perovskite precursors. In this study, we will introduce a novel family of supramolecular metal halide materials by extracting the primary precursor components of halide perovskites—lead halide and organic amines—into a solid-state crystalline system through the self-assembly of supramolecular structures. Remarkably, we observed nonlinear optical activities in the upcycled single-crystalline self-assembled structures, which can directly produce circularly polarized second harmonic generation (CP-SHG) through linearly polarized infrared light excitation, exhibiting a high polarization efficiency at room temperature. These findings suggest promising applications in the fields of nonlinear optics and photonics. Additionally, annealing the recycled compound at high temperatures convert the supramolecular metal halides back into parent perovskite phase, which demonstrate restored light absorption, and narrow photoluminescence. The supramolecular material’s dual functionality and thermal robustness make it suitable for high-efficiency solar cells, LEDs, and high-temperature sensors, thereby enhancing our understanding of phase transitions in hybrid materials and facilitating the development of advanced multifunctional optical and electronic devices.