Terahertz Modulation of Silicon-Based Lead-Free Small-Bandgap Cs2CuSbCl6 Double Perovskite Nanocrystals

In this work, we synthesized a lead-free halide double perovskite, Cs2CuSbCl6, with high carrier mobility via a one-pot hot-injection method. When combined with a high-resistivity silicon wafer, it forms a Type-II heterojunction structure, and its modulation depth reaches 84% by adjusting the annealing temperature. It demonstrates promising modulation performance at 532 nm. Owing to its strong absorption in the ultraviolet region, Cs2CuSbCl6 shows potential for application in ultraviolet-controlled terahertz modulation.