Solvent-Free Synthesis of Inorganic Rubidium Copper Halides for Efficient Wireless Light Communication and X-Ray Imaging

Lead-free metal halides have recently received sustained attention because of their nontoxicity, low-cost, as well as excellent stability and optoelectronic properties. However, most of the reported lead-free metal halides are synthesized via slow solution-processing at high temperature in toxic solvents, which may impede their commercial applications. Here, a solvent-free strategy is proposed to synthesize inorganic rubidium copper halides (Rb 2 CuX 3 , X = Cl, Br) at room temperature, which exhibit efficient violet emission dominated by a self-trapped excitons (STEs) mechanism and attractive stabilities against ultraviolet illumination and heating. Thus, Rb 2 CuX 3 powders are employed as emitters and scintillators applied in wireless light communication and X-ray imaging technologies. Under orthogonal frequency division multiplexing modulation, emitters demonstrate a broad −3 dB bandwidth of 26.3 MHz and a high received data rate of 205.1 Mbps. Additionally, flexible scintillation films based on as-prepared powders are fabricated and show outstanding X-ray scintillation properties, including a high spatial resolution of 18.1 lp mm −1 and a low detection limit of 104 nGy air s −1 , as well as promising imaging performance for irregular objects. These results suggest large-scale production of nontoxic Rb 2 CuX 3 and their potential commercialization in fields of high-speed light communication and X-ray radiography.