A universal hydrochloric acid-assistant powder-to-powder strategy for quick and mass preparation of lead-free perovskite microcrystals.

Lead-free halide perovskite materials possess low toxicity, broadband luminescence and robust stability compared with conventional lead-based perovskites, thus holding great promise for eyes-friendly white light LEDs. However, the traditionally used preparation methods with a long period and limited product yield have curtailed the commercialization of these materials. Here we introduce a universal hydrochloric acid-assistant powder-to-powder strategy which can accomplish the goals of thermal-, pressure-free, eco-friendliness, short time, low cost and high product yield, simultaneously. The obtained Cs 2 Na 0.9 Ag 0.1 In 0.95 Bi 0.05 Cl 6 microcrystals exhibit bright self-trapped excitons emission with quantum yield of (98.3 ± 3.8)%, which could retain (90.5 ± 1.3)% and (96.8 ± 0.8)% after continuous heating or ultraviolet-irradiation for 1000 h, respectively. The phosphor converted-LED exhibited near-unity conversion efficiency from ultraviolet chip to self-trapped excitons emission at ~200 mA. Various ions doping (such as Cs 2 Na 0.9 Ag 0.1 InCl 6 :Ln 3+ ) and other derived lead-free perovskite materials (such as Cs 2 ZrCl 6 and Cs 4 MnBi 2 Cl 12 ) with high luminous performance are all realized by our proposed strategy, which has shown excellent availability towards commercialization.