Highly efficient copper-based halide single crystals with violet emission for visible light communication

K 2 CuBr 3 single crystals (SCs) are synthesized using a cooling-induced crystallization method with violet emission due to self-trapped excitons (STEs) under photoexcitation. The prepared K 2 CuBr 3 SCs exhibit a high photoluminescence quantum yield (PLQY, 79.2%) and excellent stability against moisture, heat and UV light. When the K 2 CuBr 3 SCs are used as a light source for visible light communication the data transmission rate reaches a striking 248 Mbps, which is more than 33-fold the −3 dB bandwidth. One-dimensional K 2 CuBr 3 single crystals are demonstrated for visible light communication with a high data transmission rate of 248 Mbps, which is more than 33-fold the −3 dB bandwidth.