Br-I ordered CsPbBr2I perovskite single crystal toward extremely high mobility

Cesium-based inorganic hybrid halide lead perovskite CsPbX3 (X = I, Br, Cl) have emerged as a kind of photovoltaic material with immense potential. However, there is still a challenge for the growth of Br-I hybrid CsPbBr3−XIX single crystals (SCs) to further investigate of CsPbX3 perovskites. Herein, we present a new method that realizes growth of halogen-ordered CsPbBr2I SCs by introducing an unprecedented Br-I ordered intermediate, i.e., PbBrI-(DMSO)2. With separately arranged Br− and I− in the CsPbBr2I lattice, the important role of I− in the charge transport is revealed in that separated I− layers construct the required lower energy transport channel. Benefiting from this, the as-grown ordered CsPbBr2I SCs are experimentally proven to have an ultra-high carrier mobility of 2,574 cm2·V−1·s−1, as well as remarkable anisotropy. Br-I order regulation is shown to be feasible, which innovatively offers a new strategy and guidance to promote the performance of CsPbX3 perovskites.