Metal halide perovskites have emerged as exceptional semiconductors for optoelectronic applications. Substitution of the monovalent cations has advanced luminescence yields and device efficiencies. Here, we control the cation alloying to enhance optoelectronic performance through alteration of the charge carrier dynamics in mixed-halide perovskites. In contrast to single-halide perovskites, we find high luminescence yields for photoexcited carrier densities far below solar illumination conditions. Using time-resolved spectroscopy we show that the charge carrier recombination regime changes from second to first order within the first tens of nanoseconds after excitation. Supported by microscale mapping of the optical bandgap, electrically gated transport measurements and first-principles calculations, we demonstrate that spatially varying energetic disorder in the electronic states causes local charge accumulation, creating p- and n-type photodoped regions, which unearths a strategy for efficient light emission at low charge-injection in solar cells and light-emitting diodes.

金属卤化物钙钛矿已经成为光电子应用中的特殊半导体。单价阳离子的取代具有提高的发光产量和器件效率。在这里，我们控制阳离子合金化，以通过改变混合卤化物钙钛矿中的电荷载流子动力学来增强光电性能。与单卤化物钙钛矿相反，我们发现光激发载流子密度的发光产量高，远低于太阳光照条件。使用时间分辨光谱，我们显示了在激发后的几十纳秒内，电荷载流子的复合形式从二阶变为一阶。通过光学带隙的微尺度映射，电门传输测量和第一性原理计算，