At present, electric lighting accounts for ~15% of global power consumption and thus the adoption of efficient, low-cost lighting technologies is important. Halide perovskites have been shown to be good emitters of pure red, green and blue light, but an efficient source of broadband white electroluminescence suitable for lighting applications is desirable. Here, we report a white light-emitting diode (LED) strategy based on solution-processed heterophase halide perovskites that, unlike GaN white LEDs, feature only one broadband emissive layer and no phosphor. Our LEDs operate with a peak luminance of 12,200 cd m⁻² at a bias of 6.6 V and a maximum external quantum efficiency of 6.5% at a current density of 8.3 mA cm⁻². Systematic in situ and ex situ characterizations reveal that the mechanism of efficient electroluminescence is charge injection into the α phase of CsPbI₃, α to δ charge transfer and α–δ balanced radiative recombination. Future advances in fabrication technology and mechanistic understanding should lead to further improvements in device efficiency and luminance.

目前，电气照明约占全球功耗的15％，因此采用高效，低成本的照明技术非常重要。卤化物钙钛矿已被证明是纯红色，绿色和蓝色光的良好发射体，但是需要适合照明应用的宽带白色电致发光的有效来源。在这里，我们报告了一种基于固溶处理的异相卤化物钙钛矿的白光发光二极管（LED）策略，与GaN白光LED不同，它仅具有一个宽带发射层，而没有荧光粉。我们的LED在6.6 V偏压下的峰值亮度为12,200 cd m ^-2，在8.3 mA cm ^-2的电流密度下的最大外部量子效率为6.5％。系统的原位和异位表征表明，有效的电致发光机理是电荷注入CsPbI ₃的α相，α到δ的电荷转移以及α–δ平衡的辐射重组。制造技术和机械理解的未来进步将导致器件效率和亮度的进一步提高。