Efficient and stable emission of warm-white light from lead-free halide double perovskites
Efficient and stable emission of warm-white light from lead-free halide double perovskites
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DOI：
10.1038/s41586-018-0691-0
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发表时间：
2018-11-22
期刊：
影响因子：
64.8
通讯作者：
Tang, Jiang
中科院分区：
文献类型：
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作者：
Luo, Jiajun;Wang, Xiaoming;Tang, Jiang
照明占全球电力消耗的五分之一(1)。具有高效且稳定的白光发射的单一材料是照明应用的理想选择，但使用单一材料很难实现覆盖整个可见光谱的光子发射。金属卤化物钙钛矿具有出色的发射性能(2,3)；然而，这种类型中性能最好的材料含有铅并且稳定性不令人满意。在这里，我们报道了一种无铅双钙钛矿，它通过源自激发态 AgCl6 八面体的 Jahn-Teller 畸变的自陷激子表现出高效稳定的白光发射。通过将钠阳离子合金化到 Cs2AgInCl6 中，我们通过操纵自俘获激子波函数的宇称打破了暗跃迁（反演对称诱导的宇称禁戒跃迁），并降低了半导体的电子维数 (4)。与纯 Cs2AgInCl6 相比，这导致光致发光效率提高了三个数量级。最佳合金化的 Cs-2(Ag0.60Na0.40) InCl6 含有 0.04% 的铋掺杂，可发出暖白光，量子效率为 86 +/- 5%，工作时间超过 1,000 小时。我们预计这些结果将刺激对用于下一代照明和显示技术的基于单发射器的白光发射磷光体和二极管的研究。
Lighting accounts for one-fifth of global electricity consumption(1). Single materials with efficient and stable white-light emission are ideal for lighting applications, but photon emission covering the entire visible spectrum is difficult to achieve using a single material. Metal halide perovskites have outstanding emission properties(2,3); however, the best-performing materials of this type contain lead and have unsatisfactory stability. Here we report a lead-free double perovskite that exhibits efficient and stable white-light emission via self-trapped excitons that originate from the Jahn-Teller distortion of the AgCl6 octahedron in the excited state. By alloying sodium cations into Cs2AgInCl6, we break the dark transition (the inversion-symmetry-induced parity-forbidden transition) by manipulating the parity of the wavefunction of the self-trapped exciton and reduce the electronic dimensionality of the semiconductor(4). This leads to an increase in photoluminescence efficiency by three orders of magnitude compared to pure Cs2AgInCl6. The optimally alloyed Cs-2(Ag0.60Na0.40) InCl6 with 0.04 per cent bismuth doping emits warm-white light with 86 +/- 5 per cent quantum efficiency and works for over 1,000 hours. We anticipate that these results will stimulate research on singleemitter-based white-light-emitting phosphors and diodes for next-generation lighting and display technologies.