近日，中国科学技术大学肖正国教授领导的研究小组与美国北卡罗莱纳大学教堂山分校的黄劲松教授合作，成功研制出了高亮度和稳定的单晶钙钛矿发光二极管。相关成果于2023年2月27日在国际权威学术期刊《自然—光子学》上发表。
该研究团队证实了短器件寿命和低亮度这两个问题可以通过原位溶液生长的钙钛矿单晶(SCs)来缓解。通过使用混合阳离子，在前体中添加过量的卤化铵和聚维酮，使陷阱密度最小化，SCs的外部光致发光量子产额（PLQY）提高至28.3％，对应于内部PLQY为89.4％。得益于SCs中俄歇复合的抑制，厚度为1.5μm的SC-PeLEDs表现出86,000cdm-2的高亮度和11.2%的峰值外量子效率。由于离子迁移得到抑制，SC-PeLEDs的外推T50寿命在初始亮度为100cdm-2时达到12,500h。该研究结果表明，SC生长代表了一种可行的途径，可以增加PeLEDs的寿命，用于实际应用。
据了解，金属卤化物钙钛矿发光二极管(PeLEDs)因其可调谐的发射波长、窄的发射带宽和高外部量子效率而备受关注。然而，PeLEDs面临两个关键问题，限制了它们的潜在应用，即离子迁移导致的短器件寿命和严重俄歇复合导致的低亮度。
附：英文原文
Title: Highly bright and stable single-crystal perovskite light-emitting diodes
Author: Chen, Wenjing, Huang, Zongming, Yao, Haitao, Liu, Yan, Zhang, Yihan, Li, Zhijian, Zhou, Hongmin, Xiao, Peng, Chen, Tao, Sun, Haiding, Huang, Jinsong, Xiao, Zhengguo
Issue&Volume: 2023-02-27
Abstract: Metal-halide perovskite light-emitting diodes (PeLEDs) have attracted great interest because of their tunable emission wavelength, narrow emission bandwidth and high external quantum efficiency. However, PeLEDs face two critical issues that limit their potential applications: short device lifetime due to ion migration and low brightness due to severe Auger recombination. Here we demonstrate that both issues can be mitigated by in situ solution-grown perovskite single crystals (SCs). By minimizing the trap density using mixed cations and adding excess ammonium halides and polyvidone to the precursor, the external photoluminescence quantum yield (PLQY) of the SCs is enhanced to 28.3%, corresponding to an internal PLQY of 89.4%. Benefitting from the suppressed Auger recombination in SCs, SC-PeLEDs with a thickness of 1.5μm exhibit a high luminance of 86,000cdm-2 and a peak external quantum efficiency of 11.2%. Thanks to suppressed ion migration, the extrapolated T50 lifetime for SC-PeLEDs reaches a value of 12,500h at an initial luminance of 100cdm-2. Our results show that SC growth represents a viable route to increase the lifetime of PeLEDs for practical applications.
DOI: 10.1038/s41566-023-01167-3
Source: https://www.nature.com/articles/s41566-023-01167-3