Liu Junhao, Shi Xiaorong, Li Yajing, Cui Yuanhao, Meng Na, Xu Yutian, Wang Ziqiang, Ke Xinwu, Lu Mengmeng, Min Xue, Hu Zhelu, Chao Lingfeng, Xia Yingdong, Xu Kui, Guo Qingxun, Chen Yonghua
State Key Laboratory of Flexible Electronics (LoFE) & Institute of Advanced Materials (IAM), School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), Nanjing 211816, Jiangsu, China.
J Phys Chem Lett. 2025 Sep 11;16(36):9500-9506. doi: 10.1021/acs.jpclett.5c02361. Epub 2025 Sep 3.
Thermally evaporated perovskite light-emitting diodes (PeLEDs) hold great promise for high-quality display applications due to their exceptional large-area uniformity and ease of pixelation and integration. Beyond efficiency considerations, display technologies demanded exceptionally high luminance performance from LEDs. While the brightness of blue and green PeLEDs had progressed rapidly, the performance of red PeLEDs lagged significantly. In this work, we achieved a breakthrough in bright thermally evaporated red PeLEDs through in situ defect passivation by coevaporating a molecular additive, 2,8-bis(diphenylphosphoryl)dibenzofuran (PPF), with PbI and CsBr. First-principles calculations revealed that PPF stabilized the outer electrons of the Pb atoms, effectively compensating for surface halide (I/Br) vacancies in CsPbIBr crystals. Experimental studies confirmed that PPF not only passivated defects but also enhanced film crystallinity and uniformity, leading to improved luminescence efficiency. When incorporated into PeLEDs, PPF enabled devices to achieve a record luminance of 3789 cd m for thermally evaporated red PeLEDs, along with stable deep-red emission at 650 nm, matching the Rec. 2020 standard for red emission.
热蒸发钙钛矿发光二极管（PeLEDs）因其出色的大面积均匀性以及易于像素化和集成的特性，在高质量显示应用方面具有巨大潜力。除了效率方面的考虑，显示技术还要求LED具备极高的亮度性能。尽管蓝色和绿色PeLEDs的亮度已取得快速进展，但红色PeLEDs的性能仍显著滞后。在这项工作中，我们通过与PbI和CsBr共蒸发一种分子添加剂2,8-双（二苯基磷酰基）二苯并呋喃（PPF）进行原位缺陷钝化，在明亮的热蒸发红色PeLEDs方面取得了突破。第一性原理计算表明，PPF稳定了Pb原子的外层电子，有效补偿了CsPbIBr晶体中的表面卤化物（I/Br）空位。实验研究证实，PPF不仅钝化了缺陷，还提高了薄膜的结晶度和均匀性，从而提高了发光效率。当将PPF引入PeLEDs时，器件实现了热蒸发红色PeLEDs创纪录的3789 cd m亮度，以及在650 nm处稳定的深红色发射，符合Rec. 2020红色发射标准。
