High‐Radiance Near‐Infrared Perovskite Light‐Emitting Diodes with Improved Roll‐Off Degradation

• Published in: Advanced optical materials Vol. 11; no. 4
• Main Authors: Yu, Maotao, Ji, Yongqiang, Yan, Haoming, Hu, Jinhao, Li, Shunde, Xu, Hongyu, Chen, Peng, Zhao, Lichen, Guan, Shuzhen, Bi, Xiaoyin, Yang, Xiaoyu, Jia, Shuang, Yi, Chang, Luo, Deying, Wang, Jianpu, Lu, Zheng‐Hong, Gong, Qihuang, Zhu, Rui
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-02-2023
• Subjects: 4‐phenylenediacetic acid; Additives; Crystal growth; Current injection; Degradation; efficiency roll‐off; high radiance; ion migration; Light emitting diodes; Materials science; Near infrared radiation; Nucleation; Optics; perovskite light‐emitting diodes; Perovskites; Precursors; Quantum efficiency; Radiance; Synergistic effect
• ISSN: 2195-1071; 2195-1071
• DOI: 10.1002/adom.202202043

The external quantum efficiency (EQE) of state‐of‐the‐art near‐infrared perovskite light‐emitting diodes (PeLEDs) is now approaching the limit set by the out‐coupling efficiency. However, there is plenty of room for enhancing these devices’ radiance and the EQE roll‐off. This work reports how conductive and passivating additives construct efficient high‐radiance near‐infrared PeLEDs with improved EQE roll‐off. Specifically, the synergistic effect of 1,4‐phenylenediacetic acid (PDA) and 5‐aminovaleric acid (5‐AVA) is used to regulate the quality of the perovskite emissive layer, thereby enhancing the roll‐off threshold of injection currents (a value at which the device EQE or radiance starts degrading). According to in situ structural evolution analyses from the perovskite precursor to the perovskite crystal, the presence of PDA within the perovskite precursor solution can produce an intermediate phase with 5‐AVA and formanmidinium cation, which can retard the perovskite nucleation and crystal growth, leading to improved perovskite film quality. The resulting champion PeLED delivers among the highest radiance of 505 W sr−1 m−2 and a peak EQE of 17.56%. More importantly, the improved PeLED shows a well‐retained radiance of 80% at a current injection density of up to ≈1800 mA cm−1, opening a new avenue for high‐radiance PeLEDs with improved roll‐off degradation.
This work demonstrates how conductive and passivating additives construct efficient high‐radiance near‐infrared perovskite light‐emitting diodes (PeLEDs) with improved external quantum efficiency roll‐off. 1,4‐phenylenediacetic acid (PDA) and 5‐aminovaleric acid (5‐AVA) retard synergistically the perovskite nucleation and crystal growth, leading to improved perovskite film quality and device current density tolerance, and achieve high‐radiance (505 W sr−1 m−2) near‐infrared PeLEDs with improved roll‐off degradation.