Bright and Stable Red Perovskite LEDs under High Current Densities
Zhixiang Ren, Bingbing Guo, Shengnan Liu, Yaxiao Lian, Yaxin Wang, Shiyu Xing, Yichen Yang, Gan Zhang, Weidong Tang, Yuxiang Gao, Zixiang Wang, Jiawei Hong, Minhui Yu, Shiyuan Zhang, Dongchen Lan, Chen Zou, Baodan Zhao, Dawei Di
Abstract
Perovskite LEDs (PeLEDs) have emerged as a next-generation light-emitting technology. Recent breakthroughs were made in achieving highly stable near-infrared and green PeLEDs. However, the operational lifetimes ( T 50 ) of visible PeLEDs under high current densities (>10 mA cm –2 ) remain unsatisfactory (normally <100 h), limiting the possibilities in solid-state lighting and AR/VR applications. This problem becomes more pronounced for mixed-halide (e.g., red and blue) perovskite emitters in which critical challenges such as halide segregation and spectral instability are present. Here, we demonstrate bright and stable red PeLEDs based on mixed-halide perovskites, showing measured T 50 lifetimes of up to ∼357 h at currents of ≥25 mA cm –2, a record for the operational stability of visible PeLEDs under high current densities. The devices produce intense and stable emission with a maximum luminance of 28,870 cd m –2 (radiance: 1584 W sr –1 m –2 ), which is record-high for red PeLEDs. Key to this demonstration is the introduction of sulfonamide, a dipolar molecular stabilizer that effectively interacts with the ionic species in the perovskite emitters. It suppresses halide segregation and migration into the charge-transport layers, resulting in enhanced stability and brightness of the mixed-halide PeLEDs. These results represent a substantial step toward bright and stable PeLEDs for emerging applications.