A collaborative team from the University of Science and Technology of China (USTC) of Chinese Academy of Sciences (CAS), led by Prof. YAO Hongbin, FAN Fengjia, LIN Yue, and HU Wei, has resolved a critical challenge in pure-red perovskite light-emitting diodes (PeLEDs) by identifying and addressing the root cause of efficiency loss at high brightness. Published in Nature on May 7, their study introduced a novel material design that enables record-breaking device performance, achieving a peak external quantum efficiency (EQE) of 24.2% and a maximum luminance of 24,600 cd m⁻²—the brightest pure-red PeLED reported to date.
Perovskite 3D heterostructure suppresses hole leakage in LEDs. (Image by USTC)
Pure-red PeLEDs, crucial for vivid displays and lighting, have long faced a trade-off between efficiency and brightness. While 3D mixed-halide perovskites like CsPbI₃₋ₓBrₓ offer excellent charge transport, their efficiency plummets under high current due to unresolved carrier leakage.
Using a self-developed diagnostic tool called electrically excited transient absorption (EETA) spectroscopy, the team captured real-time carrier dynamics in operating devices. They discovered that hole leakage into the electron transport layer—previously undetected due to a lack of in situ characterization methods—was the primary culprit behind efficiency roll-off.
To tackle this, the researchers engineered a 3D intragrain heterostructure within the perovskite emitter. This design embeds narrow-bandgap light-emitting regions within a continuous [PbX₆]⁴⁻ framework, separated by wide-bandgap barriers that confine carriers. Key to the strategy is the molecule p-Toluenesulfonyl-L-arginine (PTLA), which bonds strongly to the perovskite lattice via multiple functional groups (guanidino, carboxyl, amino, and sulfonyl).
PTLA expanded the lattice locally, creating wide-bandgap phases without disrupting structural continuity. High-resolution TEM and ultrafast spectroscopy confirmed seamless carrier transfer between the heterostructure’s phases and suppressed hole leakage.
The optimized PeLEDs exhibited unprecedented performance: at 22,670 cd m⁻²—nearly 90% of peak brightness—the EQE remained at 10.5%, far surpassing previous records. Stability tests revealed a half-lifetime of 127 hours at 100 cd m⁻², with minimal spectral shift during operation.
The team attributed this success to the heterostructure’s dual role: confining holes to the emitter while maintaining high carrier mobility through an uninterrupted 3D lattice.
This work bridges a critical gap in perovskite optoelectronics, combining advanced diagnostics with innovative material engineering. Reviewers hailed the study as “a landmark in perovskite LED research,” emphasizing its methodological rigor and transformative results.
Paper link: https://www.nature.com/articles/s41586-025-08867-6
(Written by WU Yuyang, Edited by HUANG Rui, USTC News Center)
