Chinese researchers revolutionize red perovskite LED performance with a new material design, achieving record brightness and efficiency—paving the way for next-gen display and lighting technologies.
A research team from the University of Science and Technology of China (USTC), under the Chinese Academy of Sciences (CAS), has achieved a major milestone in perovskite light-emitting diode (PeLED) technology. They developed a new material design for pure-red PeLEDs that delivers record-breaking performance, addressing a persistent challenge in the field—efficiency loss at high brightness levels.
Red PeLEDs are essential for vivid displays and advanced lighting applications but have long faced a trade-off: as brightness increases, efficiency typically drops. This is particularly true for 3D mixed-halide perovskites like CsPbI₃₋ₓBrₓ, which, while offering good charge transport, suffer from performance losses under strong current due to unresolved charge leakage issues.
Led by Prof. Yao Hongbin and colleagues, the team used a unique diagnostic technique—electrically excited transient absorption (EETA) spectroscopy—to observe carrier dynamics in real time. This allowed them to uncover the root cause of the efficiency decline: hole leakage into the electron transport layer, previously hidden due to lack of real-time detection methods.
To solve this, the researchers introduced a 3D intragrain heterostructure within the perovskite layer. This design embeds light-emitting narrow-bandgap regions within a continuous [PbX₆]⁴⁻ framework, separated by wide-bandgap barriers that effectively confine charge carriers.
Central to the advancement is the use of p-Toluenesulfonyl-L-arginine (PTLA), a molecule that binds tightly to the perovskite lattice and induces localized lattice expansion without compromising structural continuity. This enables efficient charge confinement and transfer, minimizing leakage. The result: a peak external quantum efficiency (EQE) of 24.2% and maximum luminance of 24,600 cd/m²—the highest ever recorded for pure-red PeLEDs. Devices maintained 10.5% EQE at 90% peak brightness and demonstrated excellent stability, with a half-lifetime of 127 hours at 100 cd/m².
