A groundbreaking discovery from a team at the University of Science and Technology of China (USTC) has shattered barriers in pure-red perovskite light-emitting diodes (PeLEDs), setting the stage for a dazzling future in display technology.

Their research, recently published in the prestigious journal Nature, unveiled a cutting-edge material design that has achieved an astonishing external quantum efficiency (EQE) of 24.2% and a record maximum luminance of 24,600 cd m-2, marking the brightest pure-red PeLED to date.

Breaking the Efficiency and Brightness Dilemma!

Pure-red PeLEDs hold the key to vibrant displays and effective lighting solutions, yet they have long been plagued by a frustrating trade-off between efficiency and brightness. Traditional 3D mixed-halide perovskites, like CsPbI3-xBrx, excel in charge transport but suffer from significant efficiency drops at high current levels.

The researchers, led by Professors Yao Hongbin, Fan Fengjia, Lin Yue, and Hu Wei, turned the tide using an innovative diagnostic tool they developed called electrically excited transient absorption (EETA) spectroscopy. This technique allowed them to observe real-time carrier dynamics within the devices, revealing that hole leakage into the electron transport layer was the major culprit behind the drop in efficiency.

A Ingenious Solution: The 3D Intragrain Heterostructure!

To combat this leakage, the team engineered a remarkable 3D intragrain heterostructure that embeds narrow-bandgap light-emitting regions within a continuous framework, featuring wide-bandgap barriers that successfully contain the carriers.

At the heart of this innovation is the molecule p-Toluenesulfonyl-L-arginine (PTLA), which bonds robustly with the perovskite lattice, effectively expanding the lattice locally. This strategic expansion created wide-bandgap phases without compromising structural integrity.

High-resolution transmission electron microscopy (TEM) and ultrafast spectroscopy confirmed that carrier transfer between the heterostructure's phases was seamless, drastically reducing hole leakage.

Astounding Results: A New Era for PeLEDs!

The optimized PeLEDs showcased extraordinary performance: at a luminance of 22,670 cd m-2—nearly 90% of the peak brightness—the EQE remained an impressive 10.5%, outclassing all previous standards. Furthermore, with a stability half-lifetime of 127 hours at 100 cd m-2, the devices exhibited minimal spectral shifts during operation.

The team's accomplishment is a testament to their clever design, which confines holes to the emitter while allowing high carrier mobility across a continuous 3D lattice.

A Milestone in Perovskite Research!

This pioneering work represents a leap forward in perovskite optoelectronics, merging advanced diagnostics with innovative material engineering to address long-standing challenges. Reviewers have praised the study as "a landmark in perovskite LED research," highlighting its methodological rigor and the transformative implications for future technology.

As the potential applications of this technology continue to unfold, the future of display and lighting solutions has never looked brighter!