"Revitalizing Science and Engineering": HBU Physics Team Achieves Breakthrough in High-Efficiency Pure-Red Perovskite LEDs

Recently, the Organic Perovskite Photovoltaics Team at the College of Physical Science and Technology, Hebei University, made significant progress in high-efficiency pure-red perovskite light-emitting diodes (PeLEDs). The related research, titled *"Promoting Phase Transition in Quasi-2D Perovskites for High-Performance Pure-Red LEDs,"* was published in the top-tier international journal Advanced Materials (2025, 202503704), with Hebei University as the first affiliation. Master's students Yu Ao and Wang Jianglong served as co-first authors, while Associate Professor Liu Zhenyang and Dr. Sun Changjiu were corresponding authors.

Layered quasi-two-dimensional (quasi-2D) halide perovskites are a promising platform for developing efficient pure-red light-emitting devices. The optoelectronic performance of quasi-2D perovskites depends on their multi-quantum well distribution. Precise control over this distribution—suppressing wide-bandgap 2D phases while enhancing phase homogeneity—is critical to achieving quasi-2D perovskite films with flattened energy bands, low energy loss, and high radiative recombination efficiency.This study revealed that the broad phase distribution in solution-processed quasi-2D perovskite films stems from inefficient dynamic conversion from low-n to high-n phases. To address this, the team proposed an acetate-coordinated anion modulation strategy. By establishing a competitive coordination mechanism among acetate ions, bulky spacer cations, and inorganic layers, the approach synergistically promotes both the directional intercalation of bulky spacers and the dynamic conversion of wide-band gap 2D phases. This strategy significantly improved the luminescence purity, energy transfer efficiency, and photoluminescence quantum yield (PLQY) of quasi-2D perovskite films. The optimized pure-red PeLEDs exhibited narrowband emission at 641 nm with a record peak external quantum efficiency (EQE) of 25.3%. Notably, the method demonstrated excellent wavelength universality, offering a generalizable solution for high-performance PeLEDs across the entire visible spectrum.

The work was supported by the National Natural Science Foundation of China, the Hebei Provincial Natural Science Foundation, Hebei University’s High-Level Talent Recruitment Program, and the Public Testing Center of the College of Physical Science and Technology.

Full Paper: https://doi.org/10.1002/adma.202503704