# Synergistic Triplet Exciton Management and Interface Engineering for High-Brightness Sky-Blue Multi-Cation Perovskite Light-Emitting Diodes

## TL;DR

Researchers improved blue perovskite LEDs by managing triplet excitons and adjusting material composition, achieving high brightness and efficiency.

## Contribution

A synergistic strategy combining multi-cation engineering and triplet exciton management is introduced to enhance blue PeLED performance.

## Key findings

- Incorporating mCBP increased exciton binding energy from 49.36 meV to 68.84 meV.
- PeLEDs achieved a peak external quantum efficiency of 10.2% and luminance over 12,000 cd/m².

## Abstract

Perovskite light-emitting diodes (PeLEDs) have garnered significant interest owing to their exceptional color purity, broadly tunable emission spectra, and cost-effective solution processability. However, blue PeLEDs continue to underperform in efficiency and operational stability compared to their red and green counterparts, primarily due to defect-induced non-radiative recombination losses and inefficient exciton management. Herein, we demonstrate a synergistic approach that integrates multi-cation compositional engineering with triplet exciton management by incorporating a high-triplet-energy material, mCBP (3,3-Di(9H-carbazol-9-yl)biphenyl), during film fabrication. Temperature-dependent photoluminescence reveals that mCBP incorporation significantly enhances the exciton binding energy from 49.36 meV to 68.84 meV and reduces phonon coupling strength, indicating improved exciton stability and suppressed non-radiative channels. The corresponding PeLEDs achieve a peak external quantum efficiency of 10.2% and a maximum luminance exceeding 12,000 cd/m2, demonstrating the effectiveness of this solution-based triplet management strategy. This work highlights the critical role of scalable, solution-processed triplet exciton management strategies in advancing blue PeLED performance, offering a practical pathway toward high-performance perovskite-based display and lighting technologies.