Air-processed CuSCN hole-injection layer with improved surface properties for performance enhancement of quantum dot light-emitting diodes

Copper (I) thiocyanate (CuSCN) is a highly promising hole-injection layer (HIL) for optoelectronic devices due to its excellent hole mobility, optical transparency, and solution-processability. However, challenges related to defect states and film quality persist. This study presents a simple strategy for air-induced surface chemical restructuring of CuSCN films, effectively reducing surface defects and increasing covalent character. Results show that quantum-dot light-emitting diodes (QLEDs) fabricated with air-processed CuSCN HIL demonstrate approximately two-fold improvements in both brightness and efficiency compared to devices made in nitrogen atmospheres. These findings offer valuable insights for the development of cost-effective, high-brightness QLEDs, applicable across various transport layer systems.