Interfacial engineering with a 2PACz self-assembled monolayer for efficient CuSCN-based quantum dot light-emitting diodes.

We demonstrate interfacial engineering using [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz) self-assembled monolayers at the ITO/CuSCN interface to enhance quantum dot light-emitting diode (QLED) performance. X-ray and ultraviolet photoelectron spectroscopy confirm phosphonate anchoring and work-function tuning, reducing the hole-injection barrier. The optimized QLED achieves a turn-on voltage of 2.5 V (down from 2.8 V) and a maximum current efficiency of 18.2 cd/A, representing a 42% enhancement over the control device. This interfacial modification suppresses leakage while improving hole injection, providing a practical strategy for efficient CuSCN-based QLEDs.