Hybrid Polyacrylamide-ZnO Electron Transport Layers; Enhancing Exciton Recombination and Charge Injection for High-Efficiency QLEDs

Abstract

ZnO nanoparticles (ZnO NPs) are widely utilized as electron transport layers (ETLs) in quantum dot light-emitting diodes (QLEDs) due to their high electron mobility, wide bandgap, excellent transparency, and effective hole blocking properties. However, exciton quenching at the interface between quantum dots (QDs) and ZnO NPs and unfavorable band alignment hinder the performance of QLED devices. In this study, a straightforward and versatile approach is introduced to fabricate high-performance QLED by incorporating Polyacrylamide (polyNIPAM) with ZnO NPs. The resulting QD and hybrid-ZnO NPs films achieved a photoluminescence quantum yield (PLQY) of 57.8% and a recombination rate of 80.07%. Compared to conventional ZnO-based QLEDs, the hybrid approach led to a significant improvement in external quantum efficiency (22.34%), maximum brightness (97 593 cd m⁻²), and a narrow full-width at half maximum (FWHM) of 22.3 nm. The hybrid ZnO NPs exhibited favorable energy levels for electron injection, promoting exciton recombination while minimizing charge diffusion losses at the QD/ZnO NP interfaces. These findings highlight the potential of polyNIPAM-functionalized ZnO NPs for scalable, high-performance QLED fabrication. Future work will focus on optimizing hybrid material composition to further suppress electron leakage and enhance charge transport 1in large-area devices.