Eco-Friendly White Quantum-Dot Light-Emitting Diodes Enabled by Multifunctional Polymer Hole-Transporting Materials

White light-emitting diodes (WLEDs) based on quantum dots (QDs) are promising for lighting and display technology. Blending organic polymers with QDs is an effective strategy for creating stable and efficient WLEDs. However, the interactions and energy transfer mechanisms internal to the mixed emitting layers are not fully understood. In this work, we developed multifunctional polymer hole transport materials (HTMs) with polyethylene glycol (PEG) side chains, named XP7 and XP8. When blended with eco-friendly ZnCuGaSe/ZnS QDs to fabricate WLEDs, these HTMs play multiple roles: they serve as blue-emitting components, enhance hole transport, passivate Zn-related defects on the QD surfaces, and improve Förster resonance energy transfer (FRET) from the polymer to the QDs. The resulting WLEDs achieve a well-balanced white emission spectrum with a maximum external quantum efficiency (EQE) of 1.68% and excellent operational stability. This study highlights the potential of integrating specifically designed polymer HTMs with eco-friendly QDs for advancing high-performance, sustainable WLEDs.