Embankment protection-inspired interfacial engineering for ultrahigh-efficiency, stable tandem quantum dot light-emitting devices

A novel interfacial engineering inspired by the architecture of embankment protection is developed for CGL of tandem QLEDs. • The honeycomb oleophilic ZnO mesh effectively mitigates solvent-induced interfacial erosion and modulates charge generation. • The tandem QLEDs with modulated CGL achieve a high external quantum efficiency of 48.4% with a low turn-on voltage of 3.0 V. The efficiency and stability of tandem quantum dot light-emitting devices (QLEDs) are predominantly governed by the interfacial properties of the charge generation layer (CGL). As a promising CGL candidate, the ZnO/PEDOT:PSS heterostructure is plagued by severe interfacial erosion induced by non-orthogonal solvents during solution processing. Herein, we propose a novel interfacial engineering strategy inspired by the embankment protection principle, constructing a honeycomb-patterned oleophilic ZnO (o-ZnO) mesh as a protective barrier atop the alcohol-dispersible ZnO film. This o-ZnO mesh not only effectively mitigates solvent-induced interfacial erosion but also ensures efficient charge transport, resolving the long-standing trade-off between interfacial compatibility and charge generation. Systematic characterizations confirm that the optimized CGL enables precise modulation of charge generation efficiency via tunable geometric parameters of the o-ZnO mesh. As a result, the tandem QLED achieves a high external quantum efficiency of 48.4% with a low turn-on voltage of 3.0 V, and an operational T 95 lifetime (at a luminance of 1000 cd cm −2 ) extended to 11,445 h, which is 6 times longer than that of the control device. This work not only provides a versatile solution to the solvent compatibility issue in solution-processed tandem QLEDs but also establishes a new paradigm for interfacial engineering in optoelectronic devices.