Dipole Engineering in Charge Generation Interface for Fully Solution‐Processed and PEDOT:PSS‐Free Tandem Quantum‐Dot Light‐Emitting Diodes

Abstract Tandem quantum‐dot light‐emitting diodes (QLEDs) have attracted considerable attention in optoelectronics due to their potential for high efficiency and stability in display applications. A critical component in these devices is the charge‐generating layer (CGL), which commonly employs PEDOT:PSS for its hole injection properties and compatibility with solution processing, despite limitations related to acidity and orthogonal solubility. Phosphomolybdic acid (PMA) has emerged as a promising alternative, but its practical application is hindered by inherent oxidation and low work function. In this work, a dipole‐engineered CGL is reported by chemically anchoring ammonium acetate (AMA) layers at the charge generation interface between PMA and the hole‐transporting layer. AMA incorporation effectively suppresses PMA oxidation, enhances work function, and improves energy‐level alignment, which favors efficient charge separation within the CGLs. Furthermore, the AMA‐coated PMA surface exhibits strong resistance to solvent damage during subsequent solution processing. As a result, fully solution‐processed tandem QLEDs with AMA‐modified CGLs achieve a 200% improvement in electroluminescent efficiency compared to single‐emissive‐layer devices. This substantial efficiency improvement highlights the potential of dipole engineering in CGL design and offers valuable insights for developing high‐efficiency optoelectronic devices.