Diverse Metal Ion Polyelectrolytes as Hole Transport Layers for Quasi‐2D Perovskite Light‐Emitting Diodes

Abstract This work investigates the role of metal ion‐doped (Cs + , Ni 2+ , and Cu 2+ ) PEDOT:PSS films as hole transport layers (HTLs) in quasi‐2D perovskite light‐emitting diodes (PeLEDs). These HTLs lead to enhanced device performance through reduced defect density, improved hole mobility, and prolonged photoluminescence lifetime. X‐ray diffraction (XRD) reveals structural modifications in CsPbBr 3 films, with enhanced crystallinity resulting from the elimination of excess long‐chain cations. Morphological analyses using scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrate the influence of metal doping on surface coverage and nanoscale roughness. Time‐resolved photoluminescence (TR‐PL) analysis confirms reduced nonradiative recombination, supporting improved film quality. Devices with Ni:PEDOT:PSS exhibit the highest external quantum efficiency, while Cs:PEDOT:PSS and Cu:PEDOT:PSS offer enhanced stability, achieving significantly longer operational lifetimes. These findings highlight the potential of metal‐doped PEDOT:PSS in optimizing the structural, optical, and electrical properties of perovskite materials, paving the way for more stable and efficient PeLEDs.