High‐Stability PEDOT:PSS‐Free QLEDs Enabled by Ti ₃ C ₂ T _x ‐Based Hole Injection Layer

ABSTRACT Quantum dot light‐emitting diodes (QLEDs) are promising for next‐generation displays and lighting due to their high color purity and wide color gamut. Poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is commonly used as the hole injection layer (HIL) in high‐performance QLEDs; however, its intrinsic acidity corrodes indium tin oxide (ITO) electrodes and induces In 3+ diffusion, which compromises interfacial stability, hole injection, and carrier balance in the devices. Herein, we present a PEDOT:PSS‐free strategy employing a highly conductive Ti 3 C 2 T x HIL modified with a self‐assembled monolayer of (2‐(3,6‐dimethoxy‐9H‐carbazol‐9‐yl)ethyl)phosphonic acid (MeO‐2PACz) to achieve highly stable QLEDs. The Ti 3 C 2 T x nanosheet component provides high electrical conductivity and a favorable energy level, while the MeO‐2PACz layer reduces film roughness and optimizes surface morphology, suppressing charge accumulation, leakage current, Joule heating, and non‐radiative recombination in the QLEDs. Red QLEDs fabricated with the Ti 3 C 2 T x /MeO‐2PACz HIL achieve a maximum external quantum efficiency (EQE) of 22.09% and a T 95 operational lifetime of 32 470 h at 1000 cd m −2 . This T 95 operational lifetime is approximately 2.97‐fold improvement compared with devices using PEDOT:PSS as the HIL, representing the most stable PEDOT:PSS‐free QLEDs reported to date. These findings that the Ti 3 C 2 T x /MeO‐2PACz HIL effectively enhances both efficiency and stability, offering a promising route toward high‐performance, durable QLEDs.