Interfacial Engineering and Defect Passivation via Naphthalene Disulfonate-Modified NiOx to Improve the Stability of Perovskite Light-Emitting Diodes.

NiOx is an inorganic hole layer that is widely used in perovskite light-emitting diodes (PeLEDs). However, direct interfacial contact with the perovskite film induces severe photoluminescence quenching, and buried interface defects critically impede the PeLEDs from achieving excellent performance. In this paper, S = O and Na+ are engineered to form coordination bonds and ionic bonds with defect sites at the buried interface of the perovskite film by providing lone pair electrons and Coulomb force to reduce the nonradiative recombination loss. The effects of different sodium naphthalene disulfonates on the passivation of perovskite films and the performance of PeLEDs were studied. The results show that the perovskite film prepared on the sodium 2,7-naphthalene disulfonate (DS2-7NA) substrate achieves excellent passivation, effectively avoiding direct contact with NiOx. Consequently, the green emission Quasi-2D PeLEDs exhibit an external quantum efficiency (EQE) exceeding 10%, a maximum brightness of approximately 6000 cd m-2, and an extended operational stability of 181.9 min under external environmental conditions.