The low efficiency and fast degradation of devices from ink-jet printing process hinders the application of quantum dot light emitting diodes on next generation displays. Passivating the trap states caused by both anion and cation under-coordinated sites on the quantum dot surface with proper ligands for ink-jet printing processing reminds a problem. Here we show, by adapting the idea of dual ionic passivation of quantum dots, ink-jet printed quantum dot light emitting diodes with an external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours were reported for the first time. The liquid phase exchange of ligands fulfills the requirements of ink-jet printing processing for possible mass production. And the performance from ink-jet printed quantum dot light emitting diodes truly opens the gate of quantum dot light emitting diode application for industry.

A PbI₂–(CsI)_0.15–(FAI)_x intermediate complex associated with preheating enables air-processed, high-efficiency Cs_0.15FA_0.85PbI₃ PSCs for the first time.

Charge transfer (CT) states induced by physisorbed N₂ on ZnO NPs are non-radiative whereas those induced by chemisorbed O₂ are radiative.