Improved performance of all-inorganic quantum-dot light emitting diodes with an all-solution process at low temperature

Abstract

Organic light-emitting diode (OLEDs) displays have a widely application, but their inherent instability of devices, such as burn-in, short lifetime and poor stability are still critical drawbacks. Here, the all-inorganic quantum dots light-emitting diode (QLEDs) based on the all-solution process method at a lower temperature is developed. A simple strategy is engineered by introducing multi-times UV-ozone treatment during the Mg-NiO layer spin coating to enhance the hole injection for QLED device. The fabricated conventional QLED shows an improved EQE of 3.73 %, which is 2.2 times improved than the one without UV-ozone treatment. In addition, the inverted all-inorganic LED exhibits a maximum EQE of 2.63 % with a luminance of 3,640 cd m−2. The enhancement can be concluded that UV-ozone treatment creates nonstoichiometry in NiO, resulting in Ni3+ vacancy defects, which lowers valence band of Mg-NiO and enhance the hole injection.