Enhanced performance of all-inorganic QLED using double heat treatment of NiO HTL

Abstract

A double heat treatment scheme, crystallization heat treatment at elevated temperatures followed by vacuum annealing treatment at lower temperatures, was introduced to form a crystalline NiO single phase as well as surface phases with reduced defect concentration. With the modification of processing conditions, the luminance of QLED with the NiO HTL was improved from 30 cd /m2 to 11,500 cd /m2 and the current efficiency from 0.25 cd/A to 23 cd/A, respectively. © 2020 ITE and SID.