Highly efficient organic-inorganic hybrid light-emitting diodes by surface engineering

Abstract

Highly efficient inverted organic-inorganic light-emitting diodes require well-matched energy levels according to the device configurations, a reduction of interfacial resistance and passivation of the defect sites. In this paper, we present a simple and effective method of interfacial engineering by employing a series of amine-based polar solvents (ABPSs) that contain amine groups to enable adjustment of the work function (WF), which can be used to control the desired energy level depending on the number of amine groups. In addition, treatment with an ABPS can reduce the leakage current and enhance hole-blocking behavior via the passivation of defect sites on the ZnO surface. Thus, optimized inverted organic-inorganic light-emitting diodes with ABPS treatment achieve a luminous efficiency (LE) of around 23 cd A-1 using super yellow and power conversion efficiency (PCE) of 9.04 %, respectively.