Enhancement of the Efficiency in p-i-n Organic Light-Emitting Devices Containing Organic p-Type HAT-CN and n-Type Bis(ethylenedithio)-Tetrathiafulvalene Doped BPhen Layers

Abstract

The p-i-n organic light-emitting devices (OLEDs) were fabricated by using a p-type 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HAT-CN) layer and an n-type bis(ethylenedithio)-tetrathiafulvalene (BEDT-TTF) doped 4,7-diphenyl-1,10-phenanthroline (BPhen) electron transport layer. The p-i-n OLEDs containing a p-type HAT-CN layer and BEDT-TTF-doped BPhen layer with a BEDT-TTF doping concentration of 1 wt.% demonstrated low operating voltage and the highest luminance efficiency. The enhancement of the luminance efficiency as well as a decrease in the operating voltage of the OLEDs was attributed to the improvement of the hole and electron injection due to the insertion of a HAT-CN layer and a BEDT-TTF-doped BPhen layer.