Efficient Deep Blue Organic Light-emitting Diodes Based on Thermally Activated Delayed Fluorescence Emitter with Simplified Device Structure

Abstract

In this study, we have designed a series of blue electroluminescent (EL) devices with streamlined structures based on conventional electron transport materials. The incorporation of TcTa layer leads to a distinct improvement in the EL properties, which is attributable to the balanced distribution of the charge carriers and the extent of the recombination zones in the emission layer. In addition, it has been found that the auxiliary thickness of the stepwise TcTa layer is advantageous in order to improve the color purity of the device. Finally, device obtained the highest brightness, current efficiency, power efficiency, power efficiency and external quantum efficiency (EQE), reaching 3914 cd/m²,12.58 cd/A, 12.69 lm/W and 13.1% respectively. The color coordinates of the device are (0.176, 0.159), which are shown in dark blue..