Improved performance of fluorescent/phosphorescent hybrid white organic light-emitting diodes with enhanced chromatic stability utilizing bipolar interlayer

Abstract

Abstract Fluorescent/phosphorescent hybrid white organic light-emitting diodes (WOLEDs) employing a bipolar CBP interlayer with different thickness have been fabricated. The two-color hybrid WOLEDs at the optimal interlayer thickness exhibit a maximum efficiency of 11.47 cd A−1. Compared with the device without a CBP interlayer, the efficiency of the device is increased by 38.5% and the chromatic stability is also improved. This work found that appropriate thickness of the CBP interlayer with a higher triplet energy level can effectively block the Dexter energy transfer between the phosphorescent and fluorescent layers, which can reduce the energy of triplet in the exciton recombination zone and improve the efficiency of the device. Furthermore, the introduction of the bipolar interlayer with a suitable energy level adjusts the balance of exciton distribution, thereby achieving white light emission with good color stability. The present research could provide valuable strategy in developing hybrid WOLEDs with stable chromaticity.