Highly efficient OLED device based on the double emissive layer with an EQE about 39%

Abstract

Computational simulation study for dual –active scheme OLED (organic light-emitting diode) is validated with the attribution of two colors: firstly, BEPP which functions as fluorescence emission layer and secondly TCTA: Ir(ppy)3 as phosphorescent emission layer (TCTA: Ir(ppy)3) for intensifying the exciton operation. The device architecture for the OLED is further improved with the accreditation of doubly active layers exhibiting the maximum external quantum efficiency (EQE) upto 39 % (D1 device) corresponding to CIE chromaticity coordinates (0.57, 0.42). The simulated device offers higher EQE than previously reported results of EQE about 30 % by Wang et al. [25]. Concurrently, the role of viewing angle is also observed on electroluminance emission, as the EL spectrum is redshifted by ∼ 6 nm and peaks are depicted at 508 nm and 600 nm wavelength with an increased viewing angle. However, at the condition of increasing viewing angle, FWHM also becomes wider, as it is the noticeable change in the intensity ratio between the two emission peaks of the device. Lastly, the effects of dipole orientation on optical emission are further studied as a function of ETL-TPBi thickness for isotropic, TM, and TE mode optical channels, respectively in air. The device outcoupled efficiency is found more sensitive for TM mode than the rest in the study. Therefore, the result suggests that the dual-active scheme significantly improved device performance and offers a better outcome for device fabrication.