Effect of refractive index matching layers on optical and electrical properties of top-emitting organic white light emitting devices

In order to analyze the effect of different thickness of C60 on optical and electrical properties of top-emitting OLED, in experiment, the transmittance of ETL/EIL/Mg:Ag/matching layers were numerically calculated and two top OLED with common cathode configurations were fabricated. The optical and electrical properties of OLED devices prepared with different thickness of C60 refractive index matching layers were analyzed. The results showed, the complex films with different C60 thickness have different transmittance, the complex films have high transmittance in wide range of wavelengths when C60 film thickness is 30~40 nm, the CIEx and CIEy values of transmittance spectra are extremely near to the equal energy (0.33, 0.33). In addition, it can be found that the electroluminescence spectra and the chromaticity coordinates of OLED devices are also heavily related to the thickness of C60 refractive index matching layers, which is consistent with the numerical results of transmission spectrum of multilayer (ETL/EIL/Mg:Ag/C60) at different thickness of C60 thin films and indicate that the luminous brightness and the color coordinates of top-emitting white light devices can be adjusted by different thickness of C60 refractive index matching layer to achieve white light emission close to equal energy.