摻雜低折射率材料提升高分子有機發光元件的光萃取效率

Abstract

我們在高分子綠色磷光發光二極體的主動層中摻入低折射率高分子材料Poly(2,2,3,3,3-pentafluoropropyl methacrylate) (PPFPMA)，透過改變有機層材料的折射率改變弱共振腔元件的共振條件，使共振波長更靠近有機發光體的本質放光頻譜的中心波長位置，增强元件內部的光學共振效應，提升元件的正向出光量和光萃取效率。摻雜0.1wt% PPFPMA之後，元件基本的電性、電激發光光譜和寿命幾乎沒有改變，而發光效率從20.5 cd/A提升20%至24.6 cd/A，功率效率從9.2 lm/W同樣提升20%至11 lm/W.

By blending low refractive index polymer, poly(2,2,3,3,3-pentafluoropropyl methacrylate) (PPFPMA), into the active layer of green phosphorescent polymer light-emitting diodes, substantial enhancement in forward luminance and light out-coupling could be obtained. The resonant wavelength of the weak microcavity devices was blue-shifted accompanied with a decrease in refractive indices of the organic layers. Optical resonance within cavity was enhanced when the resonant wavelength blueshifted and became closer to the peak of intrinsic emission wavelength of the organic emitters. The device containing 0.1wt% PPFPMA exhibited almost identical electrical characteristics, emission spectra and operational lifetime in comparison with the control device. The luminous efficiency was enhanced from 20.5 cd/A to 24.6 cd/A, the power efficiency was also enhanced from 9.2 lm/W to 11 lm/W.