OLED 내부 광 추출 재료 합성 및 내부 광 추출 구조를 가지는 OLED의 제작

Abstract

In this study, the internal light extraction structure and materials for improving the efficiency of OLED were fabricated and applied to OLED device. At first, index matching materials were prepared to prevent light loss due to waveguide mode attributed to refractive index difference between ITO and glass. For the high refractive index materials were synthesized inorganic and organic-inorganic hybrid type, respectively. high refractive index organic materials were synthesized by introducing carbazole group into polymer back bone, the organic-inorganic hybrid material were prepared by introducing nano size metal oxide such as TiO2, ZrO2 into polymer matrix. Second, the internal light extraction layer was fabricated to reduce the total internal reflection effect by forming scattering or nano-structured layer in the flat OLED interface. The scattering layer was fabricated by dispersing TiO2 particles of 250 nm size in a polymer matrix using ball milling and optimum dispersion conditions were established by considering various parameters of ball milling. In the case of nano-structured layer, a dispersion of metal oxide nanoparticles or spontaneous phase separation of blend materials were used to obtain a non-uniform surface. Finally, each obtained internal light extraction materials and structures were applied to the OLED device and the improvement of the efficiency was analyzed.