Organic light-emitting diodes with enhanced out-coupling efficiency using high-refractive-index glass frit

We have fabricated a novel type of substrate for organic light-emitting diodes (OLEDs) to improve the light out-coupling efficiency. It was fabricated by forming an excellent flat layer using a high-refractive-index B2O3-SiO2-Bi2O3 frit glass on the light diffusive glass substrate. By using this substrate, we have sufficiently reduced the total internal reflection of OLEDs, and we successfully obtained more than 1.9 times higher light out-coupling efficiency without spectral changes and viewing angle dependency. Furthermore, we have also successfully demonstrated 50 x 50 mm large-area white OLEDs with this novel substrate.