Enhancement of Optical Efficiency in White OLED Display Using the Patterned Photoresist Film Dispersed With Quantum Dot Nanocrystals

Quantum dot (QD) nanocrystals dispersed in photoresist (PR) film was developed and applied to white organic light-emitting diode (OLED) to improve optical power of red color through down-converting of blue and green light. To integrate to white OLED display panel, the QD dispersed photoresist film was prepared in a thickness of 2 μm with high concentration of QDs up to 30 wt%. QDs were dispersed successfully in PR with a matching of nonpolar characteristic for the ligands of QDs and PR as well as a careful mixing process of PR and QD dispersed solutions. We also realized the patterning of QD dispersed PR film with a stripe pattern of 60- μm width without a residual layer. The experimental measurement after passing through a 30 wt% QD dispersed PR film and a red color filter in white OLED shows the enhancement of 40.2% in the optical power of red color compared to that from a conventional white OLED without QD dispersed PR film.