| 초록 |
Development of InP quantum dots (QDs) has opened cutting-edge display technology employing QDs as color converter. However, advance toward electrically-driven QD-based light-emitting diodes (QLEDs) has been lagging behind market expectations due to poor operation stability as well as efficiency. Recently, we unraveled the charge injection mechanism in QLEDs, where energy level alignment induced by Fermi level (EF) of QDs provides positive incentive on hole injection process. Despite successful charge injection, it seems to leave latent issue on the degradation of device constituents by charge accumulation at interfaces. Here, we tackle this issue by modifying surface chemistry of QDs, a pivotal gauge determining EF of QDs. Using time-resolved spectroscopy, we discriminate the EF change of QDs from energy band landscape, complicated by QD charging. We propose that the optimal EF can minimize charge accumulation at interfaces and result in enhanced device efficiency and stability. |
