Violet Light-Emitting Diodes Based on p‑CuI Thin Film/n-MgZnO Quantum Dot Heterojunction

• Published in: ACS applied materials & interfaces Vol. 12; no. 5; pp. 6037 - 6047
• Main Authors: Baek, Sung-Doo, Kwon, Do-Kyun, Kim, Yun Cheol, Myoung, Jae-Min
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 05-02-2020
• Subjects: p-CuI thin film; n-MgZnO quantum dot; heterojunction; device optimization; violet light-emitting diode
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.9b18507

As the lighting technology evolves, the need for violet light-emitting diodes (LEDs) is growing for high color rendering index lighting. The present technology for violet LEDs is based on the high-cost GaN materials and metal–organic chemical vapor deposition process; therefore, there have recently been intensive studies on developing low-cost alternative materials and processes. In this study, for the first time, we demonstrated violet LEDs based on low-cost materials and processes using a p-CuI thin film/n-MgZnO quantum dot (QD) heterojunction. The p-CuI thin film layer was prepared by an iodination process of Cu films, and the n-MgZnO layer was deposited by spin-coating presynthesized n-MgZnO QDs. To maximize the performance of the violet LED, an optimizing process was performed for each layer of p- and n-type materials. The optimized LED with 1 × 1 mm2-area pixel fabricated using the p-CuI thin film at the iodination temperature of 15 °C and the n-MgZnO QDs at the Mg alloying concentration of 2.7 at. % exhibited the strongest violet emissions at 6 V.