Efficient Cadmium-Free Inverted Red Quantum Dot Light-Emitting Diodes
| Autor: | Hyung Choi, Raju Lampande, Chae Young Lee, Ji Eun Yeom, Jun Mo Yoo, Jang Hyuk Kwon, Nagarjuna Naik Mude, Sang Hyun Sohn, Kwan Ju Eun |
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| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
Quenching Materials science business.industry Exciton 02 engineering and technology Conductivity 021001 nanoscience & nanotechnology 01 natural sciences law.invention chemistry.chemical_compound chemistry Quantum dot law 0103 physical sciences Indium phosphide Optoelectronics General Materials Science Quantum efficiency 0210 nano-technology business Diode Light-emitting diode |
| Zdroj: | ACS Applied Materials & Interfaces. 11:36917-36924 |
| ISSN: | 1944-8252 1944-8244 |
| DOI: | 10.1021/acsami.9b12514 |
| Popis: | Here, we report an efficient inverted red indium phosphide (InP) comprising QD (InP/ZnSe/ZnS, core/shell structure) light-emitting diode (QLED) by modulating an interfacial contact between the electron transport layer and emissive InP-QDs and applying self-aging approach. The red InP-QLED with optimized interfacial contact exhibits a significant improvement in maximum external quantum efficiency and current efficiency from 4.42 to 10.2% and 4.70 to 10.8 cd/A, respectively, after 69 days of self-aging, which is an almost 2.3-fold improvement compared to the fresh device. The analysis indicates the consecutive reduction in electron injection and accumulation in the emissive QD due to changes in the conduction band minimum of ZnMgO (0.1 eV after 10 days of storage) through a downward vacuum-level shift according to the aging times. During the device aging periods, the oxygen vacancy of ZnMgO reduces, which leads to lower the conductivity of ZnMgO. As a result, charge balance of the device is improved with the suppression of exciton quenching at the interface of ZnMgO and InP-QD. |
| Databáze: | OpenAIRE |
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