Bipolar-shell resurfacing for blue LEDs based on strongly confined perovskite quantum dots
Autor: | Min-Jae Choi, Oleksandr Voznyy, Mahshid Chekini, Ya-Kun Wang, Eugenia Kumacheva, Yuan Liu, Dongxin Ma, Hinako Ebe, Se-Woong Baek, Yitong Dong, James Z. Fan, Zheng-Hong Lu, Rafael Quintero-Bermudez, Fanglong Yuan, Yi Hou, Liang-Sheng Liao, Sjoerd Hoogland, Edward H. Sargent, Laxmi Kishore Sagar, Bin Sun, Petar Todorović, Bin Chen, Filip Dinic, Makhsud I. Saidaminov, Andrew Johnston, Seungjin Lee, Peicheng Li, Hao Ting Kung, Erdmann Spiecker, Mingjian Wu |
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Rok vydání: | 2020 |
Předmět: |
Electron mobility
Photoluminescence Materials science business.industry Biomedical Engineering Quantum yield Bioengineering 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Atomic and Molecular Physics and Optics 0104 chemical sciences Ion Semiconductor Quantum dot Optoelectronics General Materials Science Quantum efficiency Electrical and Electronic Engineering 0210 nano-technology business Perovskite (structure) |
Zdroj: | Nature Nanotechnology. 15:668-674 |
ISSN: | 1748-3395 1748-3387 |
Popis: | Colloidal quantum dot (QD) solids are emerging semiconductors that have been actively explored in fundamental studies of charge transport1 and for applications in optoelectronics2. Forming high-quality QD solids—necessary for device fabrication—requires substitution of the long organic ligands used for synthesis with short ligands that provide increased QD coupling and improved charge transport3. However, in perovskite QDs, the polar solvents used to carry out the ligand exchange decompose the highly ionic perovskites4. Here we report perovskite QD resurfacing to achieve a bipolar shell consisting of an inner anion shell, and an outer shell comprised of cations and polar solvent molecules. The outer shell is electrostatically adsorbed to the negatively charged inner shell. This approach produces strongly confined perovskite QD solids that feature improved carrier mobility (≥0.01 cm2 V−1 s−1) and reduced trap density relative to previously reported low-dimensional perovskites. Blue-emitting QD films exhibit photoluminescence quantum yields exceeding 90%. By exploiting the improved mobility, we have been able to fabricate CsPbBr3 QD-based efficient blue and green light-emitting diodes. Blue devices with reduced trap density have an external quantum efficiency of 12.3%; the green devices achieve an external quantum efficiency of 22%. A solution-based ligand-exchange strategy enables the realization of close-packed quantum dot solid films with near-unity photoluminescence quantum yield and high charge carrier mobility. |
Databáze: | OpenAIRE |
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