| Autor: |
Deng, Yunzhou, Lin, Xing, Fang, Wei, Di, Dawei, Wang, Linjun, Friend, Richard H., Peng, Xiaogang, Jin, Yizheng |
| Rok vydání: |
2020 |
| Předmět: |
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| Zdroj: |
Nature Communications 11, 2309 (2020) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1038/s41467-020-15944-z |
| Popis: |
Electroluminescence (EL) of colloidal nanocrystals promises a new generation of high-performance and solution-processable light-emitting diodes (LEDs). The operation of nanocrystal-based LEDs relies on the recombination of electrically-generated excitons. However, a fundamental question, i.e, how excitons are electrically generated in individual nanocrystals, remains unanswered. Here, we reveal a molecular mechanism of sequential electron-hole injection for the exciton generation in nanocrystal-based EL devices. To decipher the corresponding elementary processes, we develop electrically-pumped single-nanocrystal spectroscopy. While hole injection into neutral quantum dots (QDs) is generally-considered to be inefficient, we find that the intermediate negatively-charged state of QD triggers confinement-enhanced Coulomb interactions, which simultaneously accelerate hole injection and hinder excessive electron injection. In-situ/operando spectroscopy on state-of-the-art QD-LEDs demonstrate that exciton generation at the ensemble level is consistent with the charge-confinement-enabled sequential electron-hole injection mechanism revealed at the single-nanocrystal level. Our findings provide a universal mechanism for enhancing charge balance in nanocrystal-based EL devices. |
| Databáze: |
arXiv |
| Externí odkaz: |
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