Stepwise Bi-Layer Hole-Transport Interlayers With Deep Highest Occupied Molecular Orbital Level for Efficient Green Quantum Dot Light-Emitting Diodes
| Autor: | Xuyong Yang, Piaoyang Shen, Sheng Wang, Wang Xiaojun, Haoran Wang, Jianhua Zhang, Fan Cao, Qianqian Wu |
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| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
Materials science business.industry Charge (physics) Electron 01 natural sciences Electronic Optical and Magnetic Materials law.invention law Quantum dot 0103 physical sciences Optoelectronics Energy level Quantum efficiency Electrical and Electronic Engineering business HOMO/LUMO Light-emitting diode Diode |
| Zdroj: | IEEE Electron Device Letters. 40:1139-1142 |
| ISSN: | 1558-0563 0741-3106 |
| DOI: | 10.1109/led.2019.2916584 |
| Popis: | The imbalanced charge transport/injection in quantum dot (QD) light-emitting diodes (QLEDs) due to the existing excess electrons has greatly restricted the device performance. Here, we designed a stepwise bi-layer structured hole-transport layer (HTL) containing 4, $4^{\prime }$ -bis-(carbazole-9-yl)biphenyl (CBP)/1,3-bis(9H-pyrido[2,3-b]indol-9-yl) benzene (mCaP) with deep highest occupied molecular orbital (HOMO) level to realize more efficient hole injection into QD emissive layer for balancing charge in the QLED devices. The resulting green QLEDs show a maximum current efficiency (CE) of 41.2 cd A−1 corresponding to an external quantum efficiency (EQE) of 12.6%, which is a significant efficiency enhancement compared with the devices with only single-layer HTL. In addition, the device turn-on voltage is also reduced from 5 to 3 V, and meanwhile the operational lifetime is increased by more than twofold. |
| Databáze: | OpenAIRE |
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