State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China.
Nanoscale. 2013 Apr 21;5(8):3474-80. doi: 10.1039/c3nr34168b. Epub 2013 Mar 11.
We demonstrated the fabrication of inverted CdSe/CdS/ZnS quantum dot light emitting devices (QD-LEDs) using titanium dioxide (TiO2) as an electron-injection layer and investigated the operating mechanism by utilizing different hole-transport materials, 4,4-N,N-dicarbazole-biphenyl (CBP) and 4,4',4''-tris(carbazol-9-yl)-triphenylamine (TCTA). A more efficient device with CBP as the hole-transport layer (HTL) was obtained compared with the TCTA based device. The peak efficiency of 6.70 cd A(-1) for the CBP based device was found to be about 74.5% higher than the TCTA based device (3.84 cd A(-1)). The studies on the time-resolved photoluminescence spectra of the QD-HTL composite structures showed that the energy transfer (ET) efficiencies from the two HTLs to the QD layer were similar and the charge separation between QDs and HTLs could be neglected. The enhancement in the performance of the CBP based device was attributed to the more efficient hole-injection from CBP to QDs.
我们展示了使用二氧化钛 (TiO2) 作为电子注入层来制造倒置 CdSe/CdS/ZnS 量子点发光二极管 (QD-LED)，并利用不同的空穴传输材料，即 4,4-N,N-二咔唑联苯 (CBP) 和 4,4',4''-三(咔唑-9-基)三苯胺 (TCTA)，研究了其工作机制。与基于 TCTA 的器件相比，使用 CBP 作为空穴传输层 (HTL) 的器件具有更高的效率。基于 CBP 的器件的峰值效率为 6.70 cd A(-1)，比基于 TCTA 的器件 (3.84 cd A(-1)) 高约 74.5%。对 QD-HTL 复合结构的时间分辨光致发光光谱的研究表明，来自两个 HTL 的能量转移 (ET) 效率相似，并且可以忽略 QD 和 HTL 之间的电荷分离。基于 CBP 的器件性能的增强归因于 CBP 向 QD 更有效的空穴注入。
