Cadmium-free quantum dots based violet light-emitting diodes: High-efficiency and brightness via optimization of organic hole transport layers
Cadmium-free quantum dots based violet light-emitting diodes: High-efficiency and brightness via optimization of organic hole transport layers
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基于无镉量子点的紫色发光二极管：通过优化有机空穴传输层实现高效率和高亮度
DOI：
10.1016/j.orgel.2015.06.032
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发表时间：
2015-10-01
影响因子：
3.2
通讯作者：
Li, Lin Song
中科院分区：
文献类型：
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作者：
Lin, Qingli;Shen, Huaibin;Li, Lin Song
通过选择不同的空穴传输层，包括聚（4-丁基苯基-二苯基胺）（聚- tpd）、聚[9,9-二辛基芴-co- n -[4-（3-甲基丙基1)]-二苯胺]（TFB）和聚- n -乙烯基咔唑（PVK）），证明了无重金属ZnSe/ZnS的紫色量子点（QD）发光二极管（QD- led）的明亮和高效。当poly-TPD用作html时，紫色qd - led的最大亮度约为930 cd/m(2)，最大电流效率为0.18 cd/A， EQE峰值为1.02%。利用TFB作为空穴输运材料，可以制备出更高亮度、低导通电压（3.8 V）的紫色qd - led。虽然最大亮度可达2691 cd/m(2)，但器件的电流效率较低（约0.51 cd/A）， EQE较低（约2.88%）。如果使用PVK作为空穴传输材料，与使用TFB相比，可以制造出更低的最大亮度和更高的导通电压的高效紫色qd - led。因此，采用一定比例的TFB和PVK混合物作为HTL，导通电压、亮度和效率都有了很大的提高。该qd - led的EQE为7.39%，最大亮度为2856 cd/m(2)， FWHM小于21 nm。这些结果表明，在效率、亮度和色彩纯度方面，无重金属紫色qd - led的性能有了显著改善。(C) 2015 Elsevier B.V.版权所有
Bright and efficient violet quantum dot (QD) based light-emitting diodes (QD-LEDs) with heavy-metal-free ZnSe/ZnS have been demonstrated by choosing different hole transport layers, including poly(4-butyl-phenyl-diphenyl-amine) (poly-TPD), poly[9,9-dioctylfluorene-co-N-[4-(3-methylpropy l)]-diphenylamine] (TFB), and poly-N-vinylcarbazole (PVK). Violet QD-LEDs with maximum luminance of about 930 cd/m(2), the maximum current efficiency of 0.18 cd/A, and the peak EQE of 1.02% when poly-TPD was used as HTL. Higher brightness and low turn-on voltage (3.8 V) violet QD-LEDs could be fabricated when TFB was used as hole transport material. Although the maximum luminance could reach up to 2691 cd/m(2), the devices exhibited only low current efficiency (similar to 0.51 cd/A) and EQE (similar to 2.88%). If PVK is used as hole transport material, highly efficient violet QD-LEDs can be fabricated with lower maximum luminance and higher turn-on voltages compared with counterpart using TFB. Therefore, TFB and PVK mixture in a certain proportion has been used as HTL, turn-on voltage, brightness, and efficiency all have been improved greatly. The QD-LEDs is fabricated with 7.39% of EQE and 2856 cd/m(2) of maximum brightness with narrow FWHM less than 21 nm. These results represent significant improvements in the performance of heavy-metal-free violet QD-LEDs in terms of efficiency, brightness, and color purity. (C) 2015 Elsevier B.V. All rights reserved.