Abstract We fabricated and studied the operation characteristics of light emitting devices (LEDs) based on green CdSe/ZnS quantum dots (QDs). A series of devices with different concentrations of QDs in toluene showed typical electroluminescence (EL) peaks that are consistent with green photoluminescence of colloidal QDs emitting layer (EML), but their bandwidth were varied due to the parasitic emission originating from the adjacent organic layers. Upon the increase of the QD concentration, the contribution of the color contamination to emission light from QD-LED (QLED) devices was decreased resulting in the narrowing of EL spectra. On the other hand, the maximum efficiency of QLEDs increased in the lower QD concentration range, while decreased in the higher range. The optimum luminous efficiency of 1.22 cd/A and the external quantum efficiency of 0.43% at standard video brightness (200 cd/m2) was observed from the device with a QD concentration of 6 mg/ml which can be attributed to the enhanced charge recombination in QD EML.

中文翻译：

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量子点浓度对胶体量子点 LED 光电特性的影响

摘要 我们制作并研究了基于绿色 CdSe/ZnS 量子点 (QD) 的发光器件 (LED) 的工作特性。在甲苯中具有不同浓度 QD 的一系列器件显示出典型的电致发光 (EL) 峰，与胶体 QD 发射层 (EML) 的绿色光致发光一致，但由于来自相邻有机层的寄生发射，它们的带宽发生了变化。随着 QD 浓度的增加，颜色污染对 QD-LED (QLED) 器件发射光的贡献降低，导致 EL 光谱变窄。另一方面，QLED 的最大效率在较低 QD 浓度范围内增加，而在较高范围内下降。1.最佳发光效率