CdSe胶质量子点的电致发光特性研究

采用胶体化学法合成硒化镉(CdSe)胶质量子点, 在此基础上制成了以CdSe胶质量子点为有源层, 结构为ITO/ZnS/CdSe/ZnS/Al的电致发光(EL)器件. 透射电镜测量表明量子点的尺寸为4.3 nm, 扫描电子显微镜测量ZnS薄膜和Al薄膜结果显示表面均较为平整, 由器件结构的X射线衍射分析观察到了CdSe(111)、ZnS(111)等晶面的衍射, 表明器件中包含了CdSe量子点和ZnS绝缘层材料. 光致发光谱表征胶质量子点的室温发光峰位于614 nm, 电致发光测量得到器件在室温下的发光波长位于450 ~ 850 nm, 峰值在800 nm附近. 本文对电致发光机制及其与光致发光谱的区别进行了讨论.

Electroluminescent Characteristics of CdSe Colloidal Quantum Dots

Electroluminescent (EL) devices with an ITO/ZnS/CdSe/ZnS/Al structure were fabricated using chemically synthesized colloidal CdSe quantum dots (QDs) as active layer. The size of the CdSe QDs is about 4.3 nm measured by a transmission electron microscope. Scanning electron microscope characterization shows smooth surfaces of ZnS layers and Al electrodes. CdSe (111) and ZnS (111) diffraction peaks are observed in the X-ray diffraction patterns, verifying the incorporation of CdSe QDs and ZnS insulator materials in the devices. Room temperature photoluminescence (PL) spectra reveal that the CdSe QDs’ emission peak is located at 614 nm. EL measurements at room temperature show a broad emission band ranging from 450 nm to 850 nm with a peak wavelength located at about 800 nm. Finally, the light emitting mechanism for the EL devices is proposed and the discrepancy between PL and EL spectra is interpreted.