高效碳量子点白光LED的制备及关键问题的研究

The nanomaterial-based light emitting diode with high efficiency is a hot topic in the field of solid lighting and display. Nontoxic nanomaterial-based LED has attracted more and more researchers' attention. Carbon dots are promising optoelectrnic material due to its advantages such as high quantum yield, nontoxity, easy process, low cost and so on. The purpose of this proposal is to improve the brightness and external quantum efficiency of carbon dot-based LED based on our previous research work. We propose to deeply investigate the recombination mechanism and carrier transport mechanism. First, we would like to investigate the synthesis method of high quality carbon dots and its optical property to show the surface and size-dependent optical property; second, the first principles are employed to set up the band energy model based on the transient absorption spectra and fluorescence dynamics; third, energy levels of device layers are tuned according to the band model of carbon dots to improve the carrier injecting property; finaly, the temperature-dependent I-V property is employed to analyze the device structure and layers' surface-related carrier transport machanism. Therefore, energy matching, carrier transport control and bilayer lighting are proposed to fabricate carbon dot-based white LED with high brightness and external quantum efficiency.

高效、无毒"绿色"纳米材料LED是照明和显示领域的重要发展方向之一，日益引起了研究者的高度关注。碳量子点不仅具有高荧光效率、无毒"绿色"等特点，并且制备工艺简单、价格低廉，是有应用前景的光电材料。在碳量子点LED初步研究工作基础上，本项目以提高其电致发光效率为目的，围绕碳量子点发光机理和LED中载流子输运机制两个科学问题，通过碳量子点可控制备，研究不同碳量子点的光学特性，揭示表面态及尺寸对碳量子点光学特性的影响规律；通过瞬态吸收和荧光动力学研究，结合第一性原理，建立碳量子点能级结构模型；进一步研究器件中层层能级结构调控方法，揭示载流子迁移层与碳量子点层间能级匹配对载流子注入特性的影响规律；通过碳量子点LED变温I-V特性研究，建立载流子迁移模型，揭示器件结构参数、层间界面性质与载流子输运特性的关系规律。进而利用能级匹配、载流子输运调控、补偿发光等方法，制备出高效碳量子点白光LED。

高效、无毒“绿色”纳米材料LED是照明和显示领域的重要发展方向之一，日益引起了研究者的高度关注。碳量子点不仅具有高荧光效率、无毒“绿色”等特点，并且制备工艺简单、价格低廉，是有应用前景的光电材料。在本项目研究中，我们以提高碳量子点发光二极管发光效率为目的，围绕碳量子点发光机理和LED中载流子输运机制两个科学问题，通过碳量子点可控制备，制备出三种特性的碳量子点材料，获得了激发波长依赖和不依赖的碳量子点发光材料，并研究不同碳量子点的光学特性，揭示表面态及尺寸对碳量子点光学特性的影响规律；通过瞬态吸收和荧光动力学研究，结合第一性原理，建立碳量子点能级结构模型，确定碳量子点胶体量子点多种辐射跃迁机制，实现碳量子点薄膜厚度、浓度调制发光颜色，制备出碳量子点显示薄膜器件和多种结构的碳量子点荧光型发光器件；进一步研究器件中层层能级结构调控方法，揭示载流子迁移层与碳量子点层间能级匹配对载流子注入特性的影响规律；通过碳量子点LED变温I-V特性研究，建立载流子迁移模型，揭示器件结构参数、层间界面性质与载流子输运特性的关系规律。进而利用能级匹配、载流子输运调控、补偿发光等方法，制备出多种结构的碳量子点电致发光器件，实现了注入电流调控发光颜色的LED。通过本项目的研究，我们发表SCI检索的学术论文40篇，其中通信作者SCI论文37篇，影响因子大于3.0的36篇，影响因子大于10.0的4篇；申请国家发明专利6项，获得授权发明专利4项；培养博士研究生4人，硕士研究生4人。