QDs-MoS2异质结光电性质与其界面调控机制的单分子水平研究

Two-dimensional photodetectors of quantum dots (QDs) sensitized monolayer MoS2 have good development prospects due to the advantages of high absorption efficiency and adjustable response spectrum. It was found that the interface properties of QDs-MoS2 play an important role in the performance of the device, but the deep information associated with them is lacking. In this project, ZnSe/CdS QDs will be used to sensitized MoS2 to construct heterojunction devices with different interface structures or properties. The surface structure and properties of QDs can be changed by controlling the thickness of the shell, the type the length of surface ligands. And the carrier concentration or the surface properties of MoS2 can be controlled by changing the form and the range of the applied electric field. Single molecule techniques will be employed to investigate the following contents in situ and in real time at the single nanoparticle level: (1)The concentration, rate and transmission mechanism of the electron injection and the kinetic process of energy transfer between the QDs-MoS2 interfaces; (2) The effect of the carrier concentration gradient of the electric field controlled MoS2 on the charge / energy transfer efficiency between the interfaces. Combining the macroscopic photoelectric performance parameters，the correlation between the different interface properties and the performance of photodetector devices will be established, and thus contributes to deepen the understanding of the mechanism of the couplinng between QDs and MoS2. It is believed that the achievements of this project will also be of significance in providing the scientific basis for the construction of high-performance, wide-spectrum photodetectors.

量子点（QDs）敏化二维二硫化钼（MoS2）的异质结光电探测器件由于光吸收效率高、响应光谱可调等优点，具有良好的发展前景。研究发现，QDs-MoS2界面性质对器件的性能起重要作用，但缺乏两者关联的深层信息。因此，通过控制ZnSe/CdS QDs的尺寸、壳层厚度、表面配体种类或通过施加电场的形式和大小调控单层MoS2的表面性质，构筑不同界面结构、性质的异质结器件。利用单分子技术在单颗粒水平上原位、实时研究（1）QDs-MoS2界面间电子注入浓度、速率和传输机制及能量转移的动力学过程；（2）电场调控的MoS2载流子浓度梯度变化对界面间电荷/能量转移效率的影响。结合宏观光电性能参数，建立不同的界面结构、性质与光电探测器件性能之间的关系，加深对QDs与MoS2之间耦合作用机制的理解，为构筑高性能、宽光谱光电探测器件提供科学依据。

钙钛矿量子点（ CaPbBr3 QDs）光电探测器件由于光吸收效率高、响应光谱可调等优点，具有良好的发展前景。研究发现，QDs表面性质对器件的性能起重要作用，但缺乏两者关联的深层信息。因此，通过控制QDs的尺寸、表面配体浓度调控QDs的表面性质，构筑不同界面结构、性质的量子点/锌卟啉（CaPbBr3 QDs/ZnP）光电器件。利用单分子技术在单颗粒水平上原位、实时研究（1）QDs表面激子发射的动力学过程；（2）QDs-ZnP浓度变化对界面间能量转移效率的影响。结合宏观光电性能参数，建立不同的表面性质与光电探测器件性能之间的关系，加深对QDs与ZnP之间能量机制的理解，为构筑高性能、宽光谱光电探测器件提供科学依据。