层状半导体材料纳米结构中激子分离动力学研究

层状半导体材料纳米结构因其在能源、光伏、光传感器件等领域展现出了巨大的应用前景而备受关注。如何高效、可控地实现激子分离是层状半导体材料发挥其性能和应用的关键科学问题。然而，激子分离的动力学过程和物理机制还缺乏全面且统一的认识。本项目拟研究层状半导体材料纳米结构中的激子分离动力学和外场调控机制。具体包括：1)通过改进的机械球磨法得到高质量的具备梯度尺寸的层状半导体材料纳米结构,研究其激子分离动力学; 2)利用泵浦-探测超快光谱给出属于激子分离过程的谱学判据，并结合理论计算描绘出驱动激子分离的具体物理机制; 3)在明确物理机制的基础上，研究环境介电常数、应力、电场对激子分离动力学过程的影响，实现对激子分离过程速率和效率的调控。该项目的实施不仅可以深入研究激子分离的物理机制及性能调控，同时为层状半导体材料纳米结构光催化、光伏、光传感器等功能的优化和应用奠定基础。

Layered semiconductor nanostructures have attracted much attention due to their great prospects in the fields of energy, photovoltaics, and light sensor devices. Herein, separation of excitons with efficiency and controllability is a key issue which determines the performance of layered semiconductor nanostructures. However, a comprehensive understanding of the dynamic process and physical mechanism of exciton separation are still lacking. This project is based on layered semiconductor nanostructures to study the physical mechanism of exciton separation dynamics, and external field regulation to manipulate exciton separation. The contents as follows: 1) preparing high-quality, gradient sized layered semiconductor nanostructures through improved mechanical ball milling method for studying the exciton separation kinetics; 2) determine the spectroscopic criterion for the exciton separation process based on transient absorption spectroscopy, and describe the specific physical mechanism driving the exciton separation combined with theoretical calculations; 3) study the influence of environmental dielectric constant, stress and electric field regulation on the exciton separation dynamics and realize the manipulation of exciton separation rate and efficiency. The implementation of the project can not only deeply understand the physical mechanism and performance regulation of exciton separation, but also lay a foundation for the optimization and application of the functions of layered semiconductor materials, such as photo-catalysis, photovoltaic and optical sensors.