铜锌锡硫（CZTS）因其组成元素储量丰富、环境友好，且具有高的吸收系数和理想的带隙，成为新型薄膜太阳电池吸收层的理想材料。但是，目前铜锌锡硫薄膜太阳电池的发展主要集中在吸收层材料的制备，对于构成电池的p-n异质结缺乏研究，限制了高效电池的研发。本项目通过数值模拟，优化薄膜制备工艺，掌握组分掺杂对CZTS吸收层带隙的调控，系统研究CZTS薄膜内带隙分布与器件性能之间的关系，以及CZTS与不同n-型材料构成异质结间的导带带阶，弄清CZTS薄膜电池异质结能带匹配问题；研究CZTS太阳电池中p-n异质结的界面结构及其与太阳电池的性能之间的关系。通过本项目的研究，可以弄清铜锌锡硫薄膜太阳电池的异质结结构、能带及界面等科学问题，深入认识CZTS太阳电池中p-n异质结与太阳电池性能之间的关联，丰富多元化合物薄膜太阳电池异质结理论，为研制新型高效CZTS太阳电池提供指导，推动CZTS薄膜太阳电池的发展。

Cu2ZnSnS4 (CZTS) is an ideal materials as the absorber layer in thin film solar cells because of its good properties, such as notoxic, high absorption coefficients and proper energy band gap. However, the present research on CZTS solar cell is mainly focused on the film growth, and absence for the p-n heterojunction in solar cell, which is crucial for the development of CZTS solar cell with high conversion efficiency. In this proposal, the growth process of CZTS absorber is first optisized based on the simulation results to undersand the mechanics of energy band gap of CZTS adjusted by tunable composition. Then, the energy band gap engineering, including the gradient of energy band gap in CZTS absorber and the conduction band offset between CZTS and n-type semiconductor film, and their effects on the properties of solar cell is studied in detail. In addition, the interface of p-n heterojunction and the relation between the interface and properties of CZTS solar cell is also studied. By the systematic research designed in this proposal, some key scientific questions can be make clear, such as heterojunction structure of CZTS solar cell, energy band gap and interfaces. The relation between heterojunction structure of CZTS solar cell and the properties of CZTS solar cells can be get a further understand, which can promote the research of CZTS solar cells with high conversion efficiency.