光伏材料铜锑硫薄膜的电学输运机制研究

Due to the energy and environment problems, renewable energies, like photovoltaic technology, are developed quickly all over the world. Thin film solar cells, i.e. CIGS and CdTe, as two of the most popular photovoltaic technologies, are developing fast. However, the rare Indium and Tellurium limited the mass product and application. As a result, the new research work focus to the earth abundant photovoltaic materials in the thin film solar cell field. CuSbS2 is one of candidate materials as absorption layers. However, the recorded efficiency of CuSbS2 solar cell is only 3.1%, which is far below its theory efficiency 23%. The reasons of low efficiency are not clear till now. The related studies of physics mechanism become more and more necessary and important. In this program, we will employ the first-principles to calculate the forming energies of several phases in the films, the forming energies of the defects in the grain bulks and boundaries, and the energy levels of those defects. Furthermore, we are planning to investigate the phases and defects of CuSbS2 films by using X-ray Diffraction, Raman spectrum, X-ray photoelectron spectroscopy and transmission electronic microscopy. And we are also going to analyze the electrical properties of thin films with Hall effect measurement, Time-resolution PL spectrum, photon-conductivity and temperature-dependant resistance measurements. Finally, those theoretical and experimental studies will contribute to the explanations of physical mechanism of carrier transportation in the CuSbS2 films. This work will be benefit to the research and fabrication of high efficiency CuSbS2 solar cells.

由于能源短缺和环境污染等问题，近年来各国积极发展包括太阳能在内的各种可再生能源。其中，薄膜化合物太阳能电池发展非常迅速，如碲化镉和铜铟镓硒电池。但碲和铟的稀缺性限制了其大规模应用，发展高丰度光伏材料成为一个重要研究方向，而铜锑硫是其中较为合适的吸收层材料之一。目前报道的铜锑硫光伏电池的最高转换效率仅有3.1%，离它的理论效率23%还有相当大的差距，限制铜锑硫电池效率的机制还不是非常清楚。本项目利用第一性原理计算和X射线衍射、拉曼光谱、X射线光电子谱、透射电镜等实验手段，研究铜锑硫内部几种多元相的热力学稳定性、晶粒和晶界处缺陷类型、分布、形成能和占据的能级位置等；通过霍尔测试、时间分辨PL谱、光电导和温度-电阻测量等，获得材料电学输运性能。理论结合实验，研究这些相与缺陷对载流子输运过程造成的影响，揭示铜锑硫材料中限制载流子输运的物理机制问题，为制备高效光伏电池提供坚实的基础。

由于能源短缺和环境污染等问题，近年来各国积极发展包括太阳能在内的各种可再生能源。其中，薄膜化合物太阳能电池发展非常迅速，例如碲化镉和铜铟镓硒电池。但是，碲和铟的稀缺性限制了其大规模应用，因此发展新型光伏材料是一个重要研究方向。本项目中，我们从铜铋硫薄膜材料的合成入手，发展了一套铜铋硫薄膜的制备方法，利用X射线衍射、拉曼光谱、X射线光电子谱、透射电镜等手段研究分析铜铋硫体内多元相的分布、缺陷结构和密度等；利用第一性原理计算，研究铜铋硫和铜铋硒内部几种多元相的热力学稳定性、晶粒和晶界处缺陷形成能和占据的能级位置等。理论结合实验，研究这些相与缺陷对载流子输运过程造成的影响，并在此基础上制备了铜铋硫薄膜光伏电池。进一步，我们对其做硒化处理，制备了铜铋硒薄膜，并发现，通过控制硒化过程中氧气的含量，可以制备出片层结构的铜铋硒氧薄膜，并基于此薄膜发展了近红外光电探测器和光催化器件等。我们的研究为铜铋系列薄膜在光伏、光电和光催化方面的应用奠定了基础。在此项目支持下，我们共发表SCI论文4篇，获得国家发明专利授权1项，出版相关专著1本，在国际会议上做口头报告1次，培养毕业硕士生1名，合作培养在读博士生2名。