PbS量子点薄膜作缓冲层的ZnO纳米杆与Cu2O薄膜异质结太阳电池

Based on the research of the ZnO nanorod growth, I-V characteristics of Cu2O and ZnO film heterojunction, preparation of semiconductor quantum dots, and theoretical computation on ZnO energy band structure, ZnO nanorod and Cu2O film n-i-p heterojunction solar cell using PbS quantum dot film as a buffer layer will be fabricated. ZnO nanorods will be grown on Al doped ZnO transparent conductive film. PbS quantum dot film will be prepared by chemical method. Cu2O film will be deposited by electrodeposition or magnetron sputtering. The transfer of photogenerated electrons between PbS quantum dot and ZnO nanorods will be theoretically studied. According to the theoretical results and I-V characteristics of solar cells, the effect of the size and crystalline quality of the PbS quantum dot film on efficiency of photogenerated carriers will be investigated. Adjusting the characterization of quantum dot, ZnO nanorod, and Cu2O film, the performance of heterojunction interface will be improved and the efficiency of the solar cell will be increased. The fabricated solar cells have high quality and its power conversion efficiency is expected to be higher than 5%, because PbS can absorb more solar energy and PbS buffer layer can improve the interfacial quality of the heterojunction. Our solar cells have the advantages of low cost, high stability, and long lifetime. It is very important for the advance of solar cell technology in our country.

在ZnO纳米杆、Cu2O与ZnO薄膜异质结、半导体纳米颗粒以及ZnO能带的计算等研究工作基础上，构建以窄带隙半导体量子点薄膜作缓冲层的ZnO纳米杆与Cu2O薄膜n-i-p型异质结太阳电池。首先利用热蒸发法在透明导电薄膜上生长ZnO纳米杆，接着在纳米杆上用化学溶液法制备PbS量子点薄膜，最后用电化学沉积或磁控溅射法制备Cu2O薄膜。结合第一性原理计算分析PbS量子点与ZnO纳米杆之间的光诱导电荷转移的微观机理，研究PbS量子点的大小和结晶性能对光生载流子产生效率的影响，通过对量子点、ZnO纳米杆和Cu2O薄膜特性的调控，改善异质结界面的性能，提高电池的转换效率。由于PbS可以增强电池对太阳光的吸收，且PbS薄膜缓冲层将改善异质结界面的特性；研制的电池将具有高的开路电压和大的短路电流，光电转换效率达5%，具有低成本、性能稳定和使用寿命长的优点，对提升我国太阳电池的技术水平有重要的实际意义。

氧化亚铜太阳能电池由于转换效率高、稳定性好、制备方法简单等优点，被认为是最有前景的一类太阳能电池。本项目以ZnO 纳米杆、Cu2O 与ZnO 薄膜异质结、半导体纳米颗粒等研究工作为基础，构建以窄带隙半导体量子点薄膜作缓冲层的ZnO 纳米杆与Cu2O 薄膜n-i-p 型异质结太阳电池。运用电化学沉积法，研究了氧化亚铜沉积电压、沉积时间和溶液pH值对电池性能的影响，发现沉积电压为1.0V、时间为120分钟、溶液pH>10时，可获得具有 (111)优先取向的氧化亚铜薄膜，并具有较好的光电转换效率。此外，通过热蒸发法制备的ZnO纳米杆（ZnO NWs）阵列，在其表面进一步通过化学溶液法沉积硫化铅量子点（PbS QDs），然后应用电化学法在其表面沉积Cu2O薄膜，初步构建了ZnO NWs/ PbS QDs/Cu2O异质结太阳能电池，发现ZnO纳米线经过PbS量子点修饰后开路电压提高了11%，但是电池性能有待进一步提高。这些结果对于构建高效太阳能电池，提高光电转换效率具有重要的指导意义。