量子点敏化太阳能电池的结构优化及性能分析  

Structural optimization and performance analysis of quantum-dots-sensitized solar cells

作　　者：宋孝辉[1] 汪敏强[1] 邓建平[1] 杨智[1] 

机构地区：[1]西安交通大学国际电介质研究中心,电子陶瓷与器件教育部重点实验室,西安710049

出　　处：《科学通报》2013年第30期3052-3061,共10页Chinese Science Bulletin

基　　金：国家自然科学基金(61176056;91123019)资助

摘　　要：目前,液态量子点敏化太阳能电池的转换效率虽然已达到6.5%,但距其理论最高转换效率44%还有很大的差距,因此还需要对电池结构和材料工艺进一步优化来提高其光电转换性能.本文通过溶胶-凝胶法在FTO导电玻璃基底与多孔TiO2纳米晶电极之间制备了一层致密的TiO2薄膜,以此作为阻挡层来阻止FTO与电解液的直接接触,抑制传输到FTO中的光生电子与多硫电解液中Sx2离子的复合.分别采用X射线衍射(XRD)、场发射扫描电子显微镜(FESEM),原子力显微镜(AFM)和紫外-可见吸收光谱(UV-vis)对TiO2阻挡层薄膜的结构、形貌和光学特性进行了表征.结果表明:该薄膜主要呈锐钛矿结构,表面平整致密,在可见光波段透过率良好.通过对有/无TiO2阻挡层的电池性能对比发现,阻挡层的引入使电池的短路电流、开路电压和光电转换效率分别提高了47.2%,4.2%和34.8%.同时,本文研究了阻挡层厚度对电池光电性能的影响,发现随着厚度的增加电池的转换效率下降,这是由于TiO2阻挡层厚度的增加导致光阳极透过率降低;同时TiO2阻挡层本身的电阻增大,影响了多孔TiO2电极与FTO基底之间的电子传输.At present, the photoelectric conversion efficiency of the liquid junction quantum dot-sensitized solar cells （QDSSC） has reached 6.5%, but this value is still far from the theoretical maximum efficiency of 44%. Therefore, further optimization of the cell structure and fabrication technology are required to enhance solar cell performance. In this paper, a compact TiO2 thin film, prepared by a sol-gel method, is introduced between the FTO conducting substrate and the mesoporous TiO2 electrode. This compact TiO2 film is used as a barrier layer to prevent the direct contact between FTO substrate and electrolyte, and therefore suppress the back electron transfer from FTO to electrolyte. The structure, surface morphology, and optical properties of this compact TiO2 film are characterized by XRD, SEM, AFM, and UV-vis spectrum. The results show that this TiO2 film with smooth surface is mainly an anatase structure, and it has good light transmission in visible light region. Compared with the QDSSC without this compact TiOz layer, the short-circuit current density, open-circuit voltage, and solar energy conversion efficiency of the QDSSC with the compact layer are improved by 47.2%, 4.2% and 34.8%, respectively. Meanwhile, the influence of the thickness of TiO2 barrier layer on photoelectric properties of QDSSC is investigated, and we find that the efficiency of the cell is decreased while increasing the thickness of barrier layer. That can be attributed to that the increase of the thickness can reduce the transmittance of photoanode, and the resistance of TiO2 barrier layer will also increase, which may adversely influence the electron transportation between the mesoporous TiO2 electrode and FTO substrate.

关 键 词：量子点敏化 太阳能电池 阻挡层 溶胶-凝胶 TIO2薄膜 复合电流 

分 类 号：TM914.4[电气工程—电力电子与电力传动]