Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (4): 983-989.doi: 10.3866/PKU.WHXB201603144

• ARTICLE • Previous Articles     Next Articles

Improvement of Quantum Dot Coverage of CdS/CdSe/TiO2 Hierarchical Hollow Sphere Photoanodes

Li-Juan WANG1,2,Qi LI2,Yan-Zhong HAO3,Shi-Gang SHEN1,*(),Dong-Sheng XU2,*()   

  1. 1 College of Chemistry and Environmental Science, Hebei University, Baoding 071002, Hebei Province, P. R. China
    2 Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China
    3 College of Science, Hebei University of Science and Technology, Shijiazhuang 050018, P. R. China
  • Received:2016-02-26 Published:2016-04-07
  • Contact: Shi-Gang SHEN,Dong-Sheng XU E-mail:shensg@hbu.edu.cn;dsxu@pku.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21133001, 21303004);National Key Basic Research Program of China (973)(2013CB932601, 2014CB239303);Natural Science Foundation of Hebei Province, China(B2014208062)

Abstract:

TiO2 hierarchical hollow spheres (THHSs) are considered an ideal material for photoanodes of CdS/CdSe quantum dot-sensitized solar cells (QDSSCs) because of their high specific surface area, strong light scattering effect, and excellent charge transfer capability. However, in a typical CdS/CdSe quantum dot deposition process, chemical bath deposition, the coverage of the CdS/CdSe quantum dots is relatively low (~50%). According to the different surface properties of CdS/CdSe quantum dots and TiO2, we have developed a novel route to increase the quantum dot coverage while preventing their aggregation. In our method, 1-dodecanethiol was used as a surface protection molecule on the quantum dots. Then, in the secondary chemical bath deposition process, the newly emerged quantum dots grew only on the TiO2 surface and thus the coverage notably increased. Eventually, the quantum dot coverage reached 85.4%. This method effectively enhanced light utilization and led to an increase in the photocurrent of the QDSSCs. The reduced blank surface of TiO2 also efficiently suppressed electron-hole recombination. Thus, the photocurrent density was 15.69 mA·cm-2, the fill factor was 0.583, and the voltage was 0.605 V. As a result, a power conversion efficiency of 5.30% was obtained.

Key words: Surface coverage, Secondary deposition, CdS/CdSe quantum dot, Solar cell

MSC2000: 

  • O646