物理化学学报 >> 2016, Vol. 32 >> Issue (4): 983-989.doi: 10.3866/PKU.WHXB201603144

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CdS/CdSe/TiO2多级空心微球光阳极中量子点覆盖度的提高

王丽娟1,2,李琦2,郝彦忠3,申世刚1,*(),徐东升2,*()   

  1. 1 河北大学化学与环境科学学院, 河北保定 071002
    2 北京大学化学与分子工程学院, 北京分子科学国家实验室, 北京 100871
    3 河北科技大学理学院, 石家庄 050018
  • 收稿日期:2016-02-26 发布日期:2016-04-07
  • 通讯作者: 申世刚,徐东升 E-mail:shensg@hbu.edu.cn;dsxu@pku.edu.cn
  • 基金资助:
    国家自然科学基金(21133001, 21303004);国家重点基础研究发展规划项目(973)(2013CB932601, 2014CB239303);河北省自然科学基金(B2014208062)

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)

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摘要：

TiO2多级空心微球(THHSs)具有高的比表面积、强的光散射效应以及良好的电子传输性质,以此作为光阳极材料,可以显著提升CdS/CdSe敏化太阳能电池(QDSSCs)的性能。但基于化学浴沉积方法获得的这一类电池中量子点在光阳极表面的覆盖度通常不高(50%左右),本文发展了一种基于表面选择性吸附原理的多步沉积方法,选取特定分子(正十二硫醇)限制已有量子点的生长,通过二次沉积成功提高了CdS/CdSe在TiO2多级空壳微球表面的覆盖度。使用此方法最终得到高达85.4%的覆盖度。结果表明,量子点覆盖度的增加有效提高了电池对太阳光的利用率,使得光电流获得了明显的增加。同时,二氧化钛空白表面积的减小还可以抑制电子和空穴的复合。优化后的电池光电流密度为15.69 mA·cm-2,填充因子为0.583,电压为0.605 V,最高光电转换效率为5.30%。

关键词: 表面覆盖度, 二次沉积, CdS/CdSe量子点, 太阳能电池

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