物理化学学报 >> 2012, Vol. 28 >> Issue (11): 2632-2640.doi: 10.3866/PKU.WHXB201207301

电化学和新能源 上一篇    下一篇

表面In掺杂TiO2的N719/TiO2-Inx%/FTO薄膜电极的光电转换效率

程辉1,2, 姚江宏1,2, 曹亚安1,2   

  1. 1. 南开大学物理科学学院, 天津 300071;
    2. 南开大学泰达应用物理学院, 弱光非线性光子学教育部重点实验室, 天津 300457
  • 收稿日期:2012-06-07 修回日期:2012-07-23 发布日期:2012-10-17
  • 通讯作者: 曹亚安 E-mail:caoyaan@yahoo.com
  • 基金资助:

    国家自然科学基金(50872056, 51072082, 21173121)资助项目

Photoelectric Conversion Efficiency of N719/TiO2-Inx%/FTO Film Electrodes Incorporating In Doped at the TiO2 Surface

CHENG Hui1,2, YAO Jiang-Hong1,2, CAO Ya-An1,2   

  1. 1. College of Physics, Nankai University, Tianjin 300071, P. R. China;
    2. The Key Laboratory of Weak Light Nonlinear Photonics, Ministry of Education, Teda Applied Physics School, Nankai University, Tianjin 300457, P. R. China
  • Received:2012-06-07 Revised:2012-07-23 Published:2012-10-17
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (50872056, 51072082, 21173121).

摘要:

采用溶胶-凝胶法制备出In 表面修饰的TiO2 (TiO2-Inx%)纳米粒子, x%代表在In 掺杂的TiO2样品中In3+与In3+和Ti4+离子摩尔百分含量. 利用二(四丁基铵)顺式-双(异硫氰基)双(2,2'-联吡啶-4,4'-二羧酸)钌(II)(N719)作为敏化剂, 制备出N719/TiO2/FTO (氟掺杂锡氧化物)和N719/TiO2-Inx%/FTO染料敏化薄膜电极. 光电转换效率实验表明, 在薄膜电极+0.5 mol·L-1 LiI+0.05 mol·L-1 I2的三甲氧基丙腈(MPN)溶液+Pt 光电池体系中,N719/TiO2-Inx%/FTO薄膜电极的光电转换效率均高于N719/TiO2/FTO, 其中N719/TiO2-In0.1%/FTO的光电转换效率比N719/TiO2/FTO提高了20%. 利用X 射线衍射(XRD)、X 射线光电子能谱(XPS)、漫反射吸收光谱(DRS)、荧光(PL)光谱和表面光电流作用谱确定了TiO2-Inx%样品中In3+离子的存在方式和能带结构; 利用表面光电流作用谱研究了N719/TiO2-Inx%/FTO薄膜电极的光致界面电荷转移过程. 结果表明, In3+离子在TiO2表面形成O-In-Cln (n=1, 2)物种, 该物种的表面态能级位于导带下0.3 eV处; 在光电流产生过程中, O-In-Cln (n=1, 2)表面态能级有效地抑制了光生载流子在TiO2-Inx%层的复合, 促进了阳极光电流的增加, 从而导致N719/TiO2-Inx%/FTO薄膜电极的光电转化效率高于N719/TiO2/FTO, 并进一步讨论了光致界面电荷转移的机理.

关键词: TiO2-Inx%, O-In-Cln (n=1, 2)物种, 表面敏化, N719/TiO2-Inx%/FTO, 光电转换效率

Abstract:

Nanoparticles of TiO2 with surface modification by In doping were prepared using a sol-gel technique. These materials had the general formula TiO2-Inx%, where x represents the mole percent of In3+ ions in the combined In3+ and Ti4+ metal ion content. N719/TiO2/FTO (fluorine doped tin oxide) and N719/ TiO2-Inx%/FTO film electrodes were prepared, using N719 dye as a sensitizing agent. These thin film electrodes were incorporated into solar cells composed of 0.5 mol·L-1 LiI, 0.05 mol·L-1 I2, methoxypropionitrile (MPN) and Pt. It was determined that the photoelectric conversion efficiencies of the N719/TiO2-Inx%/FTO film electrodes were higher than that of N719/TiO2/FTO. In particular, the conversion efficiency of N719/TiO2-In0.1%/FTO was 20% greater than that of N719/TiO2/FTO. The band structure and In3+ ion content of TiO2-Inx% samples were analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and optical diffuse-reflection spectroscopy (DRS), as well as by examination of photoluminescence (PL) and surface photocurrent action spectra. The photo-induced charge transfer processes of the N719/TiO2-Inx%/FTO film electrodes were also elucidated using surface photocurrent action spectra. The results showed that O-In-Cln (where n=1 or 2) species were formed at the TiO2 surface, with surface state energy levels 0.3 eV below the conduction band of TiO2. The surface state energy levels of these species effectively inhibit the recombination of photo-generated carriers during the photocurrent generation process, and also serve to increase the anodic photocurrent and significantly improve the photoelectric conversion efficiency of N719/TiO2-Inx%/FTO thin film electrodes. This work also discusses the interfacial light-induced charge transfer mechanisms in these materials.

Key words: TiO2-Inx%, O-In-Cln (n=1, 2) species, Surface-sensitization, N719/TiO2-Inx%/FTO, Photoelectric conversion efficiency

MSC2000: 

  • O646