First principles study of ruthenium(ii) sensitizer adsorption on anatase TiO2 (001) surfaceElectronic supplementary information (ESI) available. See DOI: 10.1039/c5ra06743j

• Main Authors: Yang, Hao, Li, Jia, Zhou, Gang, Chiang, Sum Wai, Du, Hongda, Gan, Lin, Xu, Chengjun, Kang, Feiyu, Duan, Wenhui
• Format: Article
• Language: English
• ISSN: 2046-2069
• DOI: 10.1039/c5ra06743j

We present a systematic investigation of the adsorption behavior of the highly efficient ruthenium( ii ) sensitizer (N3) on the anatase TiO 2 (001) surface based on density functional theory. Three preferable configurations can be formed by exploiting two or three carboxylic groups attached to the TiO 2 surface, with their adsorption energies differing slightly. The interplay of N3 with the (001) surface is considerably stronger than that of N3 with the (101) surface, resulting in a larger dye coverage on the (001) surface. The energy gap of the N3 sensitizer, determining the absorption spectrum, decreases about 0.12 eV upon adsorption, suggesting an even larger range for the absorption spectrum than for the isolated N3 molecule. Moreover, the higher conduction band minimum of the TiO 2 (001) surface with N3 adsorption, compared with that of the (101) surface, indicates the higher open circuit potential. These results provide a clue to understand the high solar light-to-electricity conversion efficiency of dye sensitized solar cells with TiO 2 nanocrystals exposing a high percentage of {001} faces. We compared the photoelectrical performance of sensitized TiO 2 (001) and (101) surfaces exposed in the photoanode of dye sensitized solar cells based on first-principles calculation.