Adsorption of Dye Molecules on Single Crystalline Semiconductor Surfaces: An Electrochemical Shell-Isolated Nanoparticle Enhanced Raman Spectroscopy Study

作者：Xie, Li-Qiang; Ding, Ding; Zhang, Meng; Chen, Shu; Qiu, Zhi; Yan, Jia-Wei; Yang, Zhi-Lin; Chen, Ming-Shu^*; Mao, Bing-Wei^*; Tian, Zhong-Qun

来源：Journal of Physical Chemistry C, 2016, 120(39): 22500-22507.

DOI：10.1021/acs.jpcc.6b07763

• SENSITIZED SOLAR-CELL
• (2,2'-BIPYRIDYL-4,4'-DICARBOXYLIC ACID)RUTHENIUM(II) COMPLEXES
• CHARGE-TRANSFER
• TIO2 NANOPARTICLES
• N719 DYE
• SCATTERING
• EFFICIENCY
• RUTILE
• ABSORPTION
• INTERFACE

Adsorption of dye molecules on semiconductor surfaces dictates the interaction at and thus the electron transfer across the interface, which is a crucial issue in dyesensitized solar cells (DSSCs). However, despite that surface enhanced Raman spectroscopy (SERS) has-been employed to study the interface, information obtained so far is gathered from surfaces of irregularly arranged nanoparticles, which places complexities for precise attribution of adsorption configuration of dye molecules. Herein, we employ single crystalline rutile TiO2(110) for Raman spectroscopic investigation of TiO2 dye interfaces under electrochemical control by utilizing the enhancement of Au@SiO2, core shell nanoparticles. FD-TD simulation is performed to evaluate the localized electromagnetic field (EM) created by the core shell nanoparticles while Mott-Schottky measurements are used to determine the band structure of the semiconductor electrode. Comparative investigations are carried out on nanoporous P25 TiO2 electrodes. The potential-dependent Raman shift of v(N=C=S) suggests that the binding of the SCN group of N719 to the TiO2 surface is the intrinsic nature of the TiO2-N719 interaction, after removing the possible bonding complexity by surface roughness. Nevertheless, hydrogen bonding between COOH and the TiO2 appears to be more favorable on the atomic flat rutile TiO2(110) surface than on the surface of nanoporous P25 nanoparticle as revealed by the stronger Raman shift of v(C=O) (COOH) on the former. Electrochemical SERS (EC-SERS) results show that photoinduced charge transfer (PICT) occurs for both the P25 and rutile(110) TiO2 surfaces, and the potential to achieve PICT resonance depends on the band structure of the semiconductor. Our work demonstrates that EC-SERS can be applied to study the single crystalline semiconductor molecule interfaces using core shell based surface plasmonic resonance (SPR) enhancement strategy, which would promote fundamental investigations on interfaces of photovoltaic and photocatalytic systems.

• 出版日期2016-10-6
• 单位厦门大学