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Nanoparticle/Dye Interface Optimization in Dye‐Sensitized Solar Cells
Author(s) -
Bazzan Giorgio,
Deneault James R.,
Kang TaeSik,
Taylor Barney E.,
Durstock Michael F.
Publication year - 2011
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201100595
Subject(s) - materials science , dye sensitized solar cell , adsorption , desorption , mesoporous material , monolayer , chemical engineering , dielectric spectroscopy , raman spectroscopy , titanium dioxide , photochemistry , ruthenium , energy conversion efficiency , molecule , electrolyte , nanotechnology , electrochemistry , electrode , optoelectronics , catalysis , organic chemistry , optics , chemistry , composite material , physics , engineering
A critical component in the development of highly efficient dye‐sensitized solar cells is the interface between the ruthenium bipyridyl complex dye and the surface of the mesoporous titanium dioxide film. In spite of many studies aimed at examining the detailed anchoring mechanism of the dye on the titania surface, there is as yet no commonly accepted understanding. Furthermore, it is generally believed that a single monolayer of strongly attached molecules is required in order to maximize the efficiency of electron injection into the semiconductor. In this study, the amount of adsorbed dye on the mesoporous film is maximised, which in turn increases the light absorption and decreases carrier recombination, resulting in improved device performance. A process that increases the surface concentration of the dye molecules adsorbed on the TiO 2 surface by up to 20% is developed. This process is based on partial desorption of the dye after the initial adsorption, followed by readsorption. This desorption/adsorption cycling process can be repeated multiple times and yields a continual increase in dye uptake, up to a saturation limit. The effect on device performance is directly related and a 23% increase in power conversion efficiency is observed. Surface enhanced Raman spectroscopy, infrared spectroscopy, and electrochemical impedance analysis were used to elucidate the fundamental mechanisms behind this observation.