Molecular aggregation state and electrical properties of terthiophenes/imogolite nanohybrids

Abstract

Organic/inorganic nanohybrid materials composed of terthiophenes and imogolite were prepared by means of specific surface interaction between a phosphonic acid group in terthiophene derivatives and aluminol groups on the surface of imogolite. The new materials were investigated by FTIR, UVvis absorption, fluorescence spectroscopy, TEM observation, nitrogen adsorptiondesorption, and IV measurement. Addition of terthiophene of phosphonic acid derivatives into imogolite brought some changes in absorption and photoluminescence spectra, suggesting the formation of H-type aggregate on imogolite surface. The analysis of UVvis spectra and nitrogen adsorptiondesorption data provided insight into the effect of molecular structure of terthiophenes on the adsorption and aggregation behaviors on the imogolite surface. In addition, a significant enhanced current flow was observed through imogolite film when imogolite was chemisorbed by electron-withdrawing terthiophenes. In contrast, current flow decreased as the electron-donating terthiophene was chemisorbed on imogolite. A possible mechanism for such phenomena is discussed. © 2011 The Chemical Society of Japan.