Photochemistry and photophysics of organomonosilane and oligosilanes: Updating their studies on conformation and intramolecular interactions

This review article deals with recent studies on photochemistry and photophysics of organosilicon monomer to oligomers (here, chain length of Si is mostly less than 10). Arylmonosilanes have been caught attention as the fluorescent and charge-transporting materials. Increasing in silicon chain length, an importance of conformation for silicon single chain in organooligosilane is significant. The conformation affects the spectroscopic, photochemical, and photophysical characteristics. This review is mainly focused on the properties of arylsilanes and α,ω-diaryloligosilanes in which three types of intramolecular interactions, the σ–σ interaction between silicon atoms in a chain unit, the π–π interaction between two aromatic groups, and the σ–π interaction between an aromatic group and a silicon chain unit are expected. As a result, intramolecular excimer/exciplex formation, charge-transfer (CT) complex formation, excitation energy or photoinduced electron transfers were observed by the steady-state and the time-resolved fluorescence (TR-FL) spectroscopy. For the better understanding, the recent conformational studies of single oligosilane chain are also reviewed.