Ferroelectric liquid-crystalline semiconductors based on a phenylterthiophene skeleton: effect of the introduction of oligosiloxane moieties and photovoltaic effect

Ferroelectric liquid-crystalline phenylterthiophene derivatives bearing a decenyl group, disiloxane chain, and cyclotetrasiloxane ring were synthesized. These compounds exhibited a chiral smectic C (SmC*) phase. The spontaneous polarizations of the compounds exceeded 50 nC cm(-2). The hole mobilities determined by the time-of-flight method were in the order of 1 x 10(-4) cm(2) V-1 s(-1). The compound with a decenyl group exhibited an anomalous photovoltaic effect in the SmC* phase although the conversion efficiency was lower than 0.01%. Notably, even the compound bearing a bulky cyclotetrasiloxane ring exhibited an enantiotropic SmC* phase.