Anomalous photovoltaic effect based on spontaneous polarization of ferroelectric liquid crystals

合成了含十烯基、二硅氧烷链和四环硅氧烷环的铁电液晶（LC）苯基噻吩衍生物。这些化合物表现为手性近晶C （SmC*）相，其自发极化超过100 ncm -2。飞行时间法测定的孔迁移率约为1 × 10-4 cm2V-1s-1。具有十烯基的化合物在SmC*相中表现出反常的光伏效应。值得注意的是，即使是含体积较大的环四硅氧烷环的化合物也表现出嗜氧性SmC*相。带有十烯基链的化合物在SmC*相中表现出反常的光伏效应。在零偏置下，在光照前施加直流偏置，样品会产生反向的光电流。零偏压光电流的极性在照明前通过直流偏压的符号来改变。

Ferroelectric liquid-crystalline (LC) phenylterthiophene derivatives bearing a decenyl group, a disiloxane chain, and a tetracyclosiloxane ring has been synthesized. These compounds exhibit a chiral smectic C (SmC*) phase, where its spontaneous polarization exceeds 100 nCcm-2. The hole mobilities determined by a time-of-flight method were on the order of 1x10-4 cm2V-1s-1. The compound having decenyl group exhibits an anomalous photovoltaic effect in the SmC* phase. It should be noted that even the compound bearing a bulky cyclotetrasiloxane ring exhibit an enatiotropic SmC* phase. The compound bearing a decenyl chain exhibits anomalous photovoltaic effect in the SmC* phase. Under zer-bias, photocurrent in the reversed direction was generated when DC bias was aplied to the sample before light illumination. The polarity of the zero-bias photocurrent was changed by the sign of the DC bias before the illumination.