Photocurrent increase by doping a liquid crystal host with a functionalized fullerene

Doping a photoconductive mesogenic material with a small amount of functionalized fullerene significantly increases the photocurrent. LESR studies show the appearance of a long-lived charge-separated state under light illumination, with a negative charge on the fullerene moiety. This confirms that in the system studied the fullerene unit acts as an electron trap. In the lamellar structure of the liquid crystalline phase the fullerene units and mesogenic cores are separated, which ensures better space separation between negative and positive charges. As a result the charge recombination is slowed and the photocurrent is amplified.