Photoconduction of 9, 10-Anthraquinone Single Crystals

Bulky as well as needle-like single crystals of 9, 10-anthraquinone were grown by the Bridgman and the vapor phase growth technique respectively. The bulky single crystal is transparent and yellow and can be cleaved easily along (ab)-, (bc)- and (ac)-planes of the crystal. Crystals with dimension about 1×1×1 cm can be prepared easily. The DC-photoconductivity is about two orders of magnitude smaller than that of anthracene. It is recognized that carriers are generated with radiation at 4100 A which induces the n -π * transition of the molecule. Also carriers are generated for radiations which induce π-π * excitations in the wavelength region of 2500 A to 3000 A. In π-π * excitation region, the photocurrent with the illuminated electrode negative is much larger than that with the illuminated electrode positive. The photoconduction changes with thermal activation energy of 0.17 eV.