Nanofabrication of organic/inorganic hybrids of TiO2 with substituted phthalocyanine or polythiophene.

Organic photovoltaic cells, similar to Grätzel type, have been widely investigated in recent years. In the case of Grätzel-type cells, TiO2 colloids are usually spin-coated onto an electrode and then sintered. Later, such electrodes are immersed in dye solution to sensitize the TiO2 layer for fabrication of photovoltaic cells. In the current study, an attempt was made to fabricate photovoltaic cells using a layer-by-layer technique. Based on such a method, ordered substituted phthalocyanine or conducting polythiophene-sensitized TiO2 multilayers were fabricated at the molecular level. Buildup of multilayer films of copper phthalocyanine-capped TiO2 and poly(thiophene-3-acetic acid)/TiO2 was monitored by increments in the UV-visible absorption and the frequency decrease of quartz crystal microbalance. The ordered multilayers were further characterized by infrared spectroscopy, and electrochemical and photoelectrochemical measurements.