Photovoltaic effect in titanium dioxide/polythiophene cell

The photovoltaic effect has been observed in a titanium dioxide (TiO2) and polythiophene (PT) composite cell, ITO/TiO2/PT/Au. The TiO2/PT junction forms a rectifying contact and the ideality is better than that of the TiO2/ZnPc junction reported previously. There exists a good correlation between the optical absorption spectrum of the PT layer. and collection efficiency of the cell with illumination from the ITO side. This indicates that the TiO2 layer effectively works as a wide-gap window material. Photovoltaic and electrical properties of the cell are varied considerably by changing the undoping potential of the PT layer. These phenomena are interpreted in terms of the band theory taking into consideration the contribution from surface states.