Organic phototransistor based on intramolecular charge transfer in a bifunctional spiro compound

We report on the fabrication of organic phototransistors based on the spiro-conjugated molecule 2,7-bis-(N,N'-diphenylamino)-2',7'-bis(biphenyl-4-yl)-9,9'-spirobifluorene. Intramolecular charge transfer leads to an increase in. charge carrier density, providing the amplification effect. The sensitivity is better than 1 A/W for ultraviolet light at 370, nm, making the device interesting for sensor applications. (C) 2004 American Institute-of Physics.