Fabrication and performance studies of TiOz and Porphyrin Heterojunction based organic photodetector

Organic photodetector of TiOz/Porphyrin has been fabricated and its performance has been tested in dark and under vaiious illumination of light intensityfrom 20 to 100 mWcm-'. Foursamples of porphyrin films have been used in the device, namely 1, 3, 5 and 7 times spin coating. TiOz films were deposited onto ITO covered glass substrate by controlled hydrolysis technique assisted with spin coating technique. Then porphyrin film was deposited on TiOz using spin coating technique. The films of TiOz/porphyrin has absorbance maximum at 660 nm, which is in the red region. An aluminium electrode was prepared on top of porphyrin films by electron beam evaporation technique. The device shows rectification behaviour in the dark and shows photosensitization effect under illumination of visible lights. The device with 3 times spin coating of porphyrin shows the highest J"" of 1.02 pAcm'2 and Vo" of 520 mV. (Received November 2, 2009; accepted November 12,2009) Keyv,ords : Photodetector, Photosensitizing, Porphyrin, Ti0