Fabrication and performance studies of TiO2 and Porphyrin Heterojunction based organic photodetector

Organic photodetector of TiO2/Porphyrin has been fabricated and its performance has been tested in dark and under various illumination of light intensity from 20 to 100 mWcm(-2). Four samples of porphyrin films have been used in the device, namely 1, 3, 5 and 7 times spin coating. TiO2 films were deposited onto ITO covered glass substrate by controlled hydrolysis technique assisted with spin coating technique. Then porphyrin film was deposited on TiO2 using spin coating technique. The films of TiO2/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(sc) of 1.02 mu Acm(-2) and V-oc of 520 mV.