Abstract
The current study presents a new type of inexpensive and very sensitive bulk heterojunction (BHJ) organic photo- sensor (OPS) configuration that incorporates a layer of liquid electrolyte into the conventional BHJ photodiode arrangement. Initially, a P3HT: PCBM blend based photo-anode was deposited onto ITO substrates using spin coating. Then the semiconductor coated photo-anode was attached to a Pt/ITO counter electrode. A 40 mm gap between photo-anode and counter electrode was filled with a liquid (iodine based) HI-30 electrolyte. Various electrical parameters including ideality factor, series and shunt resistance were extracted from the current-voltage characteristics under dark and light conditions. The value of mobility measured under dark conditions was found to be 25.58 x 10(-6) m(2) V-1 s(-1). In addition, the samples were found to have a series and shunt resistance of 133.33 Omega and 74.70 k Omega, respectively. Under illumination, the fabricated photodiodes exhibited a linear current-irradiance relationship, with a rapid response time, when exposed to transient light, thus making the newly proposed hybrid BHJ photo- diode configuration a potential alternative to the conventional photo-sensors.