Highly Sensitive Organic Phototransistors Fabricated from PCPDTBT:PCBM Blend

Abstract Organic phototransistors (OPTs) play a crucial role in various light sensing and imaging applications. In this work, we have fabricated highly sensitive Poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b’]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT)/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blended thin film based OPTs using ribbon-floating film transfer method. A high charge carrier mobility (μ) of 0.002 cm 2 V −1 s −1 and an I on /I off of 6 × 10 4 was showcased by the blended polymer thin film based OPT as compared to its pristine polymer thin film based counterpart which had a μ of 0.001 cm 2 V − 1 s −1 and an I on /I off of 9 × 10 3 . Further, the blended polymer thin film based OPT demonstrated a high photosensitivity of 6.6 × 10 3 and a photoresponsivity of 0.13 A/W towards white light which were much superior than those of many of the previously reported polymer thin film based OPTs. The results hold crucial significance towards the development of cost effective blended polymer thin film based OPTs.