Enhancing the Performance of Organic Phototransistors Based on Oriented Floating Films of P3HT Assisted by Al-Island Deposition.

The fabrication of high-performance Organic Phototransistors (OPTs) by depositing Al-islands atop Poly(3-hexylthiophene) (P3HT) thin film coated using the unidirectional floating-film transfer method (UFTM) has been realized. Further, the effect of Al-island thickness on the OPTs' performance has been intensively investigated using X-ray photoelectron spectroscopy, X-ray Diffraction, Atomic force microscopy and UV-Vis spectroscopy analysis. Under the optimized conditions, OPTs' mobility and on-off ratio were found to be 2 × 10 -2 cm 2 V -1 s -1 and 3 × 10 4 , respectively. Further, the device exhibited high photosensitivity of 10 5 , responsivity of 339 A/W, detectivity of 3 × 10 14 Jones, and external quantum efficiency of 7.8 × 10 3 % when illuminated with a 525 nm LED laser (0.3 mW/cm 2 ).