Optical and photosensing properties of gold nanoparticles doped poly (3-hexylthiophene-2, 5-diyl) thin films

Photosensing of ITO/PEDOT: PSS/P3HT: Au NPs (170nm)/Al devices for different concentrations of gold nano particles (Au NPs). [Display omitted] •Effect of gold nanoparticles doping on the optical and photosensitivity of P3HT was studied.•Absorption enhanced for AuNPs doped P3HT thin films.•Narrowing of band gap from 2.1 eV to 1.75 eV on doping of P3HT thin films.•Enhanced Photosensing device performance of doped P3HT thin films. Optical and photosensing properties of gold nanoparticles (AuNPs) doped Poly (3-hexylthiophene-2, 5-diyl) (P3HT) thin films, with varying concentrations of AuNPs, were studied. On doping, absorption increased and the band gap reduced from 2.1 eV (pristine P3HT) to 1.75 eV (P3HT: AuNPs (0.1%)) and this device exhibited a superior performance with a responsivity of 35.65 µA/W and a photoresponse as high as 571, compared to the other dopant concentrations. No perceptible change was observed in the device performance for too low concentrations of AuNPs (0.075% and below) and the performance deteriorated for higher concentrations of AuNPs (0.2% and above) in P3HT thin films.