Study of induced structural, optical and electrochemical properties of Poly(3-hexylthiophene) (P3HT), [6,6]-phenyl-C61-butyric-acid-methyl-ester (PCBM) and their blend as an effect of graphene doping

Abstract

Composites of graphene with Poly(3-hexylthiophene) (P3HT), [6,6]-phenyl-C61-butyric-acid-methyl-ester (PCBM) and their blends have been prepared via a facile chemical mixing approach. Graphene has been synthesized using a liquid phase chemical exfoliation method and characterized using imaging, electronic and spectroscopic techniques. Morphological analysis depicts the multi-layered structure of prepared graphene having approximately 9 layers, as estimated from Raman spectroscopy and AFM measurements. The value of energy gap between HOMO and LUMO of the prepared graphene has been determined using UV–Visible absorption spectroscopy and CV measurement, and found to be in close proximity. Further, UV–Visible and Raman spectroscopy suggest the formation of some localized trapping sites in between the band gap region of P3HT/PCBM and P3HT-PCBM blends as an effect of graphene doping leading to change in refractive index and bandgap values. Moreover, CV results also favour decrease in energy gap in composites after graphene loading Thus present study supports the well-dispersion and non-agglomeration of graphene within these polymers proper charge transfer between graphene layer and polymer chain. The sort of transfer of charge carriers from P3HT to graphene to PCBM is also conferring through the Raman measurements in blended films. Such interaction may help in designing of optoelectronic device with optimized photovoltaic performance.