Semiconducting end-perfluorinated P3HT–fullerenic hybrids as potential additives for P3HT/IC70BA blends

Abstract

An efficient route to synthesise hybrid polymers consisting of a semiconducting polymer and a fullerene unit, for BHJ OPV devices is presented herein. The synthetic procedure is based on the in situ functionalisation of regioregular polythiophenes of various molecular weights with perfluorophenyl moieties at the ω end position of the polymeric chains, after the GRIM polymerisation reaction. Each of the perfluorophenyl moieties is then decorated with an azide group, and employed in a [3 + 2] cycloaddition reaction with fullerene species, i.e. C₇₀ or IC₇₀MA, yielding P3HT–fullerene hybrids covalently linked via aziridine bridges. The effectiveness of the purification procedures of the above organic and hybrid materials were evaluated by extended spectroscopic and chromatographic methods. The optical and electrochemical characterisation of the resulting hybrid structures revealed that the unique optoelectronic properties of the P3HT polymers are retained in the hybrid materials. Whereas the morphological properties are largely affected by the introduction of the C₇₀ and IC₇₀MA fullerenes. The enhanced and tunable nanophase separation observed in the polymer–fullerene hybrid films coupled with their excellent optoelectronic properties makes them exciting potential polymeric additives for the P3HT:IC₇₀BA active blends.