Development of InP-based polymer nanocomposites by wet route for optoelectronic devices

Abstract

In this work, the effect of surface passivation of InP quantum dots (QDs) synthesized by the unconventional tri-n-octyl phosphine (TOP) route, on the structural and optoelectronic properties of their respective polymer nanocomposites, has been demonstrated by dispersing untreated and nascent hydrogen-treated InP QDs in P3HT polymer matrix, respectively. The surface passivation of InP QDs imparts photostability to its corresponding polymer–InP composite as a consequence of a better hydrogen passivation of defects acting as non-radiative recombination centres and can be achieved by employing a simple post-synthesis chemical treatment which is fast, reliable and reproducible. Here, with the distinctive usage of TOP both as a capping ligand and a source of phosphorus in conjunction with a novel chemical treatment, the quantum yield of InP QDs can be significantly enhanced and promotes charge transfer across donor (polymer)–acceptor (InP QDs) interface as supported by photoluminescence (PL) quenching studies as well. The increment in PL intensity upon incorporation of untreated InP QDs into the P3HT polymer matrix can be attributed to the dominance of Forster energy transfer between host P3HT polymer (donor) and guest InP nanocrystals (acceptors) in polymer/InP (untreated) composites. The mechanisms of energy and charge transfer in polymer–InP (u/t) based composites is depicted pictorally. The importance of these two different processes observed in polymer/InP (untreated) and polymer/InP (treated) composites is that it makes them useful for organic optoelectronic, i.e. electroluminescent and photovoltaic devices, respectively.