Hybrid nanocomposites of CdSe nanocrystals distributed in complexing thiophene-based copolymers

Abstract

Two types of conjugated polymers were prepared with the goal to blend them with rod-like CdSe nanocrystals. The polymers of the first type were synthesized through copolymerization of 3-octylthiophene and 3-methylene-ethylcarboxylate-thiophene to give polythiophene with solubilizing alkyl groups and methylene ester functional groups (PE series). Post-polymerization hydrolysis of the ester type polymers yielded acid-type ones (PA series). Photoluminescence (PL) quenching in these polymers induced by their titration with nanocrystals solution was chosen as a measure of the polymer-nanocrystal interactions. PL of polyacids turned out to be more efficiently quenched as compared to the case of polymers with ester groups which was interpreted as an indication of better electronic communication between the hybrid components. Infrared (IR) spectroscopy confirmed efficient coordination of the carboxylic groups to CdSe. Voltammetric studies combined with UV-vis spectroelectrochemistry enabled the determination of energy levels alignment of the molecular composite components which turned out to be of staggered type-appropriate for photovoltaic applications. The obtained blends of polyacids with CdSe nanocrystals, when studied by transmission electron microscopy (TEM), revealed the presence of an interpenetrating network in which nanorods were homogeneously distributed within the polymer matrix without any indication of agglomerates formation both on the film surface and in the cross-section. Blends with polymers containing ester groups were less homogeneous which could be explained by weaker polymer-nanocrystals interactions. Photovoltaic cells based on these hybrid materials are also discussed.

Donor–acceptor alternating copolymers containing thienopyrroledione electron accepting units: preparation, redox behaviour, and application to photovoltaic cells

“…The spectrum registered at E ¼ 0.95 V resembles those characteristic of partially doped conjugated polymers or spectra of polymers in which host-guest interactions impede the doping process. 22 From the point of view of the HOMO level determination the potential of the onset of the doping induced spectral changes is of crucial importance. In P1 these changes start to appear at E ¼ 0.48 V and up to E ¼ 0.70 V they are very pronounced.…”

Assemblies composed of oligothiophene–ruthenium complexes bound to CdSe nanoparticles

“…Although Ru dyes and CdSe nanoparticles have been studied individually and in connection with oligothiophenes [30][31][32][33][34][35], to the best of our knowledge there is no record of studying Ru dyes, oligothiophenes and CdSe in a single system. We have synthesized two new oligothiophenes, trithiophenes 2 and 5 ( Fig.…”

Fabrication and capacitive characteristics of conjugated polymer composite p-polyaniline/n-WO3 heterojunction

“…Polymer nanocomposites (PNCs) based on conjugated polymers (CPs) including polythiophene [1,2] polypyrrole (PPy) [3,4], poly(DNTD) [5,7], polyaniline (PANI) [8,9] and their derivatives have attracted huge attention. The methodology for combining CPs and inorganic materials has announced PANI because of its fascinating properties such as facile polymerization in aqueous media [10][11][12][13] or nonaqueous media [14], versatile redox behavior, good stability in air, low cost, high conductivity and high pseudocapacitance [15,16].…”