Here, we report a novel method to synthesize multifunctional nanoparticles that can be used in biological studies, such as in cell imaging and as a carrier for biomolecules/drugs. The nanoparticles were prepared either via Cu-catalyzed or cucurbit[6]uril (CB6)-catalyzed click reactions between azide groups containing hydrophobic blue, green and yellow emitting fluorene-based conjugated polymers and a hydrophilic diaminodialkyne containing cross-linker. Through the click reaction, not only does the cross-linking confer stability, but it also introduces functional groups, such as triazoles and amines, to the nanoparticles. Moreover, CB6 not only acted as a catalyst to facilitate the copper-free click reaction, but it also allowed us to obtain nanoparticles containing rotaxanes in which the triazole units were encapsulated by CB6 units. TEM images of the nanoparticles also showed that they display very interesting morphologies. Incorporation of hydrophilic functional groups to the hydrophobic conjugated polymers resulted in a distinct phase separation, producing Janus-like or patchy particles. © 2011 The Royal Society of Chemistry

Alkyl solubilizing side chains on conjugated polymers can serve as a handle for modifying polymer properties. Recently, oligo-ether and semifluoro alkyl side chains were utilized to tune the surface energy of random P3HT-based polymers without changing the optical and electronic properties. Here, this method is applied to semirandom poly(3-hexylthiophene-thiophene-diketopyrrolopyrrole) (P3HTT-DPP) and the subsequent polymer device, optical, electronic, structural, and thermal properties are characterized. P3HTMETT-DPP, bearing oligo-ether side chains, exhibited higher crystallinity, closer lamellar packing, and lower temperature thermal transitions. P3HTFHTT-DPP, featuring semifluoro alkyl side chains, presented reduced crystallinity, greater lamellar packing distances, and higher temperature thermal transitions. P3HTMETT-DPP performed similarly to P3HTT-DPP under identical processing conditions, whereas P3HTFHTT-DPP had greatly reduced J SC due to lower polymer concentration necessitated by solubility.

Semi-random conjugated polymers based on 3-hexylthiophene have been extensively investigated within the past several years as an effective route to broadening absorption without losing desirable properties of poly­(3-hexyl­thiophene) (P3HT). Here, we closely investigate the structural, optical, and electronic differences found in randomized analogues of poly­(3-hexylthiophene–thiophene–2,3-dimethylthieno­[3,4-b]­pyrazine) (P3HTT-TP) semi-random polymers. Proton nuclear Overhauser effect spectroscopy is used to identify linkages within the conjugated backbone, and UV–vis, cyclic voltammetry, and grazing incidence X-ray diffraction are used to determine the influence of the subtle differences in monomer connectivities. Semi-random P3HTT-TP was found to have a stronger intramolecular charge transfer absorption band and higher thermal transitions compared to its randomized analogue. Additionally, the function of the thiophene unit in the semi-random polymers is observed and demonstrated to have key electronic effects as well as maintaining a higher HOMO level, aside from providing needed stoichiometric balance to the acceptor monomer. This work demonstrates the utility of the semi-random polymer approach as a robust tool for incorporating small amount of electron-poor monomers for the purpose of improving the absorption breadth of P3HT-based polymers.

P3HT-based copolymers are synthesized via direct arylation polymerization (DArP) in order to evaluate potential defects and the resulting influence on OPV performance.