Citation:
Abstract:
We present a strategy for the synthesis of a well-defined rod-coil block copolymers of regioregular poly(3hexylthiophene) and polystyrene (P3HT-b-PS), carrying pendant fullerenes (C60) at precise positions along the PS block. The synthesis is achieved by combining ‘living’ anionic polymerization, Kumada catalyst-transfer polycondensation, and click chemistry. Azide terminated polystyrene was synthesized via anionic polymerization, while C60 moieties were grafted along the coil block with a [4+2] Diels-Alder cycloaddition reaction. The regioregular poly(3-hexylthiophene) rod donor block was end-capped with alkyne and was coupled with the azide terminated polystyrene via a copper catalyzed alkyne-azide cycloaddition. Size exclusion chromatography (SEC), NMR, and FTIR spectroscopies were employed to confirm the synthesis of the diblock copolymers. Furthermore, the end-capping of the ‘living’ polystyrene (PS) with the diphenylethylene cyclobutene (DPE-CB) end-group was confirmed by matrixassisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS). Thermogravimetric analysis (TGA) was employed for the estimation of the C60 content in the block copolymer. The C60 content at the coil block was 22 wt% and a strong quenching of photoluminescence (PL) was observed as the result of the aggregation and percolation structure of the C60 within the PS phase. This behavior indicates that the bonding of C60 across the PS block may offer new routes to engineering stable morphologies, where the degree of aggregation/crystallization of the acceptor material is of paramount importance for stable and efficient electron transport.