Novel adamantane substituted polythiophenes as competitors to Poly(3-Hexylthiophene)

The investigation of poly(3-alkylthiophenes) (P3ATs) has gained great attention in the last decades. Here, we present the synthesis, experimental and theoretical study of the novel regioregular poly(3-adamantylmethylthiophene) (PMAT) and poly(3-adamantylethylthiophene) (PEAT), characterised by a bulky adamantane side group. The prepared compounds are solution-processable in common organic solvents, possess excellent thermal stability up to 491 °C and have unique chemical endurance. The molecular ordering of the polymers was investigated by the GIWAXS technique, and PMAT was found to have the higher content of crystalline phase. The experimental absorption and fluorescence spectra of investigated polymers indicate a higher rigidity of the adamantane side group with respect to torsional rotation in solutions and in thin layers. Electrical measurements exhibit charge carrier mobilities comparable to poly(3-hexylthiophene) (P3HT). In contrast to P3HT, adamantyl-substituted polymers show quasi-reversible reduction alongside the expected quasi-reversible oxidation, which in theory supports the ability to transport both types of electric charges. The newly synthetized regioregular adamantane substituted polythiophenes are serious competitors for a wide range of applications in electronics and optoelectronics.