TY - JOUR A1 - Boufflet, Pierre A1 - Wood, Sebastian A1 - Wade, Jessica A1 - Fei, Zhuping A1 - Kim, Ji-Seon A1 - Heeney, Martin T1 - Comparing blends and blocks: Synthesis of partially fluorinated diblock polythiophene copolymers to investigate the thermal stability of optical and morphological properties JF - Beilstein Journal of Organic Chemistry PY - 2016/// VL - 12 SP - 2150 EP - 2163 SN - 1860-5397 DO - 10.3762/bjoc.12.205 PB - Beilstein-Institut JA - Beilstein J. Org. Chem. UR - https://doi.org/10.3762/bjoc.12.205 KW - conjugated block-copolymer synthesis KW - fluorination KW - microphase stabilization KW - polythiophene KW - temperature-dependent Raman spectroscopy N2 - The microstructure of the active blend layer has been shown to be a critically important factor in the performance of organic solar devices. Block copolymers provide a potentially interesting avenue for controlling this active layer microstructure in solar cell blends. Here we explore the impact of backbone fluorination in block copolymers of poly(3-octyl-4-fluorothiophene)s and poly(3-octylthiophene) (F-P3OT-b-P3OT). Two block co-polymers with varying block lengths were prepared via sequential monomer addition under Kumada catalyst transfer polymerisation (KCTP) conditions. We compare the behavior of the block copolymer to that of the corresponding homopolymer blends. In both types of system, we find the fluorinated segments tend to dominate the UV–visible absorption and molecular vibrational spectral features, as well as the thermal behavior. In the block copolymer case, non-fluorinated segments appear to slightly frustrate the aggregation of the more fluorinated block. However, in situ temperature dependent Raman spectroscopy shows that the intramolecular order is more thermally stable in the block copolymer than in the corresponding blend, suggesting that such materials may be interesting for enhanced thermal stability of organic photovoltaic active layers based on similar systems. ER -