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Fast scanning chip calorimetry study of P3HT/PC 61 BM submicron layers: structure formation and eutectic behaviour
Author(s) -
Van den Brande Niko,
Van Assche Guy,
Van Mele Bruno
Publication year - 2019
Publication title -
polymer international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.592
H-Index - 105
eISSN - 1097-0126
pISSN - 0959-8103
DOI - 10.1002/pi.5672
Subject(s) - eutectic system , isothermal process , differential scanning calorimetry , materials science , crystallization , amorphous solid , analytical chemistry (journal) , vitrification , phase (matter) , chemical engineering , crystallography , thermodynamics , chemistry , chromatography , organic chemistry , microstructure , composite material , physics , engineering , nuclear physics
Fast scanning chip calorimetry was used to perform an elaborate isothermal study of poly(3‐hexyl thiophene)/[6,6]‐phenyl‐C 61 ‐butyric acid methyl ester (P3HT/PC 61 BM) submicron layers. The used scanning rates of 30 000 K s −1 allow for a ‘true’ isothermal study, where non‐isothermal effects are avoided. Results were obtained over a wide temperature range for the 1:1 composition, used in organic solar cells, and for selected temperatures for the 3:7 composition. The results can be clearly interpreted according to the eutectic behaviour expected for this system, with the 1:1 composition being enriched in P3HT and the 3:7 composition being enriched in PC 61 BM. In both cases, the start of the melting trajectory corresponding to the eutectic transition coincided with the T g of PC 61 BM. This is in agreement with earlier studies that report a vitrification effect caused by PC 61 BM. A bell‐shaped curve of isothermal crystallization rates could be constructed for the 1:1 composition, where the T g of the mixed amorphous phase as well as of the separate components can be seen to play a role. For the 3:7 composition, clear indications are observed that a vitrified PC 61 BM phase can be formed in which isothermal crystallization takes place. © 2018 Society of Chemical Industry