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Enhancement in crystallinity of poly(3‐hexylthiophene) thin films prepared by low‐temperature drop casting
Author(s) -
Salammal Shabi Thankaraj,
Grigorian Souren,
Brinkmann Martin,
Pietsch Ullrich,
Koenen Nils,
Kayunkid Navaphun,
Scherf Ullrich
Publication year - 2012
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.36447
Subject(s) - materials science , crystallinity , chemical engineering , crystallite , annealing (glass) , thin film , transmission electron microscopy , drop (telecommunication) , polymer chemistry , composite material , nanotechnology , telecommunications , computer science , engineering , metallurgy
Low‐temperature casting of high molecular weight (HMW > 40 kDa) regioregular poly(3‐hexylthiophene) (P3HT) is demonstrated to yield highly crystalline P3HT thin films with well defined and preferentially edge‐on oriented [(100) contact plane] nanocrystallites on the pure and silanized Si/SiO 2 substrates. Transmission electron microscopy and X‐ray diffraction provide evidence for the increase in preferential edge‐on orientation of P3HT‐conjugated backbone while decreasing the film preparation temperature below room temperature. The optimum growth temperature is about −12°C for the given concentration (2 mg/mL in CHCl 3 ). The reduced evaporation rate of the solvent results in a better selection of the thermodynamically stable orientation of nanocrystallites onto the substrate. The degree of preferential orientation and size of the crystallites can be further increased on n ‐octadecyltrichlorosilane‐treated SiO 2 substrates as well as by annealing the films at 200°C for 1 h. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012