Mixing in PCBM/P3HT bilayers, using in situ and ex situ neutron reflectivity. Issue 10 (6th March 2017)

• Record Type: Journal Article
• Authors: Môn, Dyfrig; Higgins, Anthony M.; Gutfreund, Philipp; James, David
• Is Part Of: Journal of materials research. Volume 32:Issue 10(2017)
• Page Start: 1946
• Page End: 1956
• Publication Date: 2017-03-06
• Subjects: polymer, -- mixture, -- neutron scattering; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1557/jmr.2017.59
• Languages: English
• ISSNs: 0884-2914

Abstract

Abstract: Abstract : In situ and ex situ neutron reflectivity is used to characterize annealed regioregular-P3HT/PCBM bilayers. In situ annealing of a 20 nm PCBM/35 nm P3HT bilayer at 170 °C reveals rapid mixing of PCBM and P3HT to produce a polymer-rich layer that contains around 18–20% PCBM. Samples with three different thicknesses of P3HT layer are ex situ annealed at 140 °C. This again reveals migration of PCBM into the P3HT and vice versa, with the polymer-rich layer in the 20 nm PCBM/35 nm P3HT sample containing 19% PCBM. Complete migration of the entire PCBM layer into the P3HT layer is observed for a 20 nm PCBM/80 nm P3HT bilayer. The robustness of fitted model composition profiles, in comparison with real-space imaging of sample surface morphology and previous work on annealed P3HT/PCBM bilayer compositions, is discussed in detail.