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Depletion of PCBM at the Cathode Interface in P3HT/PCBM Thin Films as Quantified via Neutron Reflectivity Measurements
Author(s) -
Parnell Andrew J.,
Dunbar Alan D. F.,
Pearson Andrew J.,
Staniec Paul A.,
Dennison Andrew J. C.,
Hamamatsu Hiroshi,
Skoda Maximilian W. A.,
Lidzey David G.,
Jones Richard. A. L.
Publication year - 2010
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.200903971
Subject(s) - materials science , reflectivity , cathode , x ray reflectivity , thin film , optoelectronics , neutron , interface (matter) , nanotechnology , optics , composite material , chemistry , quantum mechanics , capillary number , capillary action , physics
Using neutron reflectivity, self‐stratification in a model P3HT/PCBM blend is observed. The as‐spun and solvent‐annealed films show a depletion of PCBM near the top surface and enrichment of PCBM at the substrate (see figure). Depletion of PCBM at the cathode interface in a photovoltaic device could act as a barrier to efficient electron extraction. On thermal annealing, the PCBM depleted region is eliminated; an effect that partially explains the improvement of P3HT/PCBM devices on thermal annealing.