Premium
Thin Films of Photoactive Polymer Blends
Author(s) -
Ruderer Matthias A.,
Metwalli Ezzeldin,
Wang Weinan,
Kaune Gunar,
Roth Stephan V.,
MüllerBuschbaum Peter
Publication year - 2009
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200800773
Subject(s) - materials science , contact angle , polymer , wetting , thin film , spin coating , scattering , polymer blend , chemical engineering , photoactive layer , grazing incidence small angle scattering , polymer chemistry , optics , polymer solar cell , composite material , nanotechnology , copolymer , small angle neutron scattering , physics , engineering , neutron scattering
Photoactive polymer blends: Films consisting of two photoactive homopolymers, MEH‐PPV and P3HT, are prepared via spin coating. Investigation of the lateral domain distance inside the blended film, performed by using grazing incidence small angle X‐ray scattering techniques, shows that the theoretically predicted blending ratio seems most promising (see figure).The morphology inside photoactive blended films of two conjugated homopolymers poly [(1‐methoxy)‐4‐(2‐ethylhexyloxy)‐p‐phenylene‐vinylene] (MEH‐PPV) and poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) is investigated. For both homopolymers a linear dependence of the installed film thickness from the concentration of the polymer solution used in spin coating is probed. This dependence allows preparation of an efficient series of blended films with constant thickness and different blending ratios. Information about the lateral structure inside the films is gained from grazing incidence small angle X‐ray scattering. At the calculated critical blending ratio the smallest lateral separation between adjacent domains is found representing the highest surface contact between both homopolymers in the films. The presence of wetting layers at both interfaces as detected with X‐ray reflectivity and atomic force microscopy is promising for photovoltaic applications. UV/Vis spectroscopy complements the structural investigation.