Chappell John, Lidzey David G, Jukes Paul C, Higgins Anthony M, Thompson Richard L, O'Connor Stephen, Grizzi Ilaria, Fletcher Robert, O'Brien Jim, Geoghegan Mark, Jones Richard A L
Department of Physics and Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK.
Nat Mater. 2003 Sep;2(9):616-21. doi: 10.1038/nmat959. Epub 2003 Aug 17.
Blends of conjugated polymers are frequently used as the active semiconducting layer in light-emitting diodes and photovoltaic devices. Here we report the use of scanning near-field optical microscopy, scanning force microscopy and nuclear-reaction analysis to study the structure of a thin film of a phase-separated blend of two conjugated polymers prepared by spin-casting. We show that in addition to the well-known micrometre-scale phase-separated morphology of the blend, one of the polymers preferentially wets the surface and forms a 10-nm-thick, partially crystallized wetting layer. Using near-field microscopy we identify unexpected changes in the fluorescence emission from the blend that occurs in a 300-nm-wide band located at the interface between the different phase-separated domains. Our measurements provide an insight into the complex structure of phase-separated conjugated-polymer thin films. Characterizing and controlling the properties of the interfaces in such films will be critical in the further development of efficient optoelectronic devices.
共轭聚合物共混物经常被用作发光二极管和光伏器件中的活性半导体层。在此，我们报告了利用扫描近场光学显微镜、扫描力显微镜和核反应分析来研究通过旋涂制备的两种共轭聚合物相分离共混物薄膜的结构。我们表明，除了共混物中众所周知的微米级相分离形态外，其中一种聚合物优先润湿表面并形成一个10纳米厚的部分结晶的润湿层。利用近场显微镜，我们识别出在位于不同相分离域之间界面处的一个300纳米宽带中发生的共混物荧光发射的意外变化。我们的测量为相分离共轭聚合物薄膜的复杂结构提供了深入了解。表征和控制此类薄膜中界面的性质对于高效光电器件的进一步发展至关重要。
