Morphological Characterization of Spray-Coated PCBM Thin Films

• Published in: E-journal of surface science and nanotechnology Vol. 10; pp. 538 - 541
• Main Authors: Lüttich, Franziska, Lehmann, Daniel, Seidel, Falko, Zahn, Dietrich R. T., Graaf, Harald, Borczyskowski, Christian von
• Format: Journal Article
• Language: English
• Published: The Japan Society of Vacuum and Surface Science 01-01-2012
• Subjects: Ellipsometry; Optical microscope; Organic semiconductor; PCBM; Spray-coating
• ISSN: 1348-0391; 1348-0391
• DOI: 10.1380/ejssnt.2012.538

Spray-coating is an interesting alternative technique for producing large area and flexible electronics. However, spray-coated organic films deposited on heated substrates exhibit in general high roughness and inhomogeneous morphologies. The large free-parameter zoo of a spray coating set-up makes it difficult to optimize film deposition. Therefore we present a systematic and quantitative study focusing on spray-parameters like choice of solvent, substrate temperature, carrier gas pressure, and nozzle to substrate distance. We used [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) dissolved in chlorobenzene, toluene, and chloroform, respectively, and deposited it on thermal silicon dioxide substrates. As a critical parameter the substrate temperature was identified, influencing the PCBM surface coverage of the substrate. For the carrier gas pressure a linear influence on the coverage was observed, where the linear dependence correlates with the boiling temperature of the solvent used. [DOI: 10.1380/ejssnt.2012.538]