Convective self-assembly of π-conjugated oligomers and polymers

Abstract

Here, we apply convective self-assembly, a technique that was developed to deposit nano-to-micrometer-sized colloids onto solid substrates, to conjugated organic matter. We demonstrate its versatility and effectiveness by fabricating uniform, structured films using both oligomeric and macromolecular species and show through specific examples that the optical properties of the created thin-film structures can be readily manipulated by adjusting parameters such as concentration, substrate temperature and deposition. We tentatively attribute this change in optical properties to a change in the molecular conformation of the deposited molecules. Convective self-assembly should be generally applicable to organic semiconductors and, in principle, can be applied to large-area substrates and roll-to-roll procedures, hence, providing a powerful, additional tool for the processing of conjugated organic materials.