Fabrication of organic semiconductor crystalline thin films and crystals from solution by confined crystallization

Highly crystalline thin films of organic semiconductors processed from solution for electronic devices are difficult to achieve due to a slow and preferential three-dimensional growth of the crystals. Here we describe the development of a processing technique to induce a preferential two-dimensional crystalline growth of organic semiconductors by means of minimizing one dimension and confining the solution in two dimensions into a thin layer. The versatility of the process is demonstrated by processing small molecules (TIPS-pentacene and C60) and a polymer (P3HT), all from solvents with a relatively low boiling point, to obtain crystalline thin films. The thin films show an improved in-plane packing of the molecules compared to films processed under similar conditions by spin coating, which is beneficial for the use in organic field-effect transistors.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Confined solution deposition technique. ► Single crystals and crystalline thin films of organic semiconductors. ► Improved electrical characteristics in transistors. ► Versatility demonstrated with crystalline films of polymers and small molecules. ► A fast method for growing crystals without the requirement of an annealing process.