Room-Temperature Self-Organizing Characteristics of Soluble Acene Field-Effect Transistors

We report on the room‐temperature self‐organizing characteristics of thin films of the organic small‐molecule semiconductor triethylsilylethynyl‐anthradithiophene (TES‐ADT) and its effect on the electrical properties of TES‐ADT‐based field‐effect transistors (FETs). The morphology of TES‐ADT films changed dramatically with time, and the field‐effect mobility of FETs based on these films increased about 100‐fold after seven days as a result of the change in molecular orientation from a tilted structure in the as‐prepared film to a well‐oriented structure in the final film. We found that the molecular movement is large enough to induce a conformational change to an energetically stable state in spin‐coated TES‐ADT films, because TES‐ADT has a low glass‐transition temperature (around room temperature). Our findings demonstrate that organic small‐molecule semiconductors that exhibit a low crystallinity immediately after spin‐coating can be changed into highly crystalline structures by spontaneous self‐organization of the molecules at room temperature, which results in improved electrical properties of FETs based on these semiconductors. Spontaneous self‐organization at room temperature induces dramatic changes in the morphology of triethylsilylethynyl‐anthradithiophene films over a couple of days. The field‐effect mobility of field‐effect transistors based on these films increases about 100‐fold after 7 days as a result of the change of molecular orientation from a tilted structure in the as‐prepared film to a well‐oriented structure in the final film (see figure)