Monolayer crystal structure of the organic semiconductor 7-decyl-2-phenyl[1]benzothieno[3,2-b][1]benzothiophene, revisited

The monolayer crystal phase structure of the organic semiconductor 7-decyl-2-phenyl[1]benzothieno[3,2-b][1]benzothiophene was reinvestigated. A smaller two- or three-step bilayer-monolayer transition model than the previous transition model was newly proposed. The carrier mobilities of the resultant two monolayer crystal structure models were theoretically compared. The results show that the antiparallel monolayer crystal model that can be transformed with only two steps (without any rotation) from the bilayer structure is more probable than the nanosegregated model.