title: Direct observation and analysis of annealing-induced microstructure at interface and its effect on performance improvement of organic thin film transistors.
abstract: For the first time direct observation and analysis of microstructural variations of crystalline domains and grain boundaries at atomic scale in the buried interface of an organic semiconductor thin film of poly(2,6-bis(3-alkylthiophen-2-yl)dithieno[3,2- b;2',3'- d]thiophene) (PBTDT), a new synthesized solution-processed polymer is achieved for demonstrating a different network nanostructure of crystalline nanofibers at the interface from the outside surface of the film observed. It is also discovered that structural variations of crystalline domains and grain boundaries at an atomic scale caused by annealing, which include larger domains with enhanced crystallinity, reduced pi-pi stacking distance, reduced disorders in the grain boundaries, and small tilt-angle boundaries well explain the significant performance improvement of the PBTDT based organic thin film transistor (OTFT) after annealing. This work provides a highly resolutioned image on the microstructures at an organic semiconducting interface for deep scientific insights of the OTFT performance improvement through microstructure optimization.
authors.affiliation: School of Chemical and Biomedical Engineering and Center for Advanced Bionanosystems, Nanyang Technological University, Singapore 639798, Singapore.
authors.forename: Qiaoliang
authors.initials: Q
authors.lastname: Bao
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Chang Ming
authors.initials: CM
authors.lastname: Li
authors.forename: Zhi Li
authors.initials: ZL
authors.lastname: Dong
authors.forename: Zhisong
authors.initials: Z
authors.lastname: Lu
authors.forename: Fang
authors.initials: F
authors.lastname: Qin
authors.forename: Cheng
authors.initials: C
authors.lastname: Gong
authors.forename: Jun
authors.initials: J
authors.lastname: Guo
mesh_terms: D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D013499:Surface Properties; D013876:Thiophenes / Q000737:chemistry*; D014173:Transistors, Electronic
chemical_list: D013876:Thiophenes