Ultra-high mobility transparent organic thin film transistors grown by an off-centre spin-coating method

• DOI: 10.1038/ncomms4005
• Publication Date: 2014-01-08T12:28:39Z
• Authors: Yongbo Yuan; Gaurav Giri; Alexander L. Ayzner; Arjan P. Zoombelt; Stefan C. B. Mann...; Jihua Chen; Dennis Nordlund; Michael F. Toney; Jinsong Huang; Zhenan Bao
• Keywords: Organic Electronics; Electron Mobility; Spin Coating; Organic semiconductor; Figure of Merit; Benzothiophene

Organic semiconductors with higher carrier mobility and better transparency have been actively pursued for numerous applications, such as flat-panel display backplane and sensor arrays. The carrier mobility is an important figure of merit and is sensitively influenced by the crystallinity and the molecular arrangement in a crystal lattice. Here we describe the growth of a highly aligned meta-stable structure of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) from a blended solution of C8-BTBT and polystyrene by using a novel offcentre spin-coating method. Combined with a vertical phase separation of the blend, the highly aligned, meta-stable C8-BTBT films provide a significantly increased thin film transistor hole mobility up to 43 cm2 Vs1 (25 cm2 Vs1 on average), which is the highest value reported to date for all organic molecules. The resulting transistors show high transparency of 490% over the visible spectrum, indicating their potential for transparent, high-performance organic electronics.