Electronic Engineering Department, The Chinese University of Hong Kong - Prof. J.B. Xu

A recent article entitled "Controlling of the surface energy of the gate dielectric in organic field-effect transistors by polymer blend" (Appl. Phys. Lett. 2009, 94, 093302) by Prof. J.B. Xu's team and collaborators has been highlighted by "Noteworthy Chemistry", a weekly feature produced by the American Chemical Society (ACS) that collects and summarizes innovative ideas and has become a valuable stand alone resource for today’s informed chemistry professional.

Highlight by Noteworthy Chemistry:

Match surface energies to obtain high field-effect mobility. Organic field-effect transistors (OFETs) play an essential role in making low-cost, large-area electronic products. Much effort has been devoted to modifying dielectric–semiconductor interfaces to adjust the surface energy of the gate dielectric and enhance field-effect mobility.

Polymeric dielectrics are promising gate materials for making flexible OFETs. Controlling the surface energy of the gate dielectric and the morphology of the semiconductor deposited onto it, however, is challenging. J. Gao, J. B. Xu, and coauthors at the Chinese University of Hong Kong and the University of Groningen (The Netherlands) attacked this problem with a simple approach.

The researchers built OFETs by depositing copper phthalocyanine (CuPc) semiconductors onto dielectric layers of poly(methyl methacrylate) (PMMA)–polystyrene (PS) blends. The highest field-effect mobility [0.01 cm2/(V∙s)] is obtained when the surface energy of the polymer dielectrics is modulated to match that of the semiconductor by adjusting the PMMA/PS blend ratio to 1:3. The high mobility results from the desired morphology and favors growth of CuPc on the dielectric layer. This finding demonstrates the advantage of using insulating polymer blends to control the surface energy of the gate dielectric to achieve better OFET performance. (Appl. Phys. Lett. 2009, 94, 093302; Ben Zhong Tang)”

Noteworthy Chemistry – April 6, 2009