Tuning of Ag work functions by self-assembled monolayers of aromatic thiols for an efficient hole injection for solution processed triisopropylsilylethynyl pentacene organic thin film transistors

We demonstrate tuning of hole injection barriers in bottom contact triisopropylsilylethynyl pentacene (TIPS-pentacene) organic thin film transistors (OTFTs) by forming the self-assembled monolayers (SAMs) of thiophenol, 4-fluorothiophenol, or pentafluorothiophenol on the pristine Ag electrode. The work functions of SAM-treated Ag electrodes are measured by Kelvin probe method. The TIPS-pentacene OTFT devices were fabricated by a drop-cast method with a micropipette like an inkjet printing. The OTFTs with pentafluorothiophenol-Ag electrodes as source and drain exhibit carrier mobility of 0.17cm2∕Vs and on/off current ratio of 105 because of almost no hole injection barrier to TIPS pentacenes. The SAM-treated Ag electrodes are robust over repeated electrical scans of 100cycles.

[1]  Jean-Luc Brédas,et al.  Introduction to Organic Thin Film Transistors and Design of n-Channel Organic Semiconductors , 2004 .

[2]  Ute Zschieschang,et al.  Low-voltage organic transistors with an amorphous molecular gate dielectric , 2004, Nature.

[3]  Smith,et al.  Controlling Schottky energy barriers in organic electronic devices using self-assembled monolayers. , 1996, Physical review. B, Condensed matter.

[4]  K. Seki,et al.  ENERGY LEVEL ALIGNMENT AND INTERFACIAL ELECTRONIC STRUCTURES AT ORGANIC/METAL AND ORGANIC/ORGANIC INTERFACES , 1999 .

[5]  B. de Boer,et al.  Tuning of Metal Work Functions with Self‐Assembled Monolayers , 2005 .

[6]  Janusz Kowalik,et al.  Pentacene disproportionation during sublimation for field-effect transistors. , 2005, Journal of the American Chemical Society.

[7]  Oana D. Jurchescu,et al.  Effect of impurities on the mobility of single crystal pentacene , 2004, cond-mat/0404130.

[8]  T. Jackson,et al.  Pentacene TFT with improved linear region characteristics using chemically modified source and drain electrodes , 2001, IEEE Electron Device Letters.

[9]  Ping Liu,et al.  Stable Solution-Processed High-Mobility Substituted Pentacene Semiconductors , 2007 .

[10]  John E. Anthony,et al.  High mobility solution processed 6,13-bis(triisopropyl-silylethynyl) pentacene organic thin film transistors , 2007 .

[11]  Wilford N. Hansen,et al.  Standard reference surfaces for work function measurements in air , 2001 .

[12]  Zhenan Bao,et al.  High-performance microscale single-crystal transistors by lithography on an elastomer dielectric , 2006 .

[13]  J S Brooks,et al.  Functionalized pentacene: improved electronic properties from control of solid-state order. , 2001, Journal of the American Chemical Society.

[14]  John E. Anthony,et al.  Functionalized Pentacene Active Layer Organic Thin‐Film Transistors , 2003 .

[15]  Jeong In Han,et al.  High‐Mobility Organic Transistors Based on Single‐Crystalline Microribbons of Triisopropylsilylethynyl Pentacene via Solution‐Phase Self‐Assembly , 2007 .

[16]  D. A. Corley,et al.  Controlling charge injection in organic field-effect transistors using self-assembled monolayers. , 2006, Nano letters.

[17]  Hong Meng,et al.  High-performance, stable organic thin-film field-effect transistors based on bis-5'-alkylthiophen-2'-yl-2,6-anthracene semiconductors. , 2005, Journal of the American Chemical Society.

[18]  D. Bradley,et al.  Using Self‐Assembling Dipole Molecules to Improve Hole Injection in Conjugated Polymers , 2004 .

[19]  Stephen D. Evans,et al.  Surface potential studies of alkyl-thiol monolayers adsorbed on gold , 1990 .

[20]  K. Kudo,et al.  High‐Performance Bottom‐Contact Organic Thin‐Film Transistors with Controlled Molecule‐Crystal/Electrode Interface , 2007 .

[21]  J. Park,et al.  Energy level alignment and two-dimensional structure of pentacene on Au(111) surfaces , 2002 .