Experimental Study and Statistical Analysis of Solution-Shearing Processed Organic Transistors Based on an Asymmetric Small-Molecule Semiconductor

Abstract

Solution processed organic field-effect transistors (SPOFETs) are crucial for realizing low-cost large-area/ubiquitous flexible electronics. Currently, both soluble high-mobility organic semiconductors and efficient solution processes are in demand. In this paper, we report the systematic experimental study and statistical modeling/analysis for the SPOFETs based on an asymmetric small-molecule organic semiconductor, trimethyl-[2, 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">'</sup> ; 5 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">'</sup> , 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">''</sup> ; 5 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">''</sup> , 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">'''</sup> ] quarter-thiophen-5-yl-silane (4 T-TMS), which was deposited as the active layer through a recently developed low-temperature solution-shearing process. Three-dimensional statistical modeling and analysis bas ed on 46 different processing conditions was used to comprehensively study the solution-shearing process control and optimization for fabricating high-performance 4T-TMS SPOFETs. Various effects including solution concentration effect, shearing speed effect, and deposition temperature effect were investigated and discussed. Under optimized processing conditions, well-oriented crystalline 4 T-TMS thin films were deposited for the SPOFETs, which showed remarkable effective field-effect mobility up to 0.3 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V middots in the saturation region and current on/off ratios over 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> . Gaussian fitted uniformity and good air stability of these devices stored and tested under ambient conditions for six months suggest that 4 T-TMS SPOFETs based on the optimized solution-shearing process are promising for applications in organic electronic circuits and displays. Importantly, the systematic experiment design and the corresponding statistical modeling/analysis presented here provide a general guideline for process optimization for fabricating high-performance SPOFETs.