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'; 5', 2''; 5'', 2'''] 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 cm2/V middots in the saturation region and current on/off ratios over 106. 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.
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ABSTRACT: C-60-based organic thin film transistors (OTFTs) with high electron mobility and high operational stability are achieved with (1 1 1) oriented C-60 films grown by using template effects of diindenoperylene (DIP) under layer on the SiO2 gate insulator. The electron mobility of the C60 transistor is significantly increased from 0.21 cm(2) V-1 s(-1) to 2.92 cm(2) V-1 S-1 by inserting the template-DIP layer. Moreover much higher operational stability is also observed for the DIP-template C-60 OTFTs. A grazing incidence X-ray diffraction and ultra-high-sensitivity photoelectron spectroscopy measurements indicate that the improved electron mobility and stability arise from the decreased density of trap states in the C-60 film due to increased (1 1 1) orientation of C-60-grains and their crystallinity on the DIP template.Organic Electronics 11/2014; 15(11):2749–2755. DOI:10.1016/j.orgel.2014.07.010 · 3.68 Impact Factor
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ABSTRACT: Methods for the solution deposition of organic semiconductors (OSCs) show great potential for the production of large-area, inexpensive, and flexible organic electronics. A solution deposition method called solution shearing has consistently been shown to yield thin film transistors with improved performance over those created via other solution-based approaches. However, the need for discrete, electronically isolated devices requires the parallel development of a facile means of pattern definition compatible with the solution shearing process. In our work, we use a simple chemical prepatterning method to enable the solution shearing deposition of the small molecule OSC TIPS-pentacene on substrates with feature sizes as small as 100 mu m. Grazing incidence x-ray diffraction (GIXD) was also used to confirm the existence of high performance TIPS-pentacene polymorphs in the patterned thin films. Mobilities as high as 1.13 cm(2) V-1 s(-1) were obtained on 400 mu m wide patterns by depositing a high-performance, metastable polymorph of TIPS-pentacene.Journal of Materials Research 10/2014; 29(22). DOI:10.1557/jmr.2014.305 · 1.82 Impact Factor