Fully Solution-Processed Flexible Organic Thin Film Transistor Arrays with High Mobility and Exceptional Uniformity

Abstract

Printing fully solution-processed organic electronic devices may potentially revolutionize production of flexible electronics for various applications. However, difficulties in forming thin, flat, uniform films through printing techniques have been responsible for poor device performance and low yields. Here, we report on fully solution-processed organic thin-film transistor (TFT) arrays with greatly improved performance and yields, achieved by layering solution-processable materials such as silver nanoparticle inks, organic semiconductors, and insulating polymers on thin plastic films. A treatment layer improves carrier injection between the source/drain electrodes and the semiconducting layer and dramatically reduces contact resistance. Furthermore, an organic semiconductor with large-crystal grains results in TFT devices with shorter channel lengths and higher field-effect mobilities. We obtained mobilities of over 1.2 cm2 V−1 s−1 in TFT devices with channel lengths shorter than 20 μm. By combining these fabrication techniques, we built highly uniform organic TFT arrays with average mobility levels as high as 0.80 cm2 V−1 s−1 and ideal threshold voltages of 0 V. These results represent major progress in the fabrication of fully solution-processed organic TFT device arrays.

Vacuum production of OTFTs by vapour jet deposition of dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) on a lauryl acrylate functionalised dielectric surface

“…Their performances are also summarised in table 2. Both buffered transistor groups showed equally good on/off ratio of about ~10 5 and mobility of ~0.6 cm 2 /Vs which is significantly higher than the ~ 0.05 cm 2 /Vs obtained from devices made on bare TPGDA. The lauryl acrylate buffered sample showed slightly more negative turn-on and threshold voltages than for the PS buffer, likely due to its slightly higher surface polarity and hence affinity for water.…”

“…To date, most attention has been focused on solution-processing, including spin-coating, ink-jet printing and gravure printing [5,6]. With the solution-processing route material selection is limited by solubility and wetting.…”

Trends in molecular design strategies for ambient stable n-channel organic field effect transistors

“…The ultimate goal is the fabrication of large area roll-to-roll (R2R) printable electronic devices in a cost-effective manner as an alternative to conventional silicon-based technologies. [11][12][13][14] Organic field effect transistors (OFETs) are versatile devices for a variety of applications including radio-frequency identification tags (RFIDs), flexible active-matrix displays, electronic paper, electronic skin, and sensors. 10,[15][16][17][18][19] Moreover, OFETs constitute important parts of integrated circuits (ICs) which are the backbone of modern electronic circuitry.…”

Single Crystal‐Like Performance in Solution‐Coated Thin‐Film Organic Field‐Effect Transistors

“…[3,4] During the last years, significant progresses have been made toward the development of viable printed electronics based on solution-processed organic field-effect transistors (OFETs). [5][6][7] The general guidelines for the requirements of OFETs are: low processing temperature (<120ºC), [8] high on/off ratio (>10 6 ), [9] high reproducibility, [10] high uniformity [11] and high stability (temperature, [12] bias stress [13] and lifetime [14] ). However, all these requirements do not typically coexist in printed OFETs, thus hampering their further exploitation and success in large-area electronics applications.…”