Flexible All-organic, All-solution Processed Thin Film Transistor Array with Ultrashort Channel.

Wei Xu,Jian Wang,Zhanhao Hu,Junbiao Peng,Linfeng Lan,Huimin Liu,Yong Cao

doi:10.1038/srep29055

Abstract

Shrinking the device dimension has long been the pursuit of the semiconductor industry to increase the device density and operation speed. In the application of thin film transistors (TFTs), all-organic TFT arrays made by all-solution process are desired for low cost and flexible electronics. One of the greatest challenges is how to achieve ultrashort channel through a cost-effective method. In our study, ultrashort-channel devices are demonstrated by direct inkjet printing conducting polymer as source/drain and gate electrodes without any complicated substrate’s pre-patterning process. By modifying the substrate’s wettability, the conducting polymer’s contact line is pinned during drying process which makes the channel length well-controlled. An organic TFT array of 200 devices with 2 μm channel length is fabricated on flexible substrate through all-solution process. The simple and scalable process to fabricate high resolution organic transistor array offers a low cost approach in the development of flexible and wearable electronics.

Highlights

Organic thin-film transistors (OTFTs) have attracted great attention for a wide range of applications, such as flexible displays[1,2], sensors[3], radio frequency identification tags[4], low-cost memories[5], and microprocessors[6], due to their unique properties of excellent mechanical flexibility and process advantages of being compatible with high throughput and low-budget printing processes[7]
To further exploit the direct-writing capability by inkjet printing, the authors developed a lithography-free nanopatterning technique in which a self-assembled surface layer induced the dewetting of PEDOT:PSS resulting in sub-micrometer size channels[22]
Our study demonstrates that by carefully controlling ink spreading on substrates, high resolution OTFTs are achievable by direct inkjet printing

Summary

Processed Thin Film Transistor

Array with Ultrashort Channel received: 11 March 2016 accepted: 14 June 2016 Published: 05 July 2016. Ultrashort-channel devices are demonstrated by direct inkjet printing conducting polymer as source/ drain and gate electrodes without any complicated substrate’s pre-patterning process. An organic TFT array of 200 devices with 2 μm channel length is fabricated on flexible substrate through all-solution process. The simple and scalable process to fabricate high resolution organic transistor array offers a low cost approach in the development of flexible and wearable electronics. The costly metal deposition in vacuum for preparing the electro-polymerization template was required to deposit the electrodes Another simple and cost-effective patterning technique is inkjet printing. To further exploit the direct-writing capability by inkjet printing, the authors developed a lithography-free nanopatterning technique in which a self-assembled surface layer induced the dewetting of PEDOT:PSS resulting in sub-micrometer size channels[22]. Our study demonstrates that by carefully controlling ink spreading on substrates, high resolution OTFTs are achievable by direct inkjet printing

Results

Methods

Additional Information