Fully-Printed Stretchable Thin-Film Transistors and Integrated Logic Circuits
AssigneeBoard of Trustees of Michigan State University
InventorsChuan Wang, Le Cai
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Abstract
Printable and stretchable thin-film devices and fabrication techniques are provided for forming fully-printed, intrinsically stretchable thin-film transistors and integrated logic circuits using stretchable elastomer substrates such as polydimethylsiloxane (PDMS), semiconducting carbon nanotube network as channel, unsorted carbon nanotube network as source/drain/gate electrodes, and BaTiO3/PDMS composite as gate dielectric. Printable stretchable dielectric layer ink may be formed by mixing barium titanate nanoparticle (BaTiO3) with PDMS using 4-methyl-2-pentanone as solvent.
Claims25
A thin-film device comprising:
- a stretchable elastomer substrate;
- and
- one or more thin-film transistor elements having a source, a drain, and/or a gate electrode formed of carbon nanotubes (CNTs) and having a stretchable hybrid gate dielectric, the one or more thin-film transistor elements being printed on the stretchable elastomer substrate and forming one or more stretchable thin-film transistor elements.
A method of formulating a printable stretchable dielectric layer ink, the method comprising:
- mixing nanoparticles with high dielectric constant with a stretchable elastomer oligomer in a suitable solvent to form the printable stretchable dielectric ink.
A method of forming stretchable thin-film transistor elements using printing, the method comprising:
- mixing polydimethylsiloxane (PDMS), barium titanate nanoparticles (BaTiO3), and 4-methyl-2-pentanone to form a mixture and performing magnetic stirring on the mixture;
- subjecting the magnetic stirred mixture to successive bath sonication and probe sonication to break aggregations of BaTiO3 to form a stretchable dielectric ink;
- providing an O2 plasma treatment to surface of a PDMS substrate to render the PDMS substrate hydrophilic, and functionalizing the PDMS substrate with poly-L-lysine;
- depositing a semiconducting carbon nanotube network on the PDMS substrate using drop-casting;
- rinsing the PDMS substrate with deionized water to remove excessive surfactant followed by blow drying with N2;
- patterning a source electrode of the thin-film transistor elements and a drain electrode of the thin-film transistor elements by printing unsorted carbon nanotube ink on the substrate for 40˜50 layers at 60° C. using a microplotter equipped with micropipettes;
- defining a channel between the source electrode and the drain electrode by patterning a semiconducting single-walled carbon nanotubes (sSWCNT) network by O2 plasma etching;
- printing a PDMS/BaTiO3 gate dielectric and curing the PDMS/BaTiO3 gate dielectric;
- printing the unsorted carbon nanotube ink on the PDMS/BaTiO3 gate dielectric for 20-30 layers at 60° C. to form a gate electrode of the thin-film transistor elements;
- and
- encapsulating the resulting structure.
Dependencies are inferred from the claim text.