Simple Interface Engineering of Graphene Transistors with Hydrophobizing Stamps

Abstract

We demonstrate a simple surface engineering method for fabricating graphene transistors by using hydrophobizing stamps. By simply contact-printing hydrophobizing stamp that is made with polydimethylsiloxane (PDMS) on a standard silicon substrate for a certain contact-time, it was possible to control the contact angle of the substrate and electrical characteristics of the graphene transistors supported on the substrate. Moreover, graphene transistors supported on the engineered silicon substrate showed improved performances, including an increase in carrier mobility and loss of hysteresis. As a proof-of-concept experiment, a simple logic gate operation was demonstrated by connecting a pristine graphene device with an interface-engineered device.

Kirigami Photopiezo Catalysts for Self-Sustainable Environment Remediation

“…16 Briefly, fully dried ZnO NRs were applied to a typical art brush (nylon fiber flat brush, 27 mm fiber length, 40 μm fiber width) and swept directionally onto the polydimethylsiloxane (PDMS) substrates. The moderate stickiness of the PDMS, with a cured base to curing agent ratio of 10:1, 17 allows for proper rotation of ZnO NRs that are not parallel to the direction of brush motionwhile maintaining alignment with the 1b. Note that this alignment is not just local but global, as the laser diffraction patterns of different spots show highly anisotropic features and high similarity between the data (Supporting Information Figure S3).…”

Graphene as a thin-film catalyst booster: graphene-catalyst interface plays a critical role

“…Two types of PDMS stamps, a '10:1 PDMS stamp' and a '20:1 PDMS stamp', were made by mixing Sylgard 184 (Dow Corning Chemicals, MI, USA) prepolymer and curing agent at 10:1 and 20:1 weight ratios, respectively, and then cured at 80 °C for two hours Each of these stamps were then made to contact cleaned Si substrates (with a 500 nm thick layer of SiO 2 ) for various amounts of time: some substrate samples were treated with the 10:1 PDMS stamp for one second (referred to as 'PDMS1') or three minutes (PDMS2); and, to produce more hydrophobic surfaces, other substrate samples were treated with the 20:1 PDMS stamp, for either one minute (PDMS3) or two hours (PDMS4). In general, when using such a PDMS stamp, non-crosslinked low-molecular weight PDMS spontaneously diffuses out from the bulk PDMS and becomes deposited on the substrate surface, increasing the hydrophobicity of the substrate [25].…”

Development of Screen-Printed Biodegradable Flexible Organic Electrochemical Transistors Enabled by Poly(3,4-ethylenedioxythiophene) Polystyrene Sulfonate and a Solid-State Chitosan Polymer Electrolyte

“…Notable examples include poly(styrene-block-ethylene-oxide-block-styrene) (PS-PEO-PS), 24 poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)), 25 poly(vinylphosphonic acid-co-acrylic acid) (PVPA-AA)), 9 1-ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl) imide ([EMIM][TFSI]), 26 and 1butyl-3-methylimidazolium hexafluorophosphate ([BMIM]-[PF6]). 27 Despite these ionic gels exhibiting promising features, their synthesis is complex and the copolymers used are often costly. Additionally, the ionic liquids used have not been confirmed as biocompatible or biodegradable, and in some cases, they may even be toxic.…”

“…The research on various polymers that are doped with ionic liquids to form ionic gels has been extensively studied. Notable examples include poly­(styrene- block -ethylene-oxide-block-styrene) (PS-PEO-PS), poly­(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP)), poly­(vinylphosphonic acid- co -acrylic acid) (PVPA-AA)), 1-ethyl-3-methylimidazolium bis­(trifluoromethylsulfonyl) imide ([EMIM]­[TFSI]), and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]­[PF6]) . Despite these ionic gels exhibiting promising features, their synthesis is complex and the copolymers used are often costly.…”