Graphene-enabled adaptive infrared textiles

Interactive clothing requires sensing and display functionalities to be embedded on textiles. Despite the significant progress of electronic textiles, the integration of optoelectronic materials on fabrics remains as an outstanding challenge. In this Letter, using the electro-optical tunability of graphene, we report adaptive optical textiles with electrically controlled reflectivity and emissivity covering the infrared and near-infrared wavelengths. We achieve electro-optical modulation by reversible intercalation of ions into graphene layers laminated on fabrics. We demonstrate a new class of infrared textile devices including display, yarn, and stretchable devices using natural and synthetic textiles. To show the promise of our approach, we fabricated an active device directly onto a t-shirt, which enables long-wavelength infrared communication via modulation of the thermal radiation from the human body. The results presented here provide complementary technologies which could leverage the ubiquitous use of functional textiles

Influence of defect density on the gas sensing properties of multi-layered graphene grown by chemical vapor deposition

Chemical vapor deposition (CVD) has been demonstrated as a highly promising technique for the production of graphene on large scale and enabling tunability of the intrinsic defects of the films during the synthesis.In this work, we report on the correlation between the density of defects (DoD) and the kinetics of interaction of multi-layered graphene (MLG) with nitrogen dioxide (NO2) used as a target gas. We grow MLG on a pre-patterned molybdenum (Mo) catalyst layer, tailoring the DoD while growing MLG at temperatures from 850 °C to 980 °C. Analysing the Raman spectra, we show the lowering of the DoD as well as a quality dependence of MLG as a function of the growth temperature. The chemi-resistors based on MLG grown at different temperatures unambiguously highlight that, both during the exposure and the subsequent purge phase, the more defective the MLG, the more intense the NO2’s molecules interaction with MLG. Our results significantly mark a step forward in tuning the sensing properties of MLG without the need of any post-processing of the material after synthesis.Electronic InstrumentationElectronic Components, Technology and Material

Initial Studies Directed toward the Rational Design of Aqueous Graphene Dispersants

This study presents preliminary experimental data suggesting that sodium 4-(pyrene-1-yl)­butane-1-sulfonate (PBSA), <b>5</b>, an analogue of sodium pyrene-1-sulfonate (PSA), <b>1</b>, enhances the stability of aqueous reduced graphene oxide (RGO) graphene dispersions. We find that RGO and exfoliated graphene dispersions prepared in the presence of <b>5</b> are approximately double the concentration of those made with commercially available PSA, <b>1</b>. Quantum mechanical and molecular dynamics simulations provide key insights into the behavior of these molecules on the graphene surface. The seemingly obvious introduction of a polar sulfonate head group linked via an appropriate alkyl spacer to the aromatic core results in both more efficient binding of <b>5</b> to the graphene surface and more efficient solvation of the polar head group by bulk solvent (water). Overall, this improves the stabilization of the graphene flakes by disfavoring dissociation of the stabilizer from the graphene surface and inhibiting reaggregation by electrostatic and steric repulsion. These insights are currently the subject of further investigations in an attempt to develop a rational approach to the design of more effective dispersing agents for rGO and graphene in aqueous solution