All-Organic Vapor Sensor Using Inkjet-Printed Reduced Graphene Oxide

Films of graphene oxide and reduced graphene oxide are printed onto a flexible plastic surface (see picture), using inkjet techniques, which are used to detect chemically aggressive vapors such as NO₂ and Cl₂. Vapors in the 100 ppm–500 ppb concentration range can be detected in an air sample without the aid of a vapor concentrator.

http://onlinelibrary.wiley.com/doi/10.1002/anie.200905089/abstract


Angew. Chem. Int. Ed. 2010, 49, 2154 –2157

Dispersion of Alkyl-Chain-Functionalized Reduced Graphene Oxide Sheets in Nonpolar Solvents

Alkyl chains were grafted onto reduced graphene oxide sheets to allow their dispersion in toluene, a common and representative nonpolar solvent. The grafting occurred on a variety of oxygen-containing functionalities already present on reduced graphene oxide, such as hydroxyl and epoxide groups. The structure and the defect density of the sheets were not significantly altered during the synthesis. When dispersed in water−toluene mixtures, phase transfer from the aqueous to the organic phase was observed upon grafting. In addition, the dry powder obtained readily disperses in common organic solvents without the assistance of any sonication treatment.

http://pubs.acs.org/doi/abs/10.1021/la2051614

Langmuir. 2012, 28, 6691−6697

Graphene-Based Conducting Inks for Direct Inkjet Printing of Flexible Conductive Patterns and Their Applications in Electric Circuits and Chemical Sensors

A series of inkjet printing processes have been studied using graphene-based inks. Under optimized conditions, using water-soluble single-layered graphene oxide (GO) and few-layered graphene oxide (FGO), various high image quality patterns could be printed on diverse flexible substrates, including paper, poly(ethylene terephthalate) (PET) and polyimide (PI), with a simple and low-cost inkjet printing technique. The graphene-based patterns printed on plastic substrates demonstrated a high electrical conductivity after thermal reduction, and more importantly, they retained the same conductivity over severe bending cycles. Accordingly, flexible electric circuits and a hydrogen peroxide chemical sensor were fabricated and showed excellent performances, demonstrating the applications of this simple and practical inkjet printing technique using graphene inks. The results show that graphene materials—which can be easily produced on a large scale and possess outstanding electronic properties—have great potential for the convenient fabrication of flexible and low-cost graphene based electronic devices, by using a simple inkjet printing technique.

http://nanocenter.nankai.edu.cn/script/nanocenter/PDF/Nano%20Res_2011_LH.pdf

Nano Res. 2011, 4(7): 675–684

Structural evolution during the reduction of chemically derived graphene oxide

The excellent electrical, optical and mechanical properties of graphene have driven the search to find methods for its large-scale production, but established procedures (such as mechanical exfoliation or chemical vapour deposition) are not ideal for the manufacture of processable graphene sheets. An alternative method is the reduction of graphene oxide, a material that shares the same atomically thin structural framework as graphene, but bears oxygen-containing functional groups. Here we use molecular dynamics simulations to study the atomistic structure of progressively reduced graphene oxide. The chemical changes of oxygen-containing functional groups on the annealing of graphene oxide are elucidated and the simulations reveal the formation of highly stable carbonyl and ether groups that hinder its complete reduction to graphene. The calculations are supported by infrared and X-ray photoelectron spectroscopy measurements. Finally, more effective reduction treatments to improve the reduction of graphene oxide are proposed.


http://www.nature.com/nchem/journal/v2/n7/abs/nchem.686.html

Nature Chemistry, 2010,

2,

 

581–587.

High-quality single-layer graphene via reparative reduction of graphene oxide

Reduction of graphene oxide (GO) is a promising low-cost synthetic approach to bulk graphene, which offers an accessible route to transparent conducting films and flexible electronics. Unfortunately, the release of oxygen-containing functional groups inevitably leaves behind vacancies and topological defects on the reduced GO sheet, and its low electrical conductivity hinders the development of practical applications. Here, we present a strategy for real-time repair of the newborn vacancies with carbon radicals produced by thermal decomposition of a suitable precursor. The sheet conductivity of thus-obtained single-layer graphene was raised more than six-fold to 350–410 S/cm (whilst retaining >96% transparency). X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy revealed that the conductivity enhancement can be attributed to the formation of additional sp2-C structures. This method provides a simple and efficient process for obtaining highly conductive transparent graphene films.


http://www.springerlink.com/content/k127017578016174/

Nano Res. 2011, 4(5): 434–439

Highly Heat and Oxidation-Resistant Materials Prepared Using Silicon- Containing Thermosetting Polymers

Highly heat and oxidation-resistant materials prepared using the silicon-containing thermosetting polymer, poly[(phenylsilylene)ethynylene-1,3-phenyleneethynylene] [-Si(Ph)(H)-C􀀁C-C6H4-C􀀁C-] are summarized. This polymer is light, moldable, soluble in solvent, and highly heat resistant. It is prepared by the dehydrogenative cross-coupling reaction of the Si-H bond of phenylsilane and the C-H bond of 1,3 diethynylbenzene in the presence of base catalysts. Applications of the polymer to particularly composite and ceramic materials are reviewed. Other polymers with molecules containing [Si(H)~C􀀁C] units are discussed. The chemistry and possible applications of the [Si(H)~C􀀁C] unit are also discussed.


http://www.benthamscience.com/open/tomsj/articles/V005/152TOMSJ.pdf

The Open Materials Science Journal, 2011, 5, 152-161

Solvent effects on the charge storage ability in polypyrrole

Solvent e€ect on the charge storage ability of the polypyrrole have been studied in two di€erent ways: analyzing
both the ion-solvent and polymer-solvent interactions and by a multiple regression procedure. The first way was not sucient to explain all the results obtained. By the multiple regression, influence of the four di€erent variables of the solvents simultaneously has been obtained. Solvents having high dipole moments and low polarizability and having a high capacity to donate electrons are the best solvents among those investigated in this paper to obtain high charge storage abilities.


http://www.upct.es/~equimica/laboratorio/ArticulosenPDF/Electrochim.%20Acta/1999%20Electrochim.%20Acta%2044pg2053.pdf

Electrochimica Acta 44 (1999) 2053±2059