Photoinduced charge transfer within polyaniline-encapsulated quantum dots decorated on graphene.

A new method to enhance the stability of quantum dots (QDs) in aqueous solution by encapsulating them with conducting polymer polyaniline was reported. The polyaniline-encapsulated QDs were then decorated onto graphene through π-π interactions between graphene and conjugated polymer shell of QDs, forming stable polyaniline/QD/graphene hybrid. A testing electronic device was fabricated using the hybrid in order to investigate the photoinduced charge transfer between graphene and encapsulated QDs within the hybrid.

Recent advancements of graphene in biomedicine.

Graphene, as a rising star in the field of nanomaterials, possesses a unique planar structure and exceptional electronic, mechanical, and optical properties. The material has attracted tremendous interest not only for its intrinsic properties but also promising application opportunities in a wide range of technologies and markets. This review specifically summarizes recent research advancements of graphene in the areas of biotechnology and biomedicine.

Chemo-sensors development based on low-dimensional codoped Mn2O3-ZnO nanoparticles using flat-silver electrodes.

Background: Semiconductor doped nanostructure materials have attained considerable attention owing to their electronic, opto-electronic, para-magnetic, photo-catalysis, electro-chemical, mechanical behaviors and their potential applications in different research areas. Doped nanomaterials might be a promising owing to their high-specific surface-area, low-resistances, high-catalytic activity, attractive electro-chemical and optical properties. Nanomaterials are also scientifically significant transition metal-doped nanostructure materials owing to their extraordinary mechanical, optical, electrical, electronic, thermal, and magnetic characteristics.

Flexible organic light-emitting diodes with transparent carbon nanotube electrodes: problems and solutions.

We study in detail here the application of transparent, conductive carbon single-wall nanotube (SWNT) networks as electrodes in flexible organic light-emitting diodes (FOLEDs). Overall comparisons of these networks to the commonly used electrodes poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) and indium tin oxide (ITO) are made, and SWNT networks are shown to have excellent optical and superior mechanical properties. The effects of protruding nanotubes, rough surface morphology, and SWNT network-adjacent layer dewetting are shown to be problematic, and approaches for addressing these issues are identified.

A method of fabricating highly transparent and conductive interpenetrated carbon nanotube-parylene networks.

We report a method of fabrication of free standing and ultra-thin carbon nanotube-parylene-C interpenetrating networks. The network is highly transparent, highly flexible, and more conductive than transparent nanotube/polymer composites. Scanning electron microscope imaging reveals that the interpenetrated networks are dense and pinhole free compared to bare nanotube networks.

Surface-modified nanotube anodes for high performance organic light-emitting diode.

In this work, we reported high performance OLED devices with transparent and conductive carbon nanotube anodes after modification. The modifications include IMRE proprietary PEDOT:PSS composite top coating (PS(C)), concentrated HNO(3) acid soaking, and polymer encapsulation. For PS(C)-modified nanotube thin film anode, we achieved maximum luminescence of approximately 9000 cd/m(2), close to ITO-based OLED device performance, and high efficiency of approximately 10 cd/A, similar with ITO-based OLED device.

Printable thin film supercapacitors using single-walled carbon nanotubes.

Thin film supercapacitors were fabricated using printable materials to make flexible devices on plastic. The active electrodes were made from sprayed networks of single-walled carbon nanotubes (SWCNTs) serving as both electrodes and charge collectors. Using a printable aqueous gel electrolyte as well as an organic liquid electrolyte, the performances of the devices show very high energy and power densities (6 W h/kg for both electrolytes and 23 and 70 kW/kg for aqueous gel electrolyte and organic electrolyte, respectively) which is comparable to performance in other SWCNT-based supercapacitor devices fabricated using different methods.

Charge transport in interpenetrating networks of semiconducting and metallic carbon nanotubes.

Carbon nanotube network field effect transistors (CNTN-FETs) are promising candidates for low cost macroelectronics. We investigate the microscopic transport in these devices using electric force microscopy and simulations. We find that in many CNTN-FETs the voltage drops abruptly at a point in the channel where the current is constricted to just one tube.

A tunable photosensor.

A pyrene-modified beta-cyclodextrin (pyrenecyclodextrin)-decorated single-walled carbon nanotube (SWNT) field-effect transistor (FET) device was fabricated, which can serve as a tunable photosensor to sense a fluorescent adamantyl-modified Ru complex (ADA-Ru). When the light is on (I = 40 W m(-2) and lambda = 280 nm), the transfer curve of the pyrenecyclodextrin-SWNT/FET device shifts toward a negative gate voltage by about 1.6 V and its sheet resistance increases quickly, indicating a charge-transfer process from the pyrenecyclodextrins to the SWNTs.

Organic light-emitting diodes having carbon nanotube anodes.

Single-walled carbon nanotube (SWNT) films on flexible PET (polyethyleneterephthalate) substrates are used as transparent, flexible anodes for organic light-emitting diodes (OLEDs). For polymer-based OLEDs having the structure: SWNT/PEDOT-PSS:MeOH/TFB (poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine)) + TPD-Si(2) (4,4'-bis[(p-trichlorosilylpropylphenyl)phenylamino]biphenyl) /BT (poly(9,9-dioctylfluorene-co-benzothiadiazole))/CsF/Al, a maximum light output of 3500 cd/m(2) and a current efficiency of 1.6 cd/A have been achieved.

Bioinspired detection of light using a porphyrin-sensitized single-wall nanotube field effect transistor.

Single-wall carbon nanotube (SWNT) field effect transistors (FETs), functionalized noncovalently with a zinc porphyrin derivative, were used to directly detect a photoinduced electron transfer (PET) within a donor/acceptor (D/A) system. We report here that the SWNTs act as the electron donor and the porphyrin molecules as the electron acceptor. The magnitude of the PET was measured to be a function of both the wavelength and intensity of applied light, with a maximum value of 0.

Electronic detection of the enzymatic degradation of starch.

[reaction: see text] The enzymatic degradation of starch can be monitored electronically using single-walled carbon nanotubes (SWNTs) as semiconducting probes in field-effect transistors (FETs). Incubation of these devices in aqueous buffer solutions of amyloglucosidase (AMG) results in the removal of the starch from both the silicon surfaces and the side walls of the SWNTs in the FETs, as evidenced by direct imaging and electronic measurements.

Charge transfer from ammonia physisorbed on nanotubes.

We report the use of nanotube field-effect transistor devices for chemical sensing in a conducting liquid environment. Detection of ammonia occurs through the shift of the gate voltage dependence of the source-drain current. We attribute this shift to charge transfer from adsorbed ammonia molecules, with the amount of charge estimated to be as small as 40 electrons for the smallest shift detected.