Excitation of Surface Plasmon Resonance in Composite Structures Based on Single-Layer Superaligned Carbon Nanotube Films

Surface-enhanced Raman scattering (SERS) provides valuable information on the vibrational modes of molecules and the physical mechanism of surface plasmon resonance (SPR). In this paper we study the localized SPR process in Ag- or Ag/oxide-coated single-layer superaligned carbon nanotube (SACNT) films. Because of the unidirectional alignment of the carbon nanotubes in these films, the Raman signal is higher when the laser is polarized parallel to the aligned direction than when perpendicular to it. We investigated the polarization-dependent transmittance and Raman spectra for various Ag particle sizes and different oxide medium layers to study the localized SPR in these composite structures. These results systematically characterize the properties of SACNT film-based SERS substrates and clarify the origin of transmittance peaks

Thermoacoustic Chips with Carbon Nanotube Thin Yarn Arrays

Aligned carbon nanotube (CNT) films drawn from CNT arrays have shown the potential as thermoacoustic loudspeakers. CNT thermoacoustic chips with robust structures are proposed to promote the applications. The silicon-based chips can play sound and fascinating rhythms by feeding alternating currents and audio signal to the suspending CNT thin yarn arrays across grooves in them. In additional to the thin yarns, experiments further revealed more essential elements of the chips, the groove depth and the interdigital electrodes. The sound pressure depends on the depth of the grooves, and the thermal wavelength can be introduced to define the influence-free depth. The interdigital fingers can effectively reduce the driving voltage, making the chips safe and easy to use. The chips were successfully assembled into earphones and have been working stably for about one year. The thermoacoustic chips can find many applications in consumer electronics and possibly improve the audiovisual experience

Three-Dimensional Flexible Complementary Metal–Oxide–Semiconductor Logic Circuits Based On Two-Layer Stacks of Single-Walled Carbon Nanotube Networks

We have proposed and fabricated stable and repeatable, flexible, single-walled carbon nanotube (SWCNT) thin film transistor (TFT) complementary metal−oxide−semiconductor (CMOS) integrated circuits based on a three-dimensional (3D) structure. Two layers of SWCNT-TFT devices were stacked, where one layer served as n-type devices and the other one served as p-type devices. On the basis of this method, it is able to save at least half of the area required to construct an inverter and make large-scale and high-density integrated CMOS circuits easier to design and manufacture. The 3D flexible CMOS inverter gain can be as high as 40, and the total noise margin is more than 95%. Moreover, the input and output voltage of the inverter are exactly matched for cascading. 3D flexible CMOS NOR, NAND logic gates, and 15-stage ring oscillators were fabricated on PI substrates with high performance as well. Stable electrical properties of these circuits can be obtained with bending radii as small as 3.16 mm, which shows that such a 3D structure is a reliable architecture and suitable for carbon nanotube electrical applications in complex flexible and wearable electronic devices

The Dependence of Graphene Raman D‑band on Carrier Density

Raman spectroscopy has been an integral part of graphene research and can provide information about graphene structure, electronic characteristics, and electron–phonon interactions. In this study, the characteristics of the graphene Raman D-band, which vary with carrier density, are studied in detail, including the frequency, full width half-maximum, and intensity. We find the Raman D-band frequency increases for hole doping and decreases for electron doping. The Raman D-band intensity increases when the Fermi level approaches half of the excitation energy and is higher in the case of electron doping than that of hole doping. These variations can be explained by electron–phonon interaction theory and quantum interference between different Raman pathways in graphene. The intensity ratio of Raman D- and G-band, which is important for defects characterization in graphene, shows a strong dependence on carrier density

Additional file 1: Figure S1. of Dielectric-Like Behavior of Graphene in Au Plasmon Resonator

The absorption spectrum of single layer graphene. (JPG 132 kb

Additional file 2: Figure S2. of Dielectric-Like Behavior of Graphene in Au Plasmon Resonator

Confirmed by Raman spectrum. (JPG 191 kb

Load Characteristics of a Suspended Carbon Nanotube Film Heater and the Fabrication of a Fast-Response Thermochromic Display Prototype

The influence of heating load on the thermal response of a CNT film heater has been studied. Two kinds of heat dissipation modes, thermal radiation in a vacuum and convection in the atmosphere, are investigated, respectively. It is found that the thermal response slows down with the load quantities in the both cases. We have further studied the thermal response of a CNT film loaded with thermochromic pigment, which is a kind of phase change material. In addition to the thermal response slowing down with the load quantity, it is also found that the phase change of the thermochromic pigments can also slow down the thermal response. With a suspended CNT film heater structure, we have fabricated a thermochromic display prototype, which can switch from room temperature to 50 °C in about 1 s with a brightness contrast of 4.8 under normal indoor illumination. A 16 × 16 pixel thermochromic display prototype can dynamically display Chinese characters driven by a homemade circuit

Carbon Nanotube Film Gate in Vacuum Electronic Devices

A superaligned carbon nanotube (SACNT) film can act as an ideal gate electrode in vacuum electronics due to its low secondary electron emission, high electron transparency, ultrasmall thickness, highly uniform electric field, high melting point, and high mechanical strength. We used a SACNT film as the gate electrode in a thermionic emission electron tube and field emission display prototype. The SACNT film gate in a thermionic emission electron tube shows a larger amplification factor. A triode tube with the SACNT film gate is used in an audio amplification circuit. The SACNT film gate electrode in field emission devices shows better field uniformity. The field emission display prototype is demonstrated to dynamically display Chinese characters

Three-Dimensional Carbon Nanotube/Transition-Metal Oxide Sponges as Composite Electrodes with Enhanced Electrochemical Performance

Innovative three-dimensional (3D) carbon nanotube (CNT)/transition-metal oxide (TMO) sponge electrodes are synthesized by freeze-drying and calcination processes. The high specific surface area and porosity of the CNT sponge provide more attachment sites for the TMO nanoparticles, a larger contact area with electrolytes, and more space for volume expansion, which enable the CNT/TMO sponge electrodes to exhibit ultrahigh reversible capacity and excellent cycling stability. The continuous CNT network in this new type of electrode can fully satisfy fast electron-transfer kinetics; thus, excellent rate performance is realized. Furthermore, the unique structural characteristics of the 3D CNT sponge make it suitable for making almost all kinds of CNT/TMO composite electrodes, reflecting its versatility for use in many battery systems