Phosphorene Nanoribbon-Augmented Optoelectronics for Enhanced Hole Extraction.

Phosphorene nanoribbons (PNRs) have been widely predicted to exhibit a range of superlative functional properties; however, because they have only recently been isolated, these properties are yet to be shown to translate to improved performance in any application. PNRs show particular promise for optoelectronics, given their predicted high exciton binding energies, tunable bandgaps, and ultrahigh hole mobilities. Here, we verify the theorized enhanced hole mobility in both solar cells and space-charge-limited-current devices, demonstrating the potential for PNRs improving hole extraction in universal optoelectronic applications.

Fitting Single-Walled Carbon Nanotube Optical Spectra.

In this work, a comprehensive methodology for the fitting of single-walled carbon nanotube absorption spectra is presented. Different approaches to background subtraction, choice of line profile, and calculation of full width at half-maximum are discussed both in the context of previous literature and the contemporary understanding of carbon nanotube photophysics. The fitting is improved by the inclusion of exciton-phonon sidebands, and new techniques to improve the individualization of overlapped nanotube spectra by exploiting correlations between the first- and second-order optical transitions and the exciton-phonon sidebands are presented.

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube-silicon solar cells.

Recent results in the field of carbon nanotube-silicon solar cells have suggested that the best performance is obtained when the nanotube film provides good coverage of the silicon surface and when the nanotubes in the film are aligned parallel to the surface. The recently developed process of dry shear aligning - in which shear force is applied to the surface of carbon nanotube thin films in the dry state, has been shown to yield nanotube films that are very flat and in which the surface nanotubes are very well aligned in the direction of shear. It is thus reasonable to expect that nanotube films subjected to dry shear aligning should outperform otherwise identical films formed by other processes.

Aligned Carbon Nanotube Thin Films from Liquid Crystal Polyelectrolyte Inks.

Single walled carbon nanotube thin films are fabricated by solution shearing from high concentration sodium nanotubide polyelectrolyte inks. The solutions are produced by simple stirring of the nanotubes with elemental sodium in dimethylacetamide, and the nanotubes are thus not subject to any sonication-induced damage. At such elevated concentrations (∼4 mg mL(-1)), the solutions exist in the liquid crystal phase and during deposition this order is transferred to the films, which are well aligned in the direction of shear with a 2D nematic order parameter of ∼0.

A TiO2 Nanofiber-Carbon Nanotube-Composite Photoanode for Improved Efficiency in Dye-Sensitized Solar Cells.

A light-scattering layer fabricated from electrospun titanium dioxide nanofibers (TiO2 -NFs) and single-walled carbon nanotubes (SWCNTs) formed a fiber-based photoanode. The nanocomposite scattering layer had a lawn-like structure and integration of carbon nanotubes into the NF photoanodes increased the power conversion efficiency from 2.9 % to 4.

Double-walled carbon nanotube processing.

Single-walled carbon nanotubes (SWCNTs) have been the focus of intense research, and the body of literature continues to grow exponentially, despite more than two decades having passed since the first reports. As well as extensive studies of the fundamental properties, this has seen SWCNTs used in a plethora of applications as far ranging as microelectronics, energy storage, solar cells, and sensors, to cancer treatment, drug delivery, and neuronal interfaces. On the other hand, the properties and applications of double-walled carbon nanotubes (DWCNTs) have remained relatively under-explored.

Sorting of Double-Walled Carbon Nanotubes According to Their Outer Wall Electronic Type via a Gel Permeation Method.

In this work, we demonstrate the application of the gel permeation technique to the sorting of double-walled carbon nanotubes (DWCNTs) according to their outer wall electronic type. Our method uses Sephacryl S-200 gel and yields sorted fractions of DWCNTs with impurities removed and highly enriched in nanotubes with either metallic (M) or semiconducting (S) outer walls. The prepared fractions are fully characterized using optical absorption spectroscopy, transmission electron microscopy, and atomic force microscopy, and the entire procedure is monitored in real time using process Raman analysis.

Effect of Nanotube Film Thickness on the Performance of Nanotube-Silicon Hybrid Solar Cells.

The results of measurements on solar cells made from randomly aligned thin films of single walled carbon nanotubes (SWCNTs) on -type monocrystalline silicon are presented. The films are made by vacuum filtration from aqueous TritonX-100 suspensions of large diameter arc-discharge SWCNTs. The dependence of the solar cell performance on the thickness of the SWCNT film is shown in detail, as is the variation in performance due to doping of the SWCNT film with SOCl₂.

Single-walled carbon nanotube/polyaniline/n-silicon solar cells: fabrication, characterization, and performance measurements.

Carbon nanotube-silicon solar cells are a recently investigated photovoltaic architecture with demonstrated high efficiencies. Silicon solar-cell devices fabricated with a thin film of conductive polymer (polyaniline) have been reported, but these devices can suffer from poor performance due to the limited lateral current-carrying capacity of thin polymer films. Herein, hybrid solar-cell devices of a thin film of polyaniline deposited on silicon and covered by a single-walled carbon nanotube film are fabricated and characterized.

High-order graphene oxide nanoarchitectures.

We fabricate unique photoluminescent three dimensional graphene oxide (GO) architectures, so-called GO flowers, by self-assembly onto silicon substrates via solvent-mediated volume-controlled growth. The GO flowers exhibited bright photoluminescence and a photoresponse demonstrating their potential for advanced optical and electronic applications, such as advanced photovoltaic devices and organic light emitting diodes.