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This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (http://creativecommons.org/licenses/by/3.0/), Organic–inorganic halides based perovskite solar cells (PSCs) have attracted a great deal of attention from the photovoltaic (PV) research community due to the extremely rapid increases in efficiencies observed over the past few years. The PSC is an extension of dye-sensitised solar cells and has reached an energy conversion efficiency of 19.3% by mid-2014. However, PSCs do have some disadvantages such as use of expensive metal electrodes, the high temperature required during production and poor stability when in use. There is no doubt that research with carbon nanomaterials will play an important role in understanding and solving the issues currently observed in PSCs, as they consistently have been shown to improve performance in a wide range of energy related applications. The present review (i) provides a brief introduction to PSC development; (ii) highlights the notable achievements of PSCs; (iii) particularly focuses on the use of nanocarbon in mesoscopic PSCs and (iv) predicts and suggests a roadmap for the future application of carbon materials in this emerging technology

In this work a simple and up-scalable technique for creating arrays of high purity carbon nanotubes via plasma enhanced chemical vapor deposition is demonstrated. Inductively coupled plasma enhanced chemical vapor deposition was used with methane and argon mixtures to grow arrays in a repeatable and controllable way. Changing the growth conditions such as temperature and growth time led to a transition between single and multi-walled carbon nanotubes and was investigated. This transition from single to multi-walled carbon nanotubes is attributed to a decrease in catalytic activity with time due to amorphous carbon deposition combined with a higher susceptibility of single-walled nanotubes to plasma etching. Patterning of these arrays was achieved by physical masking during the iron catalyst deposition process. The low growth pressure of 100 mTorr and lack of reducing gas such as ammonia or hydrogen or alumina supporting layer further show this to be a simple yet versatile procedure. These arrays were then characterized using scanning electron microscopy, Raman spectroscopy and x-ray photoelectron spectroscopy. It was also observed that at high temperature (550 °C) single-walled nanotube growth was preferential while lower temperatures (450 °C) produced mainly multi-walled arrays.

A new working electrode for dye solar cells has been fabricated incorporating an array of dye sensitised single walled carbon nanotubes on an indium tin oxide coated glass substrate as a replacement for the titania used in conventional dye solar cells.

We report upon the pressure driven water transport through porous silicon (pSi) and single walled carbon nanotube (SWCNT) membranes. Fabrication of the membranes was monitored by AFM and SEM. Water permeability as high as 16926 mm3 cm-2 s-1 atm-1 is found for the pSi membrane. The SWCNT membrane is built upon the pSi membrane and a water permeability of 0.02 mm3 cm-2 s-1 atm-1 is achieved. Performance comparisons to similar CNT membranes are made and future improvements to the system are proposed.

A vertically aligned nanotube (NT) array platform with peptide-modified ends is used for sensing metal ions in aqueous environments. The NT arrays were assembled on gold substrates and characterised using confocal Raman microscopy to confirm the electrode fabrication process. A copper ion selective peptide - GlyGlyHis - was used as the sensing recognition element. Cyclic voltammetry was used to measure the sensor's electrochemical response of the bound copper and to determine the stability of the sensor. The sensor showed minimum interference from other species and was proven to be very sensitive, enabling detection in the nanomolar range.

Vertically-aligned arrays of single walled carbon nanotubes were created on an optically transparent electrode (FTO glass) these arrays were found to exhibit a prompt current and voltage when exposed to light. These cells were then investigated by electrochemical impedance spectroscopy and found to exhibit a dampening of the recombination reaction over the first 24 hours. Symmetrical cell modeling was successful in simulating the behavior of normal cell architecture.

Substrates with four different nanotube modifications have been prepared and their electron transport properties measured. Two modification techniques were compared; covalent chemical attachment of both single and multi-walled carbon nanotubes to transparent conductive (fluorine doped tin oxide) glass surfaces and chemical vapour deposition (CVD) growth of both single and multi-walled carbon nanotubes on highly doped conductive silicon wafers. These carbon nanotube modified substrates were investigated using scanning electron microscopy and substrates with nanotubes grown via CVD have a much higher density of nanotubes than substrates prepared using chemical attachment. Raman spectroscopy was used to verify that nanotube growth or attachment was successful. The covalent chemical attachment of nanotubes was found to increase substrate electron transfer substantially compared to that observed for the bare substrate. Nanotube growth also enhanced substrate conductivity but the effect is smaller than that observed for covalent attachment, despite a lower nanotube density in the attachment case. In both modification techniques, attachment and growth, single-walled carbon nanotubes were found to have superior electron transfer properties. Finally, solar cells were constructed from the nanotube modified substrates and the photoresponse from the different substrates was compared showing that chemically attached single-walled nanotubes led to the highest power generation. © 2012 Elsevier Ltd. All rights reserved. Refereed/Peer-reviewed

Single-molecule surface-enhanced Raman scattering (SM-SERS) utilizes localized surface plasmons in metallic nanostructures for enhanced signal detection. This work demonstrates the use of SM-SERS on an electrochemically anodized biocompatible nanoporous gold (NpAu) substrate using a bi-analyte Raman technique. It was found that the positions (so-called hot-spots) with the closest etched valley widths (w), or the smallest w/valley wall width (D) (ligaments), of the Au nanopores dominated the Raman scattering. By using an etched substrate with a w < 10 nm and a w/D < 0.2 an estimated enhancement factor of 107 for both Nile blue and Rhodamine 6G dyes was achieved. Importantly, the bi-analyte Raman technique enabled the clear confirmation of single (or few) molecule detection on the Np/Au substrates. Refereed/Peer-reviewed

Here we report on the production of an Ag2SO4/Ag2O mixed-grain powder during the anodization of Ag foil in a HF-H2SO4 electrolyte. We propose that there are three competing reactions during the anodization process: (i) the production of Ag2O at the Ag foil anode surface from the presence of water in the electrolyte, (ii) the dissolution of the Ag2O in the presence of HF releasing Ag+ ions, (iii) the precipitation of Ag+ and SO4 2− ions, as Ag2SO4 on the Ag foil anode surface. This co-precipitation/dissolution process ultimately results in a mixed-grain powder. We then show that the Ag2O embedded within the mixedgrain is photo-decomposed to produce highly fluorescent silver nanoclusters (Agn) which decorate the Ag2SO4 crystals. The Ag2SO4 salt offers a stable matrix for the photo-decomposed Agn nanoclusters to emit their strong fluorescence. Refereed/Peer-reviewed

This study presents a simple approach to perform selective mass transport through freestanding porous silicon (pSi) membranes. pSi membranes were fabricated by the electrochemical etching of silicon to produce membranes with controlled structure and pore sizes close to molecular dimensions (∼12 nm in diameter). While these membranes are capable of size-exclusion based separations, chemically specific filtration remains a great challenge especially in the biomedical field. Herein, we investigate the transport properties of chemically functionalized pSi membranes. The membranes were functionalized using silanes (heptadecafluoro-1,1,2,2-tetrahydrodecyl)dimethylchlorosilane (PFDS) and N-(triethoxysilylpropyl)-o-polyethylene oxide urethane (PEGS) to give membranes hydrophobic (PFDS) and hydrophilic (PEGS) properties. The transport of probe dyes tris(2,2′-bipyridyl)dichlororuthenium(ii) hexahydrate (Rubpy) and Rose Bengal (RB) through these functionalized membranes was examined to determine the effect surface functionalization has on the selectivity and separation ability of pSi membranes. This study provides the basis for further investigation into more sophisticated surface functionalization and coupled with the biocompatibility of pSi will lead to new advances in membrane based bio-separations. Refereed/Peer-reviewed

Single-walled carbon nanotubes (SWNTs) were chemically attached to an n-type silicon (100) substrate (n-Si) by exposing the surface to a nanotube-containing suspension for attachment times varying from 2 to 72 h. The SWNTs were imaged by atomic force microscopy (AFM) revealing a high density of vertically aligned SWNT bundles. Cyclic voltammetry experiments demonstrated that the n-type character of the substrate was maintained after the chemical attachment process. The SWNT/n-Si surfaces were found to field emit with a turn-on field ranging from 1.37-1.64 V m-1. From the Fowler-Nordheim (F-N) plots the field enhancement factor, β, was found to vary between ∼5000-7000 depending upon attachment time, which is consistent with changes in the sharpness of the SWNT tips as shown by AFM. The robustness of the field emitters was tested by maintaining a constant current and measuring the change in voltage required. The structures were found to have excellent stability over several days. The prospect for chemically attached SWNT arrays in field emission displays is discussed. © 2008 The Royal Society of Chemistry. Refereed/Peer-reviewed