Search results for " THIN FILMS"

Thermochromic Thin Films: Synthesis, Properties and Energy Consumption Modelling

2013

Thermochromic materials such as vanadium dioxide have been postulated for use in “SMART” windows for a number of years. Such windows work by exploiting a structural phase change from an infra-red transmissive state to a infra-red reflective state. Significant challenges still remain before such materials will be able to find wide spread use. In this mini review we discuss the nature of this thermochromic transition with reference to the latest research work in the field. We pay particular attention to challenges such as film colouration, transition temperature, and transition hysteresis. We describe the most up to date strategies for addressing these challenges, considering advanced synthes…

Nanostructured materials for solar cells: electrochemical fabrication and characterization

2011

The origin of slow electron recombination processes in dye-sensitized solar cells with alumina barrier coatings

2004

We investigate the effect of a thin alumina coating of nanocrystalline TiO2 films on recombination dynamics of dye-sensitized solar cells. Both coated and uncoated cells were measured by a combination of techniques: transient absorption spectroscopy, electrochemical impedance spectroscopy, and open-circuit voltage decay. It is found that the alumina barrier reduces the recombination of photoinjected electrons to both dye cations and the oxidized redox couple. It is proposed that this observed retardation can be attributed primarily to two effects: almost complete passivation of surface trap states in TiO2 that are able to inject electrons to acceptor species, and slowing down by a factor of…

Self-organization and nanostructural control in thin film heterojunctions.

2013

In spite of more than two-decades of studies of molecular self-assembly, the achievement of low cost, easy-to-implement and multi-parameter bottom-up approaches to address the supramolecular morphology in three-dimensional (3D) systems is still missing. In the particular case of molecular thin films, the 3D nanoscale morphology and function are crucial for both fundamental and applied research. Here we show how it is possible to tune the 3D film structure (domain size, branching, etc.) of thin film heterojunctions with nanoscale accuracy together with the modulation of their optoelectronic properties by employing an easy two-step approach. At first we prepared multi-planar heterojunctions w…

Suspended single-electron transistors: Fabrication and measurement

2005

We have fabricated aluminum single-electron transistors in which the island is not in contact with the substrate. This new type of device, which can be called suspended single-electron transistor (SUSET), displayed well-defined I-V and dI/dV-V features typical for high-quality standard SET's.

A facile semi-open method for synthesis of non-centrosymmetric superconducting Li2(Pd,Pt)3B bulks and thin films

2010

Abstract Non-centrosymmetric superconductor Li 2 (Pd 1− x Pt x ) 3 B, x  = 0–1 was synthesized from mixtures of the elements. A simple semi-open method is proposed using endings-pressed stainless steel tubes placed in a high-vacuum furnace. Heating regime employed a short-time overheating at 900 °C and a slow cooling step between T s and 550 °C within 3 h. To adequately compensate Li-losses and attain maximum critical temperature, the optimum T s and starting Li-content were found to change from 720 to 740 °C and from Li 2.4 to Li 2.6 , respectively, when x was changing from 0 to 1. It was shown that placing Li separately in the tube also produces superconducting samples, Li being supplied …

Preparation of photocatalytic nanostructured TiO2 thin films

2008

Micro/nanostructured thin films : synthesis by ALD of composites associating TiO2 inverse opals and gold nanoparticles for photocatalysis applications

2021

The aim of this work was to improve the photocatalytic properties of titanium dioxide (TiO2) thin films, a semiconductor that is widely used for photocatalysis applications, particularly for the treatment of polluted water. For this purpose, two complementary approaches were studied: increasing the surface area available for photocalatytic reactions and coupling between TiO2 and gold nanoparticles.. For the first approach, TiO2 thin films with different morphological structures were fabricated by Atomic Layer Deposition: dense and porous flat films, and inverse opals films.In order to evaluate photocatalytic activity of the different films, the degradation of methylene blue in aqueous solut…

Monolayer and multilayer field-effect transistors based on a high-mobility n-type polymer: effect of the polymeric texture on charge transport

2012

Spin and charge currents driven by the Higgs mode in high-field superconductors

2020

The Higgs mode in superconducting materials describes slowly decaying oscillations of the order parameter amplitude. We demonstrate that in superconductors with a built-in spin-splitting field the Higgs mode is strongly coupled to the spin degrees of freedom, allowing for the generation of time-dependent spin currents. Converting such spin currents to electric signals by spin-filtering elements provides a tool for the second-harmonic generation and the electrical detection of the Higgs mode generated by the external irradiation. The nonadiabatic spin torques generated by these spin currents allow for the magnetic detection of the Higgs mode by measuring the precession of the magnetic moment…