One-Dimensional Titanium Dioxide Nanomaterials: Nanowires, Nanorods, and Nanobelts

Review of physical vapor deposited (PVD) spectrally selective coatings for mid- and high-temperature solar thermal applications

Nanoceramic VO2 thermochromic smart glass: A review on progress in solution processing

Spectrally selective solar absorbers harvest solar energy in the form of heat. Solar absorbers using cermet-based coatings demonstrate a high absorptance of the solar spectrum and a low emittance in the infrared (IR) regime. Extensive work has been done to optimize cermet-based solar absorbers to achieve high performance by exploring different cermet (ceramic–metal composite) materials and film configurations through different preparation techniques such as electrodeposition, sputtering, pulsed laser deposition, and solution-based methods. In this article, we review the progress of cermet-based spectrally selective absorbers with high solar absorptance and low thermal emittance, such as Cr2O3, Al2O3, AlN, SiO2, and ZrO2 based cermets as absorption layers. We also present an outlook for cermet-based spectrally selective absorbers with high thermal stability and high conversion efficiency from sunlight to heat.

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A review of cermet-based spectrally selective solar absorbers

A significant amount of energy is consumed to maintain thermal comfort in buildings, a huge portion of which is lost through windows. Smart coating, thin films with spectrally selective properties on the surface of glass, is the innovative solution to the problem. Thermochromic smart windows change their color and optical properties in response to temperature variations. The performance, materials, coating technologies and energy modeling of thermochromic windows are reviewed in the present study. The effect of doping vanadium dioxide (VO2) coatings with different dopants such as tungsten, fluorine, gold nanoparticles and etc. is elaborated. Various deposition techniques, specifically hybrid chemical vapor deposition (AA/APCVD) and physical vapor deposition (PVD) methods are elucidated. Different dopants and techniques show different results on metal to semiconductor transition (MST) and the critical temperature. The “change in visible and infra-red transmission and reflectance” is the touchstone of performance for the different afforded chromogenic intelligent windows.

Performance, materials and coating technologies of thermochromic thin films on smart windows

Al3+-doped vanadium dioxide thin films deposited by PLD

An easy process was developed to synthesize TiO2 nanowires sensitized with CdS and CdTeS quantum dots (QDs) requiring no pretreatment of the TiO2 nanowires prior to nanoparticle generation. CdS and CdTeS nanoparticles were firstly grown by an in situ colloidal method directly onto the TiO2 surface, hence not requiring subsequent functionalization of the QDs. The resulting nanostructure assembly and composition was confirmed by transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Successful decoration of the TiO2 nanowires by the QDs was observed by TEM, while XPS spectra provided clear evidence for the coexistence of CdS and CdTeS QDs and TiO2 nanowires. The electronic structure of the TiO2 nanowires was preserved as indicated by Raman spectroscopy. Preliminary photocurrent measurements showed that inclusion of Te in CdS QDs improved the photocurrent efficiency. Compared to bare TiO2 nanowires, CdS/TiO2 nanoassemblies showed an enhancement in photocurrent efficiency of 300% while CdTeS/TiO2 presented an improvement of 350%. This study indicates that the generation of strongly anchored CdS and CdTeS QDs on a TiO2 nanowire surface is achievable without introduction of a linker molecule, whose presence is known to decrease the electron injection efficiency.

http://iopscience.iop.org/article/10.1088/0957-4484/22/6/065603/pdf

CdS and CdTeS quantum dot decorated TiO2 nanowires. Synthesis and photoefficiency.

Optical and structural properties of pulsed laser deposited Ti:Al2O3 thin films

An easy process was developed to fabricate TiO 2 nanowires sensitized with CdS and CdTeS quantum dots (QDs). CdS
and CdTeS nanoparticles were grown in situ by a colloidal method. No pretreatment of the TiO 2 nanowires was required
prior to nanoparticle generation. Functionalization of CdS and CdTeS QDs was not needed to anchor these nanoparticles
to TiO 2 surface. The resulting nanostructure assembly and composition was confirmed by transmission electron
microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The electronic structure of TiO 2 nanowires was
preserved as indicated by Raman spectroscopy. The sensitization of the TiO 2 nanowires by the QDs was confirmed by
photocurrent measurements. This study allows the generation of strongly anchored CdS and CdTeS QDs on TiO 2 
nanowires surface without the introduction of a linker molecule which presence decreases the electron injection
efficiency.

Bo Chen

Papers

Al3+-doped vanadium dioxide thin films deposited by PLD

CdS and CdTeS quantum dot decorated TiO2 nanowires. Synthesis and photoefficiency.

Optical and structural properties of pulsed laser deposited Ti:Al2O3 thin films

Nanoassemblies for photovoltaic applications