scispace - formally typeset
Search or ask a question

Showing papers by "Claes-Göran Granqvist published in 2005"


Journal ArticleDOI
TL;DR: This study clearly indicates that metals indeed have varying thrombogenic and complement activating properties, and these studies have implications for the selection of metals intended for medical applications.

76 citations


Journal ArticleDOI
TL;DR: In this paper, the electrical and optical properties of In2O3:Sn (indium tin oxide; ITO) nanoparticles were investigated in porous thin films consisting of ITO nanoparticles.
Abstract: Electrical and optical properties were investigated in porous thin films consisting of In2O3:Sn (indium tin oxide; ITO) nanoparticles. The temperature-dependent resistivity was successfully described by a fluctuation-induced tunneling model, indicating a sample morphology dominated by clusters of ITO nanoparticles separated by insulating barriers. An effective-medium model, including the effect of ionized impurity scattering, was successfully fitted to measured reflectance and transmittance. Post-deposition treatments were carried out at 773 K for 2 h in both air and vacuum. It is shown that vacuum annealing increases either the barrier width or the area between two conducting clusters in the samples and, furthermore, an extra optical absorption occurs close to the band gap. A subsequent air annealing then reduces the effect of the barriers on the electrical properties and diminishes the absorption close to the band gap.

48 citations


Journal ArticleDOI
TL;DR: In this article, anomalies in atomic force microscopy (AFM) based size determination of nanoparticles via comparative analysis of experiments and numerical calculations were studied via comparative analyses of experiments.
Abstract: Anomalies in atomic force microscopy (AFM) based size determination of nanoparticles were studied via comparative analysis of experiments and numerical calculations. Single tungsten oxide nanoparticles with a mean diameter of $3\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ were deposited on mica and graphite substrates and were characterised by AFM. The size (height) of the nanoparticles, measured by tapping mode AFM, was found to be sensitive to the free amplitude of the oscillating tip, thus indicating that the images were not purely topographical. By comparing the experimental results to model calculations, we demonstrate that the dependence of the nanoparticle size on the oscillation amplitude of the tip is an inherent characteristic of the tapping mode AFM; it is also a function of physical properties such as elasticity and surface energy of the nanoparticle and the sample surface, and it depends on the radius of curvature of the tip. We show that good approximation of the real size can easily be obtained from plots of particle height vs free amplitude of the oscillating tip, although errors might persist for individual experiments. The results are valid for size (height) determination of any nanometer-sized objects imaged by tapping mode AFM.

37 citations


Journal ArticleDOI
TL;DR: Tungsten oxide nanoparticles were generated by excimer (ArF) laser assisted chemical vapor deposition from WF6/H2/O2/Ar gas mixtures as discussed by the authors.

13 citations


Journal ArticleDOI
TL;DR: In this paper, photoacoustic and thermal lens spectroscopy was used to study four different semiconductor samples: PbI2, 4HSiC, NiCrO and NiO.
Abstract: In this work we used photoacoustic and thermal lens spectroscopy to study four different semiconductor samples: PbI2, 4HSiC, NiCrO and NiO. The results showed that the combination of these two tech ...

3 citations


Proceedings ArticleDOI
03 Aug 2005
TL;DR: In this paper, the authors discuss a number of aspects of a novel flexible electrochromic foil capable of varying its optical transmittance and present a detailed model for the coloration/bleaching due to proton extraction/insertion in thin surface sheaths of nanocrystallites of nickel oxide.
Abstract: We discuss a number of aspects of a novel flexible electrochromic foil capable of varying its optical transmittance. The foil includes thin films of tungsten oxide and nickel oxide laminated together by a polymer electrolyte. Starting with scientific issues, we discuss the dominating defects in amorphous tungsten oxide and how they may yield a consistent picture of the optical properties of tungsten oxide films versus nonstoichiometry and ion intercalation. We also present a detailed model for the coloration/bleaching due to proton extraction/insertion in thin surface sheaths of nanocrystallites of nickel oxide. Next we consider aspects of technology and treat options to enhance the bleached-state transmittance by mixing the nickel oxide with another oxide having a wide band gap. We also cover pre-assembly charge insertion/extraction by facile gas treatments of the films as well as practical device manufacturing. The final part of the paper deals with a number of applications , with emphasis on architectural "smart windows" which can improve indoor comfort at the same time as they accomplish significant energy savings due to lowered requirements for air cooling. Applications concerning electrochromics-based eyewear are introduced; these may be approaching market introduction.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

3 citations


Proceedings ArticleDOI
17 Nov 2005
TL;DR: A new technology, called SEPTIC, SEnsing of Phage‐Triggered Ion Cascade, based on using noise analysis to detect the massive ionic fluxes associated with the initial step of bacteriophage infection, the injection of the phage DNA into the cell is introduced and tested.
Abstract: A rapid, inexpensive and specific identification of arbitrary bacteria under field conditions is urgently needed. To this end, we have introduced and tested a new technology, called SEPTIC, SEnsing of Phage‐Triggered Ion Cascade. In its prototype form based on a nanowell chip, SEPTIC has already been shown to be capable of unambiguous identification of live bacteria on a time scale of seconds to minutes, many times faster than any other system. The technology is based on using noise analysis to detect the massive ionic fluxes associated with the initial step of bacteriophage infection, the injection of the phage DNA into the cell. Here we show the results and pose a number of unsolved problems of noise. Ultimately, sensors based on this new technology would be able to save many lifes.

3 citations


01 Jan 2005
TL;DR: In this paper, the electrical and optical properties of In2O3:Sn (indium tin oxide; ITO) nanoparticles were investigated in porous thin films consisting of ITO nanoparticles.
Abstract: Electrical and optical properties were investigated in porous thin films consisting of In2O3:Sn (indium tin oxide; ITO) nanoparticles. The temperature-dependent resistivity was successfully described by a fluctuation-induced tunneling model, indicating a sample morphology dominated by clusters of ITO nanoparticles separated by insulating barriers. An effective-medium model, including the effect of ionized impurity scattering, was successfully fitted to measured reflectance and transmittance. Post-deposition treatments were carried out at 773 K for 2 h in both air and vacuum. It is shown that vacuum annealing increases either the barrier width or the area between two conducting clusters in the samples and, furthermore, an extra optical absorption occurs close to the band gap. A subsequent air annealing then reduces the effect of the barriers on the electrical properties and diminishes the absorption close to the band gap.