Showing papers by "Claes-Göran Granqvist published in 2020"
TL;DR: In this paper, thin films of electrochromic (EC) W oxide were prepared by reactive DC magnetron sputtering and were immersed in electrolytes of LiClO4 in propylene carbonate with 0.5-3.0% of added polyethylene oxide (PEO).
9 citations
TL;DR: In this article, Tungsten-oxide-based thin films were prepared by reactive DC magnetron sputtering in the presence of oxygen and nitrogen, and the results showed that up to 4 at.% of nitrogen were as transparent as undoped tungsten oxide films and displayed enhanced electrochromic properties manifested in an increase in the coloration efficiency.
6 citations
5 citations
TL;DR: In this paper, the degradation of electrochromic W oxide and W-Ti oxide thin films, prepared by reactive DC magnetron sputtering, was studied by voltammetric cycling in potential intervals from 1.5-4.
Abstract: Electrochemical degradation of electrochromic W oxide and W-Ti oxide thin films, prepared by reactive DC magnetron sputtering, was studied by voltammetric cycling in potential intervals from 1.5-4. ...
5 citations
4 citations
TL;DR: In this article, a dual-target reactive DC magnetron sputtering was used to pre-process electrochromic W oxide and W-In oxide thin films and cycled voltammetrically in an electrolyte of lithium perchlorate in propylene carbonate.
3 citations
TL;DR: It is concluded that UV light activates the gas-sensing layer and improves gas detection at low concentrations of NO2, and the modulated sensor can replace an array of independent resistive sensors which would consume much more energy for heating.
Abstract: We present experimental results of fluctuation-enhanced gas sensing by low-cost resistive sensors made of a mixture of graphene flakes and TiO2 nanoparticles. Both components are photocatalytic and activated by UV light. Two UV LEDs of different wavelengths (362 and 394 nm) were applied to modulate the gas sensing of the layers. Resistance noise was recorded at low frequencies, between 8 Hz and 10 kHz. The sensors’ response was observed in an ambient atmosphere of synthetic air and toxic NO2 at selected concentrations (5, 10, and 15 ppm). We observed that flicker noise changed its frequency dependence at different UV light wavelengths, thereby providing additional information about the ambient atmosphere. The power spectral density changed by a few times as a result of UV light irradiation. The sensors were operated at 60 and 120°C, and the effect of UV light on gas sensing was most apparent at low operating temperature. We conclude that UV light activates the gas-sensing layer and improves gas detection at low concentrations of NO2. This result is desirable for the detection of the components of gas mixtures, and the modulated sensor can replace an array of independent resistive sensors which would consume much more energy for heating. We also suggest that a more advanced technology for preparing the gas-sensing layer, by use of spin coating, will produce corresponding layers with thickness of about a few μm, which is about ten times less than that for the tested samples. The effects induced by the applied UV light, having a penetration depth of only a few μm, would then be amplified.