Claes-Göran Granqvist

Bio: Claes-Göran Granqvist is an academic researcher from Uppsala University. The author has contributed to research in topics: Electrochromism & Thin film. The author has an hindex of 73, co-authored 535 publications receiving 31523 citations. Previous affiliations of Claes-Göran Granqvist include Chalmers University of Technology & Texas A&M University.

Low-refractive-index indium-tin-oxyfluoride thin films made by high-rate reactive dc magnetron sputtering.

Abstract: Indium–tin–oxyfluoride (ITOF) films were prepared by dc magnetron sputtering of indium–tin in Ar + O2 + CF4. Spectrophotometric measurements in the 0.2–2.5-μm wavelength range were used to evaluate the dielectric function. Wide band gap ITOF, with a refractive index of ~1.5 in the visible and good durability, was produced at a rate of ~1.2 nms−1. ITOF is well suited for antireflecting transparent and conducting indium–tin–oxide coatings.

Critical Remarks on Landauer's principle of erasure-dissipation

Abstract: We briefly address Landauer's Principle and some related issues in thermal demons. We show that an error-free Turing computer works in the zero-entropy limit, which proves Landauer's derivation incorrect. To have a physical logic gate, memory or information-engine, a few essential components necessary for the operation of these devices are often neglected, such as various aspects of control, damping and the fluctuation-dissipation theorem. We also point out that bit erasure is typically not needed or used for the functioning of computers or engines (except for secure erasure).

Thermochromics for Energy Efficient Buildings: Thin Surface Coatings and Nanoparticle Composites

Abstract: This chapter outlines the state of the art of the thermochromic glazings that are able to provide energy efficiency by letting in more solar energy at a low temperature than at a high temperature, thereby leading to diminished need for space cooling. Thermochromic technology employs VO2-based materials as thin coatings or nanoparticle composites. For coatings, suitable switching between conditions with high and low solar energy throughput at low and high temperature, respectively, can be achieved by replacing some of the vanadium atoms by tungsten, and luminous transmittance can be enhanced by the addition of some magnesium. Antireflection (AR) coatings can give further improvements. By going to nanoparticle composites with VO2 dispersed in a transparent host, it is possible to combine high luminous transmittance with large modulation of solar energy transmittance. This modulation ensues from plasmonic absorption in metallic-like VO2 nanoparticles. Thermochromic glazings are not yet (2015) available as products, but the rapid development during recent years has led to performance limits that appear very interesting for practical applications. Energy modeling of buildings with thermochromic glazings points at very substantial savings. A further development may be to integrate thermochromic nanoparticles in laminated electrochromic devices.

Graphene photonics and optoelectronics

Abstract: The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential lies in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultrawideband tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light-emitting devices to touch screens, photodetectors and ultrafast lasers. Here we review the state-of-the-art in this emerging field.