Smart glass that could slash the cost of keeping buildings cool in summer has come a step closer.
Smart glass that could slash the cost of keeping buildings cool in summer has come a step closer following research into chemical vapour deposition (CVD) by UK chemists.
The glass functions by automatically filtering out warming rays from the sun. It is known that films of vanadium oxide react to a rise in temperature by undergoing a reversible semiconductor-metal phase transition, which is associated with a structural phase change from monoclinic to tetragonal. This leads to a significant increase in reflectivity to wavelengths of light in the infrared. The thermochromic phenomenon could potentially be harnessed to produce glass that automatically responds to a rise in temperature, blocking out incoming warmth. But the commercial viability of coating large areas of glass was unknown.
Researchers at the University of Salford, led by David Sheel and Martyn Pemble (who is now at the Tyndall National Institute in Ireland), together with Dimitra Vernadou, have demonstrated a commercially viable range of CVD regimes that allow deposition onto glass of doped films of vanadium oxide at the required thickness.
’In a commercial process, glass is coming off the production line in very large areas, 24 hours a day, seven days a week,’ Sheel told Chemistry World. ’Working with glass manufacturers, we have developed CVD technology that can be incorporated into this production system.’
The researchers, working on a project funded by the European Union, are confident that they will have produced a demonstration sample of glass with a thermochromic coating capable of being mass produced commercially in about 18 months time. Simon Hadlington