Gentle, A, Tai, M, White, S, Arnold, M, Cortie, M & Smith, G 2018, 'Design, control, and characterisation of switchable radiative cooling', Proc. SPIE 10759, New Concepts in Solar and Thermal Radiation Conversion and Reliability, 107590L, SPIE Optics + Photonics 2018, SPIE, USA.View/Download from: UTS OPUS or Publisher's site
© 2018 SPIE. Here we present our recent developments in temperature dependent ellipsometry, FTIR and emittance measurements of flat and structured vanadium dioxide (VO2) surfaces allowing significant control of switchable radiative cooling beyond that attainable via traditional VO2 surfaces. VO2 undergoes a metal-insulator transition at a critical temperature of ∼ 68°C; previous work has investigated tuning of this critical temperature over a wide range of temperatures. Here we exploit the shift in optical properties to produce surfaces with various emittance temperature profiles that modulate the thermal radiative transfer to/from a surface. Designing surfaces with different temperature emittance profiles requires accurate optical/thermal characterisation of materials. VO2 is produced by sputtering of vanadium followed by post deposition annealing in a 0.1Torr to 0.3Torr Air atmosphere at 450°C to 550°C, in-situ optical monitoring allows for accurate termination of the annealing process once the desired optical response is achieved.