Antireflective coatings on quartz glass for high temperature solar receivers

Within the Spanish DETECSOL project, antireflective (AR) coatings for quartz windows of solar tower receivers are developed for a more efficient solar thermal technology. The application of this coating on the window, similar to those applied on the glass envelopes of parabolic trough receivers, can decrease the optical losses and therefore increase the receiver efficiency. For these applications, not only the AR coating optical performance is important but also a high temperature and abrasion resistance. In this paper, a silica porous layer from a polymeric solution was prepared and deposited on both sides of a quartz window as an AR coating, increasing the solar transmittance from 0.931 to 0.975. The effect of increasing the heat treatment temperature to 500°C, 600°C and 700°C was studied. The coating thickness and/or the coating porosity decreased as the temperature increased. Moreover, we found that the coating abrasion resistance increased and the coating surface became more reactive as the treatment temperature increased.