CHARACTERISTICS OF METAL CHALCOGENIDE SOLAR CONTROL FILMS WITH A PROTECTIVE POLYMER COATING

CuxS, PbS-CuxS and PbS solar control films deposited on glass substrates by a chemical deposition technique require a transparent polymer coating, primarily to offer protection during window cleaning. In this article we look into the extent of the modification introduced by such a coating in the values of the integrated transmittance T*(VIS), T*(IR) and T*(SOL) in the visible, the IR and the entire solar (air mass 2) spectral range and the integrated reflectance R(f)*(VIS) and R(s)*(VIS) for the film side and substrate side of these glazings. The T*(SOL) values of CuxS and PbS-CuxS coated glazings have been found to increase by 2%-3% but, in the case of PbS-coated glazings, this increment is up to 6%. In the case of R(f)*(VIS) and R(s)*(VIS), there is generally a decrease in the values after the protective coating is applied, which helps to reduce the glare problems and imaging effects. While these modifications may be considered as minimal, the masking of low emissivities (about 0.5) of the CuxS and PbS-CuxS films due to the polymer coating is a drawback since it increases the thermal re-radiation into the interior.