Multilayer coatings D/M/D for solar reflector applications prepared by DC magnetron sputtering

Multilayer structures containing dielectric/ metal/ dielectric layers have been deposited on glass and coated with ITO substrates using DC magnetron sputtering technique. The multilayer coating based on interference effects can be realized by stacking metal (Ag) as a sandwich between two a high index dielectric (V2O5) i.e. V2O5/Ag/ V2O5.·V2O5 thin layers have been deposited using reactive DC magnetron sputtering technique from the sputtering of vanadium target in Ar/O2 mixture. X-ray diffraction (XRD) has been confirmed that the deposited thin layers are composed mainly of V2O5 phase. The reflectance spectra from visible to NIR wavelengths (300-1100) nm of multilayers were recorded. These thin layers were transparent for visible spectrum 400 - 800 nm however reflecting IR radiations beyond 800 nm. The optical measurements for all the thin layers samples that were prepared, which based on V2O5/Ag/V2O5 multilayers structure with varying thickness 20,40,60,80 nm of top layer for V2O5 while 10,20 nm of middle layer (Ag) and bottom layer (V2O5) respectively. Result shows that, the ITO single and V2O5 (20nm) / Ag (10nm)/V2O5 (40nm) multilayer gave maximum transmittance about 92.4 % at 550 nm. Also NIR reflection of the multilayer coating is less than 10% in the VIS range and it enhanced to over 80% in the NIR range of V2O5 20nm)/Ag (10nm)/V2O5 (20nm) multilayer. The best performance was accomplished for the heat mirror with 10 nm of Ag thickness and 20nm of outer layer of V2O5.