Cu1.5Mn1.5O4-based ceramic spectrally selective coatings for efficient solar absorber applications

Cu1.5Mn1.5O4-based ceramic spectrally selective (CSS) coating was deposited on aluminum substrate using a sol-gel dip-coating method. The citric acid introduced in the precursor system lowered the required calcining temperature of crystalline Cu1.5Mn1.5O4. X-Ray diffraction (XRD) peaks of coatings annealed above 450 °C were found to coincide exactly with that of crystalline Cu1.5Mn1.5O4 in JCPDS database. By optimizing the withdrawal rate and calcining temperature, coating with spectral selectivity as good as αs = 0.876 and ε100 = 0.057 was achieved after only one dipping/annealing cycle. Subjected to an accelerated ageing test at 259 °C, the obtained CSS coating showed an excellent thermally durability with the performance criterion (PC) values below 0.05.