Infrared emissivities of Mn, Co co-doped ZnO powders

Infrared emissivities of Zn_0.99-xMn_0.01Co_xO (x=0.00, 0.01, 0.03, 0.05) powders synthesized at different calcination temperatures by solid-state reaction are investigated. Their phases, morphologies, UV absorption spectra, and infrared emissivities are studied by XRD, SEM, UV spectrophotometer, and IR-2 Dual-Band Infrared Emissometer in a range of 8 μm-14 μm. Doped ZnO is still of wurtzite structure, and no peaks of other phases originating from impurities are detected. The optical band-gap decreases as the Co content and calcination temperature ascend, and of which the smallest optical band-gap is 2.19 eV. The lowest infrared emissivity, 0.754, is observed in Zn_0.98Mn_0.01Co_0.01O with the increase in Co concentration. The infrared emissivity experiences fluctuations with calcination temperature going up, and its minimum value is 0.762 at 1100℃.