Synthesis and characterization of neodymium doped yttrium molybdate high NIR reflective nano pigments

• High NIR reflecting nano pigments Y6−xNdxMoO12 were synthesized by sol–gel.
• The pigments crystallized completely at 900 °C with particle size less than 100 nm.
• The doping of Nd3+ changed the pigments color from yellow to yellow-green.
• The pigment Y5.2Nd0.8MoO12 exhibited the optimum NIR solar reflectance of 89.9%.

High near-infrared reflecting nano pigments Y6−xNdxMoO12 (x ranges from 0 to 1.0) based on yttrium molybdate doped with Nd3+ were synthesized by sol–gel. The pigments samples were characterized by means of TG-DTA, FTIR, XRD, SEM, UV–vis–NIR spectrophotometer and CIE L∗a∗b∗ color measurement. The results showed that the pigments crystallized completely at 900 °C with particle size less than 100 nm. The substitution of Nd3+ for Y3+ in Y6MoO12 induced the absorption in the region of 585–605 nm and as a result the color changed from yellow to yellow-green. The near-infrared reflectance and solar reflectance increased first and then decreased with increasing Nd3+ content. When x = 0.8, the pigment exhibited an optimum NIR solar reflectance of 89.9%. The thermal and chemical stability of the pigments was also evaluated.