A comparative study on different RE-doped (RE=Pr, Nd, Sm) SrCuSi4O10 blue pigments with high near-infrared reflectance

Ecological inorganic blue pigments Sr1-xRExCuSi4O10+δ (RE = Pr, Nd, Sm, x ranges from 0 to 0.5) with high near-infrared reflectance were synthesized via sol-gel method. The pigments were characterized with scanning electron microscopy, UV-vis-NIR diffuse reflectance spectroscopy and the Commission Internationale de l'Eclairage 1976 L*a*b* colorimetric method. After annealed at 900 °C, the SrCuSi4O10 pigment samples exhibited near-infrared solar reflectance of 62.64% and relative intense blue color. The near-infrared reflectance spectra of different rare earth ions doped SrCuSi4O10 pigments presented various fluctuations due to the configurational electric dipole transitions. The incorporation of rare earth ions can promote the near-infrared reflectance and solar reflectance of SrCuSi4O10 pigments. When the adding amount of Pr, Nd and Sm, was 20%, 40% and 10%, the near-infrared solar reflectance of SrCuSi4O10 pigments reached the optimal value of 72.00%, 68.54%, 68.67%, respectively, which are expected to be promising candidates as environmentally benign cool blue pigments.