Synthesis and characterization of a new high NIR reflective ytterbium molybdenum oxide and related doped pigments. (March 2017)

• Record Type: Journal Article
• Authors: Schildhammer, Daniel; Fuhrmann, Gerda; Petschnig, Lucas; Weinberger, Nikolaus; Schottenberger, Herwig; Huppertz, Hubert
• Is Part Of: Dyes and pigments. Volume 138(2017)
• Page Start: 90
• Page End: 99
• Publication Date: 2017-03
• Subjects: Rare earth molybdenum oxides -- Near-infrared reflectance -- Inorganic pigments -- Brick-red-yellow pigments -- Cool pigments; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2016.11.024
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: A novel yellow NIR reflecting pigment with the formula Yb6 Mo2 O15 crystallizing in a trigonal structure with the color coordinates L* = 88.7, a* = −6.6, b* = 55.0, C* = 55.4, and h° = 96.8 is described. Color variation from pale yellow to brick-red was realized by partial substitution of Yb 3+ or Mo 6+ with various metal ions. The novel pigments of the formula Yb6−x D x Mo2 O15±δ ( D = Na, Ca, Ti, Bi) and Yb6 Mo2−x M x O15−δ ( M = Na, Fe, Co, Nb, Bi) were characterized by powder XRD and UV–Vis-NIR diffuse reflectance spectroscopy. The high NIR solar reflectance of Yb6 Mo2 O15 of 93.7% (PTFE used as reference) was further improved with Yb5.4 Ti0.6 Mo2 O15+δ and Yb6 NbMoO15−δ reaching values of 99.4%, and 99.7%, respectively. Finally, the potential of the new rare earth molybdenum oxides for use as cool pigments in rooftop applications was demonstrated by the developed brick-red compound Yb6 Mo1.6 Fe0.4 O15−δ having an enlarged band gap of 2.46 eV in comparison to 2.3 eV for Yb6 Mo2 O15 . Furthermore, Yb6 Mo1.6 Fe0.4 O15−δ exhibits an impressive NIR reflectivity of 90.4%.