Robust Yellow-Violet Pigments Tuned by Site-Selective Manganese Chromophores

Abstract

The rational design of multifunctional inorganic pigments relies on the manipulation of ionic valence and local surroundings of a chromophore in structurally and chemically habitable hosts. To date, the development of environmentally benign and intense violet/purple pigments is still a challenge. Here we report a family of A_3-xMn_xTeO₆ and A_3-2xMn_xLi_xTeO₆ (A = Zn, Mg; x = 0.01-0.15) pigments colored by site-selective Mn²⁺O₄ yellow and Mn³⁺O_5-6 violet chromophores. Zn_2.9Mn_0.1TeO₆ is intense bright yellow, comparable with commercial BiVO₄, and has better near-infrared reflectivity (∼89%) in comparison to commercial TiO₂. The codoped Li⁺ "activator" generates holes and charge-balanced Mn³⁺ (Mn³⁺O_5-6), realizing a color transformation from yellow to the bright violet pigments of A_3-2xMn_xLi_xTeO₆. The most vivid Mg_2.8Mn_0.1Li_0.1TeO₆ is probably the best violet pigment known to date, exhibits excellent chemical and thermodynamic stability, and demonstrates pressure-dependent stability up to 5-7 GPa, before a (reversible) phase transition to pink. Theoretical calculations revealed the correlation between site-preference occupancy and chromophore motifs and predicted a wide color gamut of pigments in Zn₃TeO₆-hosted 3d transition-metal ions other than manganese.