Tunable photoluminescence in novel Ca2La1-xGdxNbO6:Bi3+ double perovskite phosphor for the application of luminescent cement-based composite materials

In this study, novel luminescent cement-based composite materials with tunable emission color were prepared. A series of novel Bi3+ doped double perovskite Ca2La1-xGdxNbO6 phosphors were firstly synthesized and the relationships between structure variation and tunable luminescence were discussed. The Gd substitution for La led to the change of crystal compressive strain, average bond length and polyhedron distortion of (Ca/Ln)O-6 polyhedron, which caused the emission color of Ca2La1-xGdxNbO6:Bi3+ tuned from (0.2020, 0.2472) to (0.1581, 0.0992). Furthermore, the synthesized Ca2La1-xGdxNbO6:Bi3+ phosphors were combined with cementitious materials, which made the luminescent specimens displayed tunable cyan-blue to blue emission color, and the XRD, SEM and EDS tests presented that the phosphors and cement were uniformly mixed in the cementitious material. These brilliant properties indicated that the synthesized phosphor could be used in exploring novel luminescent cement-based composite materials.