Linear structural evolution induced tunable photoluminescence in clinopyroxene solid-solution phosphors

Clinopyroxenes along the Jervisite (NaScSi2O6) - Diopside (CaMgSi2O6) join have been studied, and a solid-solution of the type (Na1-xCax)(Sc1-xMgx)Si2O6 has been identified in the full range of 0 <= x <= 1. The powder X-ray patterns of all the phases indicate a structural similarity to the end compounds and show smooth variation of structural parameters with composition. The linear structural evolution of iso-structural (Na1-xCax)(Sc1-xMgx)Si2O6 solid-solutions obeying Vegard's rule has also been examined and verified by high resolution transmission electron microscopy (HRTEM). The continuous solid-solutions show the same structural type, therefore the photoluminescence spectra of Eu2+ doped samples possess the superposition of spectral features from blue-emitting component (CaMgSi2O6:Eu2+) and yellow-emitting one (NaScSi2O6:Eu2+). This indicates that the spectroscopic properties of (Na1-xCax)(Sc1-xMgx)Si2O6 clinopyroxene solid-solutions are in direct relations with structural parameters, and it is helpful for designing color-tunable photoluminescence with predetermined parameters.