Mika has a new publication about the energy storage properties of the Sr₃MgSi₂O₈:Eu²⁺,Dy³⁺ materials, take a look.

Lastusaari, M., Bos, A.J.J., Dorenbos, P., Laamanen, T., Malkamäki, M., Rodrigues, L.C.V. and Hölsä, J., Wavelength-sensitive energy storage in Sr₃MgSi₂O₈:Eu²⁺,Dy³⁺, J. Thermal Anal. Calorim. 121 (2015) 29-35.
Read online: http://dx.doi.org/10.1007/s10973-015-4571-7