Engineering near-infrared emitting scintillators with efficient Eu2+ → Sm2+ energy transfer

Recently, we proposed a concept for a new class of near infrared (NIR) scintillators by employing efficient Eu2+ → Sm2+ energy transfer. In this article we investigate the optical spectroscopy of Sm2+ in BaBrI, CsSrI3, and CsBa2I5 halide hosts. A criterion was derived for fast Sm2+ 5d → 4f emission and a list of new potential NIR scintillators is proposed.