Red emitting K 2 NbF 7 :Mn 4+ and K 2 TaF 7 :Mn 4+ for warm-white LED applications Jansen, Thomas ; Baur, Florian ; Jüstel, Thomas Abstract Publication: Journal of Luminescence Pub Date: December 2017 DOI: 10.1016/j.jlumin.2017.07.061 Bibcode: 2017JLum..192..644J