Luminescence properties of Ca2Sn2Al2O9: Mn as a long afterglow and field-emission displays material with high yellow color purity

Abstract In this work, a series of rare earth free orange phosphors Ca2Sn2Al2O9: Mn (CSA: Mn) are synthesized successfully by two-steps high temperature solid-state reaction. Their crystal structure and luminescence properties are studied detail. CSA is a typical orthorhombic crystal system and belonging to P b c n (60) space group. There is only one kind Ca2+ site with seven coordinations in the structure for Mn2+ occupying. This phosphor possesses self-emitting and self-reduction due to the defects carrying negative charge which can provide electrons for Sn4+ and Mn4+. When Sn4+ and Mn4+ get electrons, they will generate their characteristic low valence electron transfer (Sn2+ and Mn2+) and emit relative radiation transition. The host emission yielding from Sn2+ and the broad orange emission from Mn2+ has an apparent energy transfer because of their overlap of the luminescence spectra. Furthermore, CSA: Mn2+ possesses orange PL emission with long afterglow about 7 h after 10 min UV excitation due to the defects' trap energy level. And, Mn2+’s temperature dependent photoluminescence intensity appeared anomalous phenomena that the intensity increases firstly and then decreases, which is due to the traps energy level's contribution of electron's transition. Besides, CSA: Mn2+ can emit bright orange light under cathode ray and it has very stable CL properties after suffering long time electron beam bombarding. CSA: Mn2+ is a kind potential application value material in long afterglow and FED.