Adamantane‐Type Nitridophosphate Phosphors AExLi10–2xP4N10:Eu2+via Medium‐Pressure Ion‐Exchange Reactions

Nitridophosphates have emerged as promising host compounds in the field of solid‐state lighting. Their industrial relevance has increased significantly, mainly due to recent advances in synthetic approaches under medium‐pressure (MP) conditions, including ammonothermal synthesis and hot isostatic pressing (HIP). In this study, we report on the synthesis and characterization of the quaternary representatives CaxLi10–2xP4N10 (x = 2, 2.7, 4) and Sr3Li4P4N10, prepared via a simplified ion exchange reaction under MP conditions, starting from the nitridophosphate‐based lithium ion conductor Li10P4N10. The synthesis route allowed for the preservation of the anionic [P4N10]10– structural motif of the starting material, while simultaneously introducing potential doping sites for Eu2+ by incorporating divalent alkaline earth cations (Ca2+/Sr2+). Upon excitation of Eu2+ doped samples with blue light, strong luminescence due to parity‐allowed 4f6(7F)5d1→4f7(8S7/2) transition can be observed in the red (Ca2Li6P4N10:Eu2+: λmax = 626 nm), yellow/orange (Ca2.7Li4.6P4N10:Eu2+: λmax1 = 506 nm, λmax2 = 592 nm and Sr3Li4P4N10:Eu2+: λmax = 596 nm) and green (Ca4Li2P4N10:Eu2+: λmax = 546 nm) spectral regions of the visible light. The compounds presented, together with the simplified synthetic approach, demonstrate the significant potential of ion exchange on Li ion conductors for the development of novel nitridophosphates in the future.