Near-infrared luminescence of manganate(V)-doped phosphates and vanadates

Abstract Manganese(V) is stabilized in various phosphate and vanadate lattices with apatite and spodiosite structure on quasi-tetrahedral sites. At all temperatures between 10 and 298 K the luminescence spectra consist of sharp lines in the near infrared, assigned to 1 E → 3 A 2 (T d ). The observed splitting Δ E between the two low-symmetry orbital components of the emitting state 1 E(T d ) is correlated with structural distortion data of the (PO 4 ) 3- and (VO 4 ) 3- tetrahedra in the host. Luminescence lifetimes of Mn 5+ in five different compounds vary between 300 and 700 μs at 10 K. At room-temperature lifetimes are reduced by factors of 1.4 to 11, depending on the host lattices.