Rare-earth-free luminescent non-stoichiometric phases formed in SrO–HfO2 ternary compositions

•Three stable non-stoichiometric phases in SrO–HfO2 sintered mixtures determined.•Relation between XRPD analyses and radioluminescence spectra studied.•Highly efficient radioluminescence of Sr0.98Hf1.02O3.02 phase revealed.•Nature of emission centers in non-stoichiometric phases discussed.

Non-stoichiometric strontium hafnate powder samples were prepared by reaction in solid state using the starting SrO–HfO2 mixture with different ratios of binary constituents. XRD analysis was systematically performed and correlated with the observed radioluminescence characteristics. In the samples with starting surplus of HfO2 a Sr0.98Hf1.02O3.02 phase was identified which is associated with the 334 nm emission band. Its radioluminescence intensity exceeds more than thirty times that of bismuth germanate (BGO) standard single crystal scintillator. In the samples with initial surplus of SrO, two different Sr-rich phases were identified in the sintered material. Their radioluminescence spectra peak within 420–430 nm and intensities are comparable to that of BGO.