Achieving a Cr6+-free Cr3+-activated spinel phosphor by a one-step solid-state reaction

Co-doping of Bi 3+ into the spinel ZnAl 2 O 4 reduces the density of anti-site defects and further inhibits the formation of the Cr( vi ) impurity, leading to a Cr 6+ -free Cr 3+ -activated ZnAl 2 O 4 :Cr 3+ ,Bi 3+ phosphor.