Structure twinning, electronic and photoluminescence properties of yavapaiite-type orthophosphate BaTi(PO4)2

For the first time, the detailed crystal structure of BaTi(PO4)2 was studied by a non-merohedral twinning model. Theoretical studies show that it has direct optical transitions which can be assigned to the charge transfer from O-2p to Ti-3d states. The photoluminescence emission ranging from 400 nm to 700 nm is originated from the self-trapped exaction recombination.238