“…It was reported that the XPS peak positions of Sr 3d shifted to the higher-energy side upon oxidation. 25,26,28 This is due to the greater electronegativity of oxygen. So in our case, Sr 3d 3/2 can be further deconvoluted into Sr-O (3d 3/2 ) and Sr-N (3d 3/2 ) at B136.12 and B135.13 eV, respectively, and Sr 3d 5/2 into Sr-O (3d 5/2 ) and Sr-N (3d 5/2 ) at B134.32 and B133.31 eV, respectively.…”