1 23 Journal of Materials Science: Materials in Electronics ISSN 0957-4522 Volume 26 Number 9 J Mater Sci: Mater Electron (2015) 26:6667-6675 DOI 10.1007/s10854-015-3268-9 Structural and photoluminescence studies of Co 2+ doped Ca–Li hydroxyapatite nanopowders K. Ravindranadh, B. Babu, M. C. Rao, Jaesool Shim, Ch. Venkata Reddy & R. V. S. S. N. Ravikumar