Doping of hydroxyapatite with europium ions Eu$^{3+}$ and investigation of the effect of codoping ions Dy$^{3+}$, Y$^{3+}$, B$^{3+}$ on its luminescent properties

Hydroxyapatite (HAP) was doped with europium Eu$^{3+}$ ions and the effect of doping Dy$^{3+}$, Y$^{3+}$ and B$^{3+}$ ions on its luminescent properties was studied in order to obtain hydroxyapatite with a high luminescence yield in the visible region of the spectrum. The photoluminescence spectra of codoped hydroxyapatites were studied: HAP:Eu,Dy, HAP:Eu,B, HAP:Eu,Y. It was found that codoping with Y$^{3+}$, B$^{3+}$ ions dramatically changes the HAP:Eu photoluminescence spectrum. In the spectra HAP:Eu,B and HAP:Eu,Y wide intense photoluminescence band appears with a maximum at the wavelengths $\lambda$ = 515 and 520 nm respectively, which is characteristic of europium ions Eu$^{2+}$.