Photon upconversion of Nd³⁺–Yb³⁺–Tb³⁺ doped core–shell–shell–shell nanoparticles

Abstract

The NaYF 4 :Yb migration layer minimized the cross-relaxation. Excited energy absorbed by Nd 3+ could sensitize the co-doped Yb 3+ and activated Tb 3+ though energy migration among Yb 3+ , thereby achieving luminescence of Tb 3+ .