Structural insights on Li+ doped P6̄ crystals of upconverting NaYF4:Yb3+/M3+ (M3+ = Er3+ or Tm3+) through extensive synchrotron radiation-based X-ray probing

Intensification of upconversion luminescence (UCL) from a single phase NIR-upconverting (UC) crystal due to perturbation of the local symmetry field may not always manifest through average structural attributes like lattice parameters.