“…Various activators, including Eu 2+ , Dy 3+ , Er 3+ , Tb 3+ , and Nd 3+ , have been used as doping agents to obtain the desired luminescence property [9][10][11][12]. Moreover, transition metal ions, including Mn 2+ , Ni 2+ , Cu 2+ , and Zn 2+ , have been incorporated for enhancing luminescence intensity [13].…”