Co-doping Sm3+ transforms Y2Ge2O7:Pr3+ into a novel orange-reddish long afterglow phosphor

Red long afterglow phosphors have significant implications for the realization of multicolor long-afterglow phosphors, but their insufficient luminescence intensity and afterglow duration still cannot meet the demands of practical applications. In this study, a novel orange-red phosphor, Y2Ge2O7:Pr3+, was synthesized for the first time. This phosphor not only exhibits exceptional thermal resistance but also shows a marked enhancement in long-afterglow performance upon co-doping with Sm3+. Remarkably, an orange-red afterglow can still be distinctly observed with the naked eye even 5 min after the removal of the excitation source in darkness. Further investigations involving thermoluminescence spectrum tests and the construction of an independent host-referred binding energy (HRBE) diagram reveal that the introduction of Sm3+ effectively mitigates the trap depth (1.02 eV) of the Y2Ge2O7:Pr3+ phosphor and significantly augments the quantity of electrons in shallow traps. This modification facilitates the effective release of electrons under room temperature conditions by the improved phosphor, thereby actualizing the long-afterglow luminescence phenomenon. Additionally, our findings indicate that a trap depth within the range of 0.60–0.80 eV is the optimal range for releasing electrons at room temperature. This research offers a crucial reference for future endeavors aimed at enhancing the performance of long-afterglow phosphors. •A novel orange-red long afterglow phosphor, Y2Ge2O7:Pr3+, Sm3+, was successfully synthesized using the high-temperature solid-state method.•Co-doping with Sm3+ successfully reduces the trap depth of Y2Ge2O7:Pr3+, increases the number of electrons in shallow traps, and exhibits long afterglow luminescence.•Both YGO:Pr3+ and YGO:Pr3+, Sm3+ phosphors exhibit excellent thermal stability, indicating potential application value in information storage.