Inhibiting emission quenching in (Y0.1Yb0.05Er0.005Al)2O3 by Sc3+ co-doping to enhance upconversion luminescence

► Sc3+ co-doped (Y0.1Yb0.05Er0.005Al)2O3 was synthesized for the first time. ► The co-doped Sc3+ acted as a quenching inhibitor by adjusting the microstructure. ► The up-conversion luminescence was enhanced remarkably as a result. ► The research may be useful for designing and synthesis of other up-conversion materials.