Incorporation of Zn2+ ions into Al2O3:Er3+/Yb3+ transparent ceramics: An effective way to enhance upconversion and near infrared emission

Al 2 O 3 : Er 3+ /Yb 3+ transparent ceramics codoped with Zn 2+ ions with intense upconversion and near infrared emission were prepared by conventional solid-state reaction and vacuum and hot isostatic pressing sintering. The effects of Zn 2+ incorporation to the structure, transparent, upconversion and NIR luminescence were discussed in detail. The as prepared Al 2 O 3 ceramics exhibited a total transmittance of ~ 75% in infrared regions (800–3300 nm) and ~ 50% in visible regions (500–800 nm). Under the excitation of a 980 nm laser diode , the as prepared Al 2 O 3 ceramics displayed two tense upconversion emission peaks of a green one centered at 550 nm and a red one centered at 660 nm and a tense near infrared emission peak centered at 1.532 µm, characteristic of Er 3+ emission. Compared with Er 3+ /Yb 3+ doped only, Zn 2+ codoped Al 2 O 3 :Er 3+ /Yb 3+ transparent ceramics showed higher upconversion and near infrared emission of ~ 11 times and ~ 4 times, respectively. The enhancement mechanism due to incorporation of Zn 2+ ions was also discussed in detail.