Energy transfer based efficient infrared emission at 1.57 μm from Yb3+–Er3+ codoped Zinc-borobismuthate glasses

An intense NIR emission at 1.57 μm is reported in a newly synthesized Yb3+–Er3+ codoped Zinc-borobismuthate glasses. The energy transfer efficiency is found to be 78% for 1 mol% Yb2O3 and 0.5 mol% Er2O3 concentrations. The transfer process follows a static energy transfer mechanism at a low donor concentration (0.1 mol%); whereas, it gets accelerated by donor energy migration at 1 mol% Yb2O3. In this glass system, the energy back-transfer has found to be negligible from estimated critical interaction distances for direct (Yb3+ → Er3+) and back (Yb3+ ← Er3+) energy transfer phenomena. The observed efficient NIR emission at 1.57 μm has been explained based on the effective energy transfer from Yb3+ ions accompanied by rapid depopulation of 4I11/2 excited level of Er3+ ions through non-radiative multi-phonon relaxation processes, which has also restricted the excited state absorption (ESA) from this level leading to no upconversion suggesting the potentiality of present glass host for proficient NIR luminescence.

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► Efficient emission at 1.57 μm from Yb3+–Er3+ codoped Zinc borobismuthate glasses with 78% energy transfer efficiency.
► Negligible probability for energy back-transfer in present glasses.
► Strong non-radiative relaxation from 4I11/2 to 4I13/2 of Er3+ ions through multi-phonon process restricted the upconversion.