Upconversion studies on Yb3+/Er3+ doped CeO2 and CeF3 phosphors: Enhanced near infrared emission

• Good visible upconversion emission in CeO2: Er3+/Yb3+ phosphor on 980 nm excitation.
• No visible upconversion in CeF3: Er3+/Yb3+ phosphor.
• Strong emission at 1530 nm in case of CeF3: Er3+/Yb3+ phosphor.
• Host composition is found to play a role in upconversion emission mechanism.

Upconversion emission in CeF3: Er3+/Yb3+ and CeO2: Er3+/Yb3+ phosphors is studied using 976 nm diode laser excitation and the emission results are compared. The Ce3+ ion is found to interact with Er3+ ion that enhances the energy transfer rate among the levels of Er3+ ion. The increased energy transfer rate enables increase in the infrared emission (∼1530 nm) at the expense of visible upconversion emission. An intense emission at ∼1530 nm due to the 4I13/2→4I15/2 transition of Er3+ ion, with least emission in the UV/visible region, is observed in the CeF3: Er3+/Yb3+ phosphor. The emission intensity of 4I13/2→4I15/2 transition is also compared for LaF3, CeF3 and LaF3 hosts and it is found that the emission intensity is maximum for CeF3 host. The CeF3: Er3+/Yb3+ phosphor is found suitable for optical amplifiers, laser materials and infrared imaging probes around 1530 nm.