Near infrared-emitting Er- and Yb-Er- doped CeF3 nanoparticles with no visible upconversion.

In this work, a host which interacts and enhanced energy transfer to the luminescent center such that it facilitates the infrared emission while avoiding undesired emissions was found. An intense emission at approximately 1530 nm with no other visible emissions was observed in Er- and Yb-Er- doped CeF3 nanoparticles upon excitation at approximately 975 nm. The average measured luminescence lifetimes of the approximately 1530 nm emission for heat-treated CeF3:Er and CeF3:Yb,Er nanoparticles was approximately 4.5-6.5 ms, with internal quantum efficiencies up to approximately 52-75%. These nanoparticles offer a vast range of potential applications, which include optical amplifiers, waveguides, laser materials and infrared imaging probes.