Near-infrared luminescence and quantum cutting mechanism in CaWO:Nd, Yb.

An efficient near-infrared (NIR) quantum cutting (QC) by converting ultraviolet into NIR via cooperative downconversion (DC) for the (Nd, Yb) couple in CaWO is studied since efficient two-step energy transfer occurs from the G level of Nd to two neighboring Yb:F level. The authors have analyzed the measured luminescence spectra and decay lifetimes for different Yb concentrations and proposed a mechanism to rationalize the DC effect. The maximum quantum efficiency (QE) of Nd is up to 164.03 %. Application of the broadband NIR-QC phosphors might enhance the performance of silicon-based solar cells. [ABSTRACT FROM AUTHOR]