The codoping of ${\mathrm{CaF}}_2:{\mathrm{Pr}}^{3+}$ with ${\mathrm{Yb}}^{3+}$ ions is shown to lead to the formation of ${\mathrm{Pr}}^{3+}/{\mathrm{Yb}}^{3+}$ clusters, which can be attractive quantum cutting systems to enhance solar cells’ efficiency. Very high ${\mathrm{Pr}}^{3+}$ to ${\mathrm{Yb}}^{3+}$ energy transfer efficiencies (ETEs) are achieved for low ${\mathrm{Yb}}^{3+}$ and ${\mathrm{Pr}}^{3+}$ concentrations ( $\mathrm{ETE}=97\%$ in ${\mathrm{CaF}}_2:0.5\%{\mathrm{Pr}}^{3+}\text{-}1\%{\mathrm{Yb}}^{3+}$ ) confirming the short distance between ${\mathrm{Pr}}^{3+}$ and ${\mathrm{Yb}}^{3+}$ ions within clusters. A low ${\mathrm{Yb}}^{3+}$ concentration offers the advantage of drastically limiting the ${\mathrm{Yb}}^{3+}$ concentration quenching usually observed in other hosts where the ${\mathrm{Yb}}^{3+}$ concentration has to be larger to achieve a high ETE for solar cell applications.