Pressure-induced dark-to-bright transition inLu2O3:Ce

Application of pressure to the nonemitting system ${\mathrm{Lu}}_{2}{\mathrm{O}}_{3}:{\mathrm{Ce}}^{3+}$ leads to the generation of luminescence in the visible. The luminescence is assigned to the $5\stackrel{\ensuremath{\rightarrow}}{d}4f$ transition of ${\mathrm{Ce}}^{3+},$ and is attributed to a pressure-induced electronic crossover of the excited $5d$ state of ${\mathrm{Ce}}^{3+}$ and the conduction-band edge of ${\mathrm{Lu}}_{2}{\mathrm{O}}_{3}.$ The results yield insight into the emission efficiency of $5\stackrel{\ensuremath{\rightarrow}}{d}4f$ transitions, and provide a foundation for advancing new phosphors and tunable laser materials in the visible and ultraviolet based on the broad $5\stackrel{\ensuremath{\rightarrow}}{d}4f$ emission of lanthanides.