Spectroscopic, vibrational and structural insights into LaYbO3:Pr3+ and LaLuO3:Pr3+,Tb3+ perovskites at ambient and high-pressure conditions

The interlanthanide perovskites LaYbO 3 :Pr 3+ and LaLuO 3 :Pr 3+ ,Tb 3+ were synthesized by a solid-state reaction and characterized at ambient conditions by means of X-ray diffraction (XRD), Raman spectroscopy and photoluminescence techniques. XRD measurements have shown that the synthesis method provided samples with pure perovskite phase (space group Pnma ) for LaYbO 3 , while in the case of the LaLuO 3 compound small traces of Lu 2 O 3 could be found after several annealing. Up to 13 Raman active modes were observed in the Raman spectra of the studied perovskites and theoretical calculations performed for LaYbO 3 allowed to assign their symmetry. Regarding their optical properties, the emission from Tb 3+ ions at B sites of the AB O 3 perovskite could be distinguished. Moreover, NIR emission from Pr 3+ was observed in the LaLuO 3 perovskite at ∼1000 nm and 1250–1600 nm. Emission in these spectral regions could be relevant for Si-based solar cell applications and fiber optic amplifiers, respectively. Moreover, the stability of both perovskites under high-pressure conditions has been studied spectroscopically, finding that LaYbO 3 is stable up to 19 GPa and that LaLuO 3 undergoes a possible pressure-induced phase transition at ∼21–24 GPa. This makes LaLuO 3 the first interlanthanide perovskite showing phase transition under 40 GPa.