High pressure luminescence of InNbO4:Eu3+: A crystal-field analysis

InNbO4 and InNbO4:Eu3+ phosphors were synthesized by solid-state reaction method. The structural stability and crystal field under high pressure are investigated up to 34.5 GPa using in-situ Raman and luminescence spectra. The evolution of Raman and luminescence spectra with pressure of InNbO4 revealed one reversible phase transition at around 12 GPa. A progressive red shift and luminescence quenching were observed for InNbO4:Eu3+ phosphors during compression. The pressure-induced variation of local environment and crystal field around Eu3+ ions was analyzed using Judd–Ofelt (J-O) intensity parameter Ω2. Both the parameter Ω2 and luminescence property were indicative of a pressure-induced lower asymmetry around Eu3+ sites in InNbO4. These results suggest that the pressure has a great influence on fluorescence intensity and energy levels of Eu3+ ions.