¹⁵¹Eu-MOSSBAUER SPECTRA AND XPS INVESTIGATION OF BaFBr: Eu PHOSPHOR

¹⁵¹Eu Mossbauer spectra of BaFBr:Eu phosphor are reported for the first time.The results show that f(Eu₂₊)<f(Eu₃₊) or <x²>Fu²⁺><x²>Fu³⁺,which indicates that the attraction between phonons and Eu²⁺ is stronger than that between phonons and Eu³⁺,this may cause a faster increase of f(Eu²⁺) vs f(Eu³⁺) when temperature decreases as observed in the experiments.It is also found from Mossbauer investigation that when temperature decreases,the relative content of Eu²⁺ decreases, while that of Eu³⁺ increases.The temperature dependent Mossbauer spectra provide evidence for electron exchange or hopping between Eu²⁺ or Eu³⁺ sites in BaFBr lattice. The Mossbauer results are discussed and compared with the results of XPS and Photoluminescence studies.