Extraction-Pyrolytic Synthesis and Luminescent Properties of Borates La0.95Eu0.05BO3 : Sm and La0.95Eu0.05(BO2)3 : Sm

Abstract

Orthoborates La0.95–хEu0.05SmхBO3 and metaborates La0.95 – хEu0.05Smх(BO2)3 (х = 0.025, 0.05, 0.075, 0.1) have been obtained under optimal conditions by extraction-pyrolytic method at lower temperature and shorter time as compared with the known methods. Increase in Sm3+ ion concentration leads to decrease of unit cell volume in La0.95 – хEu0.05SmхBO3 (aragonite structural type) and La0.95 – хEu0.05Smх(BO2)3 (monoclinic modification of α type). The larges changes in luminescence excitation spectra of the compounds depending on Sm3+ concentration is observed in 360–450 nm region, which includes the bands of transitions for both Eu3+ and Sm3+ ions. On luminescence excitation in the band of maximal absorption of Sm3+ ion (λeх = 404 nm), luminescence intensity of cooperatively doped La0.925Eu0.05Sm0.025(BO2)3 and La0.925Eu0.05Sm0.025BO3 increases, which can be explained by the possibility of efficient transfer of absorbed energy from Sm3+ to Eu3+ ion.