Spectroscopic and structural properties of polycrystalline Y2Si2O7 doped with Er3

Abstract Powders of yttrium disilicate (Y 2 Si 2 O 7 ) doped with Er 3+ have been prepared by the sol–gel method. The structure of the obtained powders has been determined. Room temperature emission spectra have been recorded and excited state decay profiles have been analyzed. Differences between the spectroscopic properties of Er 3+ in monoclinic α-Y 2 Si 2 O 7 (space group P-1) and β-Y 2 Si 2 O 7 (space group C2/m) polymorphs have been investigated and shown. The significant broadening of the emission spectra recorded for the α phase compared to the one for the β phase was discussed in terms of higher number of Y 3+ sites (4) present in the α phase with respect to only one Y 3+ site in the case of β phase. The higher value of the luminescence decay time of β phase (11.2 ms) compared to the α phase (8.5 ms) is associated with the higher site symmetry of β-Y 2 Si 2 O 7 . Moreover it was found that Er 3+ concentration affects the shape of the 4 I 13/2 → 4 I 15/2 emission band. It results in changes of the relative emission intensities of peaks localized at 1527 nm and 1532 nm; this indicates changes of the Y 3+ sites occupation on increasing the Er 3+ concentration. The luminescence lifetime was observed to decrease with the increase of Er 3+ concentration. The spectroscopic results have been compared with the ones relative to thin films of Y 2 Si 2 O 7 :Er 3+ with a similar composition. The lower value of the luminescence decay time observed for thin films compared to the powder of α phase was explained with the changes of the particles packing resulting in the change of the effective refractive index.