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 …