Erbium Doping Effects on the Structural and Infrared Luminescence Properties of Gd2Ti2O7 Nanocrystals

Er3+ (0.1, 1, 5, 10, 15, or 20 mol%)-doped Gd2Ti2O7 nanocrystals were fabricated by the sol-gel method. While annealing temperature reaches 800 degrees C, amorphous phase transfers to well-crystallized ErxGd2-xTi2O7 pyrochlore nanocrystals. The average crystal size increases from similar to 70 to similar to 600 nm under 800 to 1200 degrees C/1 h annealing. Because of the fast Er-Er energy transfer, all of the Stokes photoluminescence (PL) (I-4(13/2) -> I-4(15/2) transition, similar to 1534 nm) decay curves are single-exponential for samples with 0.1-20 mol% Er3+ doping concentrations annealed at 1100 degrees C/1 h. The Gd2Ti2O7 nanocrystals with 10 mol% Er3+ doping concentration (1.56 x 10(21) ions/cm(3)) annealed at 1100 degrees C/1 h possess the maximum PL intensity, 77 nm full width at half maximum (FWHM) of the PL spectrum, and longest lifetime (9.52 ms). However, Er3+ (20 mol%)-doped Gd2Ti2O7 nanocrystals annealed at 1100 degrees C/1 h exhibit the weaker PL intensity, wider FWHM of the PL spectrum (109 nm), and shortest lifetime (2.46 ms) due to the concentration quenching effect. (C) 2013 The Electrochemical Society. All rights reserved.