Broadband, site selective and time resolved photoluminescence spectroscopic studies of finely size-modulated Y2O3:Eu3+ phosphors synthesized by a complex based precursor solution method

•Fine size tuning of cubic nano Y2O3:Eu3+ samples synthesized by a complex based precursor solution method.•Size tunning evidenced by broadening and shift of XRD and Raman scattering peaks.•No additional phases other than cubic have been detected neither with XRD nor with Raman scattering.•Electronic Raman scattering evidences the occupation of Eu ions substituting Y ions in S6 sites.•A progressive distortion of the C2 sites near the nanocrystal surface is evidenced by photoluminescence measurements.

Undoped and Eu3+-doped cubic yttria (Y2O3) nanophosphors of good crystallinity, with selective particle sizes ranging between 6 and 37 nm and showing narrow size distributions, have been synthesized by a complex-based precursor solution method. The systematic size tuning has been evidenced by transmission electron microscopy, X-ray diffraction, and Raman scattering measurements. Furthermore, size-modulated properties of Eu3+ ions have been correlated with the local structure of Eu3+ ion in different sized Y2O3:Eu3+ nanophosphors by means of steady-state and time-resolved site-selective laser spectroscopies. Time-resolved site-selective excitation measurements performed in the 7F0 → 5D0 peaks of the Eu3+ ions at C2 sites have allowed us to conclude that Eu3+ ions close to the nanocrystal surface experience a larger crystal field than those in the nanocrystal core. Under the site-selective excitation in the 7F0 → 5D0 peaks, energy transfer between the sites has also been observed.