Enhancement of luminescence of nanocrystalline TiO2:Yb3+ nanopowders due to co-doping with Nd3+ ions

• Homogeneous nanoparticles (∼10 nm) of TiO2:Yb and TiO2:Yb, Nd have been obtained.
• The Yb3+ and Nd3+ ions luminescence is observed when excited above the TiO2 band gap.
• The excitation energy transfer between Nd3+ and Yb3+ in TiO2 is observed.
• The temperature dependences of these excitation ways were determined from 4.5 K to 350 K.

This paper presents structural and luminescent properties of Yb doped and Yb–Nd double doped TiO2 nanopowders obtained by sol–gel method. Both, the morphology SEM-TE/TEM and structural XRD studies have revealed the presence of monodisperse nanoparticles with size of ∼10 nm. The obtained materials demonstrate the presence of Yb3+ and Nd3+ ions being found in luminescence when excited above the TiO2 band gap. Furthermore, the excitation energy transfer between Nd3+ and Yb3+ ions is observed. The temperature dependences of different excitation ways (via TiO2 host and via the energy transfer from Nd3+ to Yb3+) were established in the range from 4.5 K to 350 K. It was found that the TiO2:Yb(1.7%) Nd(0.2–2%) anatase nanopowders show significantly stronger luminescence than that of previously studied TiO2:Yb(1.7%) anatase/rutile material.