Hydrothermal trivalent lanthanide doped Lu2O3 nanorods: Evaluation of the influence of the surface in optical emission properties

► Hydrothermal synthesis of lanthanide (Ln) doped Lu2O3 nanorods of 90 nm of diameter. ► Measured lifetimes of Tm3+3H4, 3F4 multiplets similar to those in Lu2O3 single crystals. ► Strong upconverted red 4F9/2 → 4I15/2 emission of Er3+ in Yb3+-codoped Lu2O3 nanorods. ► Very reduced slopes in log plots of the upconversion intensity vs. excitation power. ► Changes in Ln3+ emission dynamics associated to surface adsorbed high energy phonons.