This work reports the synthesis, structural characterization, and optical properties of ZrO2:Yb3+-Er3+ (2–1 mol%) nanocrystals. The nanoparticles were coated with 3-aminopropyl triethoxysilane (APTES) and further modified with biomolecules, such as Biotin-Anti-rabbit (mouse IgG) and rabbit antibody-AntiKi-67, through a conjugation method. The conjugation was successfully confirmed by Fourier transform infrared, zeta potential, and dynamic light scattering. The internalization of the conjugated nanoparticles in human cervical cancer (HeLa) cells was followed by two-photon confocal microscopy. The ZrO2:Yb3+-Er3+ nanocrystals exhibited strong red emission under 970-nm excitation. Moreover, the luminescence change due to the addition of APTES molecules and biomolecules on the nanocrystals was also studied. These results demonstrate that ZrO2:Yb3+-Er3+ nanocrystals can be successfully functionalized with biomolecules to develop platforms for biolabeling and bioimaging.
This work presents the structural, morphological and luminescent properties of Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>:Ce<sup>3+</sup>(0.1%)-Pr<sup>3+</sup>(0.1%)
nanophosphors synthesized by a hydrothermal precipitation method. It was observed that the incorporation of Amonium
hydroxide (NH<sub>4</sub>OH, Ammonia) increases the YAG (%)/YAM(%) ratio, leading to an increase of 83% in the overall
emission under 460 nm excitation. The nanophosphor with the highest content of YAM, presented the best broad green-yellow-
red emission band corresponding to Ce<sup>3+</sup> and Pr<sup>3+</sup> emissions under 340 nm excitation. The average
nanocrystallite size was 50 and 55 nm for the samples with and without Ammonia respectively. Quenching of the overall
emission after an annealing treatment at 1100°C is observed in spite of reaching single YAG crystalline phase. That
suggests Pr<sup>4+</sup> and/or color centers formation due to the estequiometric unbalance as a consequence of the YAM to YAG
transformation. By taking advantage of the broad emission under 340 nm and using a blue dye, we produced white light
with CIE coordinates of (0.30, 0.36).