Polarization-Modified Upconversion Luminescence in Er-Doped Single-Crystal Perovskite PbTiO₃ Nanofibers

Abstract

Understanding the energy transition which is influenced by doping ions and host materials in the upconversion (UC) physical processes is of vital importance for further optimizing performance and extending applications of UC materials. In this work, we have selected 4% Er-doped perovskite PbTiO 3 (PTO) nanofibers as a model system to explore the effects of tetragonality and polarization on UC photoluminescence (PL) properties. By means of in situ X-ray diffraction, the tetragonality and polarization of these nanofibers have been determined to gradually decrease with an increasing of the temperature from 50 to 300 K, leading to obvious enhancements in UC green band emission of 523 nm (about 43 times) and red band emission of 656 nm (about 8 times), in contrast to the decreased green and red UC intensities in Er-doped BaTiO 3 or PTO particles. Moreover, the significant enhancement in the intensity ratio of green to red bands from 0.17 to 0.86 has been achieved, indicating that the emission enhancement is highly wavelength-dependent. On the basis of in situ UC decay curves from 50 to 300 K, the UC lifetimes of the 4 S 3/2 and 4 F 9/2 level have been derived to be 128.04 ± 0.47 μs and 278.10 ± 1.07 μs at 50 K, respectively, and the values are basically maintained as the temperature increases. The observed UC phenomena in Er-doped perovskite PTO nanofibers can be ascribed to an assisted effect of the low-energy E(1TO) phonon on the UC process. Such phonon energy can be easily tailored by the tetragonality and polarization; thus, a modification of UC emissions in Er-doped PTO nanofibers has been achieved. The findings in this work could provide new insights into understanding the UC process in perovskite oxides and offer an opportunity to tune UC emission by an external field, such as an electric field, in addition to temperature.

Structurally tuned lead magnesium titanate perovskite as a photoelectrode material for enhanced photoelectrochemical water splitting

“…The substitution of Pb and/or Ti ions by Mg, presenting smaller ionic radius, induces shrinkage of the lattice by the direct consequence a decrease in the cation/anion (c/a) ratio. In addition to the structural change, the change of the c/a ratio induces a change in the incorporation process on the two main sites and a variation of the total amount and nature of structural vacancies created for the charge compensation induced by the substitution of the main ions by the dopants [68]. The changes in the lattice constants indicated that magnesium atoms have been systematically dissolved into the crystal structure.…”

Hydrothermal Synthesis and Up‐conversion Luminescence of Ho3+/Yb3+ Co‐doped PbTiO3

“…In the last decades, various photoluminescence have been obtained in perovskite‐type materials, offering the potential applications ranging from flat‐plane displays to lighting . Among them, most of the previous literatures focus on adjusting the UC PL properties by introducing Er ions into perovskite oxides , . Although there are some pioneers' works related to the Ho ions doped perovskite‐related oxides, the impacts of the doping Ho 3+ ions content on PbTiO 3 nanomaterials are rarely reported.…”

Recent Progress in Lanthanide-Doped Inorganic Perovskite Nanocrystals and Nanoheterostructures: A Future Vision of Bioimaging

“…Understanding the impact of dopant ions in host materials on energy transitions via the UC process is crucial for further extending the properties and applications of UC materials. In this regard, Gong et al [61] reported the Er-doped PbTiO 3 (PTO) perovskite nanofibers as model systems for exploring the effects of tetragonality and polarization on their UCL properties. A clear emission enhancement was observed in the UC green band at 523 nm and in the red band at 656 nm of Er-doped PTO perovskite nanofibers when compared with those in Er-doped BaTiO 3 or PTO particles.…”