Self-purification construction of interstitial O in the neighbor of Eu3+ ions to act as energy transfer bridge

Abstract

We develop a strategy to investigate bridge role of O-related defects in the neighbor of Eu3+ in energy transfer (ET). By solvothermal reactions and following annealing process, Eu3+ doped ZnO nanocrystal is synthesized. After low-temperature annealing, Eu3+ ions occupy substituted sites of ZnO. High temperature annealing results in self-purification process—the separation of Eu3+ ions from ZnO lattice and generation of Eu2O3 precipitate phases. However, in this case, the proportion of individual Eu2O3 particles is extremely low if they are separated. The precipitate phases have paralleled edges and parallel to (011¯1¯) plane of ZnO. By self-purification separation, these O-terminated planes are easy to couple with Eu3+ ions, and form Eu3+ trap state. In order to maintain hexa-coordinate of Eu3+ ions, many O-related vacancies and interstitial defects are generated in the interface of ZnO/Eu2O3, among which interstitial O (Oi) in the neighbor of Eu3+ ions plays an important role in balance charge and ET. Thus, it is not strange to observe enhanced luminescence peak in self-purified samples.

Co3O4 Nanoparticles with Ultrasmall Size and Abundant Oxygen Vacancies for Boosting Oxygen Involved Reactions

“…However, it is hard to introduce oxygen vacancies in free ultrafine nanoparticles, because the metal‐oxygen bonds are strengthened by the surface tension as the particle size is reduced to the nanoscale . Meanwhile, self‐purification effect becomes striking at nanoscale, making oxygen vacancies unstable in nanoparticles . Therefore, there exists a contradiction between creating oxygen vacancy and reducing particle size.…”

Many-body electronic structure calculations of Eu-doped ZnO

“…Besides Eu, optical emission from rareearth orbitals has been achieved in ZnO nanowires implanted with erbium and ytterbium [5] and thin ZnO films doped with erbium, samarium and europium [11][12][13][14]. The above experimental investigations have suggested explanations for the optical activation of rareearths in ZnO [15,16] by means of substitutional hydrogen incorporation [15] or formation of defect complexes [8,16,17].…”

Density Functional Theory Studies of Zn12O12 Clusters Doped with Mg/Eu and Defect Complexes

“…From the above trends in formation energy, it can be concluded that Eu doped to the Zn site is a favorable dopant in ZnO cluster and Eu can also assist the formation of native point defects. The ease of formation of defect complexes involving Eu and Mg than single point defects has also been observed in ZnO nanosheets previously [21,22]. For further analysis of magnetic, electronic and optical properties, we have only taken the lowest energy doping configurations into consideration.…”

“…Specifically, Eu ? Mg is a favorable dopant combination, as the presence of a greater number of defect species created by the Mg incorporation helps in stabilizing Eu ions in the ZnO nanosheet [21,22]. In addition, Mg dopants is perfect to tune the band structure for deep UV applications as it widens the ZnO band gap.…”