Making Eu²⁺- and Sm²⁺-Doped Borates Fit for Solar Energy Applications

Abstract

Despite the development of many luminescent materials for various applications, only a few of these phosphors are applicable for solar energy generation applications. This study used the conventional solid-state reaction method to synthesize different strontium borate compounds codoped with divalent europium and samarium ions. The material was optimized by varying the experimental procedure, the molar ratio of the boron, and the molar ratios of both codopants. Strontium hexaborate doped with a relatively high europium concentration and a low samarium concentration (Sr 0.89 B 6 O 10 :Eu 0.1 , Sm 0.01 ) gave the optimum optical properties. These properties included a broad excitation range from 220 to 600 nm containing contributions from divalent europium and samarium ions. The material exhibited strong and narrow emission in the region from 650 to 850 nm following radiative transitions within the divalent samarium ions. The internal luminescence quantum efficiency of the optimized material was 79% (λ ex = 508.5 nm). There was no spectral overlap between the excitation and emission spectra, thereby reducing the reabsorption probability. These marked characteristics make this phosphor material appropriate for use as a solar radiation converter or for use in luminescent solar concentrators.

Enhanced Durable Corrosion Resistance of Samarium-Doped ZnO Solid Solution Materials by 4f Electrons of Samarium Atoms

“…Although the Sm element has some application value in the field of metal corrosion protection, its advantages are not obvious compared to other metal corrosion inhibitors. Doping is the process of introducing foreign impurities into semiconductor materials to change their electrical and optical properties. − For zinc oxide (ZnO) material, doping with rare earth elements such as cerium, Sm, europium, or gadolinium elements can change its electrochemical and optical characteristics. − Two forms of displaced oxygen atoms are present on the surface of ZnO material: one is surface oxygen atoms that form ZnO material, and the other is surface oxygen atoms occupied by oxygen defects. − When rare earth elements are doped into ZnO material, it can change the content and distribution of surface oxygen atoms, changing the type and number of surface oxygen atoms and thus altering the surface chemical reactions of ZnO material. , The f electrons of rare earth elements can participate in the electron transfer process of redox reactions, thereby regulating the redox properties of the ZnO material surface …”

Quantifying Mie Scattering in Luminescent Solar Concentrators for Improved Performance

“…In contrast to reabsorption and re-emission, which can be directly evaluated by the measurable PLQY and absorption coefficient, the scattering coefficient, which is a measure of the ability of scattering, cannot be directly measured. Although the approach used to estimate the Rayleigh scattering coefficient of the LSC has been reported, , the method for estimating the Mie scattering coefficient of the LSC is rarely reported, despite the fact that it has an important impact on the LSC performance, − especially when the sizes of fluorophores are close to the wavelength of the light. It is still challenging to characterize the Mie scattering due to the following reasons.…”

Physicochemical Characterization of the Hybrid Molybdate–Tungstate Materials for Solid-State Lighting

“…Suitable hosts for rare earth-based phosphors are known as borates, , alumina, molybdates, − niobates, ,, phosphates, − fluorides, ,− tungstates, − and so on. In the past few years, great attention has been focused on the molybdate–tungstate matrix ,− by virtue of its luminescence and structural properties.…”