A dozen predicted SiGe alloys with low enthalpies and strong absorption of sunlight for photovoltaic applications.

Silicon germanium alloy materials have promising potential applications in the optoelectronic and photovoltaic industries due to their good electronic properties. However, due to the inherent brittleness of semiconductor materials, they are prone to rupturing under harsh working environments, such as high stress or high temperature. Here, we conducted a systematic search for silicon germanium alloy structures using a random sampling strategy, in combination with group theory and graph theory (RG), and 12 stable SiGe structures in 2-8 stacking orders were predicted.

High-Throughput Information Storage in an Intelligent Response Phosphor.

Persistent phosphor has emerged as a promising candidate for information storage due to rapid accessibility and low-energy requirements. However, the low storage capacity has limited its practical application. Herein, we skillfully designed and developed NaGdGeO:Pb,Tb stimulated phosphor by trace doped Sm.

Strong Red Luminescence in Europium Complexes Solution for Anti-Counterfeiting Applications.

Eu-activated phosphors with distinct photoluminescence properties are well-suited for diverse applications, including lighting, sensing, and imaging. Despite their potential, the large-scale and energy-efficient production of Eu-doped phosphors remains a significant challenge for industrial applications. This research delves into the luminescent performance of Eu ions in nitrate solutions at room temperature by employing detailed spectroscopic characterization.

Deep-trap persistent materials for future rewriteable optical information storage.

Deep-trap persistent luminescent (PersL) materials with enriched traps, which allow signals to quickly write-in and read-out with low-energy consumption, are one of the most promising materials for information storage. In this review, considering the demand for optical information storage, we provide comprehensive insights into the data storage mechanism of PersL materials. Particularly, we focus on various "trap-state tuning" strategies involving doping to design new deep-trap persistent phosphors with controlled carrier trapping-de-trapping for non-volatile and high-capacity information storage.

Recent advances in the anti-counterfeiting applications of long persistent phosphors.

Counterfeit products have infiltrated numerous regions worldwide, causing substantial damage to the financial interests of individuals, businesses, and countries. Moreover, counterfeit goods can pose a severe risk to human health. Therefore, it is crucial to develop effective anti-counterfeiting methods and authentication technologies.

In-Plane Strain Tuned Electronic and Optical Properties in Germanene-MoSSe Heterostructures.

DFT calculations are performed to investigate the electronic and optical absorption properties of two-dimensional heterostructures constructed by Janus MoSSe and germanene. It is found that a tiny gap can be opened up at the Dirac point in both Ge/SMoSe and Ge/SeMoS heterostructures, with intrinsic high-speed carrier mobility of the germanene layer being well preserved. An n-type Schottky contact is formed in Ge/SMoSe, while a p-type one is formed in Ge/SeMoS.

Tuning Multicolor Emission of Manganese-Activated Gallogermanate Nanophosphors by Regulating Mn Ions Occupying Sites for Multiple Anti-Counterfeiting Application.

The ability to manipulate the luminescent color, intensity and long lifetime of nanophosphors is important for anti-counterfeiting applications. Unfortunately, persistent luminescence materials with multimode luminescent features have rarely been reported, even though they are expected to be highly desirable in sophisticated anti-counterfeiting. Here, the luminescence properties of ZnGaGeO:Mn phosphors were tuned by using different preparation approaches, including a hydrothermal method and solid-state reaction approach combining with non-equivalent ion doping strategy.

Tuning multicolour emission of ZnGeO:Mn phosphors by Li doping for information encryption and anti-counterfeiting applications.

Traditional fluorescent materials used in the anti-counterfeiting field usually exhibit monochromatic luminescence at a single-wavelength excitation, which is easily forged by sophisticated counterfeiters. In this work, ZnGeO:Mn,%Li ( = 0 and 20), ZnGeO-NaLiGeO:Mn,%Li ( = 50 and 70) and NaLiGeO:Mn micro-phosphors with multi-chromatic and multi-mode luminescence have been successfully synthesized a hydrothermal approach followed by an annealing treatment. As expected these Li doped ZnGeO:Mn and ZnGeO-NaLiGeO:Mn phosphors exhibit a double peak emission including a long green afterglow (∼540 nm) and red photoluminescence (∼668 nm).

Invisibility Cloak Technology of Anti-Infrared Detection Materials Prepared Using CoGaZnSe Multilayer Nanofilms.

The development of infrared stealth clothing technology and materials has been widely studied. However, the research of near-infrared stealth clothing still faces some challenges including complex preparation processes, narrow spectral ranges, and poor antidetection efficiency. To solve these questions, a CoGaZnSe multilayer film used for anti-near-infrared detection is designed and prepared by pulse laser deposition (PLD) at different pressures from 2 to 12 Pa.

Enhancing the static green up-conversion luminescence of NaY(MoO):Yb/Er microcrystals an annealing strategy for anti-counterfeiting applications.

The majority of the fabrication procedures of lanthanide-doped materials involve thermal treatment that often results in crystallite regrowth, stabilizing the specific crystal structure and resulting in luminescence enhancement. The efficiency and intensity of up-conversion luminescence are closely related to the structure and synthesis process of the materials. Herein, well-crystallized and pure tetragonal NaY(MoO4)2 microcrystals with a uniform octahedral shape have been successfully synthesized via an environmentally friendly hydrothermal method, followed by annealing treatment.

Simultaneous spectra and dynamics processes tuning of a single upconversion microtube through Yb doping concentration and excitation power.

Doping and varying pump laser parameters are the widely applied technological processes for tuning spectra to yield desirable luminescence properties and functions. For micro/nanocrystalline materials, doping is of fundamental importance in modifying electronic properties, modulating magnetism, as well as tuning the red-to-green luminescence ratio. Here we describe a tunable upconversion (UC) emission process in single NaYF:Yb/Er microtubes excitated with a focused laser.

Simultaneous quasi-one-dimensional propagation and tuning of upconversion luminescence through waveguide effect.

Luminescence-based waveguide is widely investigated as a promising alternative to conquer the difficulties of efficiently coupling light into a waveguide. But applications have been still limited due to employing blue or ultraviolet light as excitation source with the lower penetration depth leading to a weak guided light. Here, we show a quasi-one-dimensional propagation of luminescence and then resulting in a strong luminescence output from the top end of a single NaYF4:Yb(3+)/Er(3+) microtube under near infrared light excitation.

Up/down conversion switching by adjusting the pulse width of red laser beams in LaF₃:Tm³⁺ nanocrystals.

We demonstrate a versatile approach to fine-tuning the ratio of blue to near-infrared emission intensity from Tm3+ ions in LaF3 nanocrystals by adjusting the pulse widths and excitation wavelengths of red laser beams. The mechanism of color-tunable Tm3+ emission by pulse widths is explored, and a mechanism based on promoting the population of some luminescence levels and cutting off the population of others by suitably adjusting pulse duration is proposed. The underlying reason of excitation wavelength-modulated emission is ascribed to tuning absorption probability ratio of ground state absorption to excited state absorption by tuning the matching degree between the energies of excitation wavelength and ground (excited) state absorption of Tm3+.

Upconversion improvement by the reduction of Na⁺-vacancies in Mn²⁺ doped hexagonal NaYbF₄:Er³⁺ nanoparticles.

Hexagonal-phase NaYbF4:Er(3+) upconversion nanoparticles (UCNPs) have been synthesized via a co-precipitation method in high-boiling-point solvents, and remarkably enhanced upconversion luminescence, particularly in red emission bands (650-670 nm) in NaYbF4:Er(3+) UCNPs, has been achieved by Mn(2+) doping. The underlying reason for luminescence enhancement by Mn(2+) doping is explored by a series of controlled experiments, and a mechanism of enhancement based on the decrease of Na(+)-vacancies and organic adsorption is proposed. The Mn(2+) substitution disturbs the equilibrium of the charge and crystal lattice in the hexagonal-phase NaYbF4:Er(3+) UCNPs, which makes the Na(+)-vacancies that quenched luminescence become filled with Na(+) or Mn(2+) to offset the imbalance of the charge and electron cloud distortion.

Pr3+/Yb3+ co-doped beta-phase NaYF4 microprisms: controlled synthesis and upconversion luminescence.

Pr3+/Yb3+ co-doped hexagonal NaYF4(beta-NaYF4) microprisms were synthesized by the hydrothermal method, and ethylenediaminetetraacetic acid (EDTA) was introduced to control the size of the microcrystal samples. Bright upconverted fluorescence emission was observed when the samples were excited with an infrared (IR) laser at 976.4 nm.

Formation of bundle-shaped β-NaYF4 upconversion microtubes via Ostwald ripening.

In this work, the uniform bundle-shaped microtubes composed of six half-pipes are synthesized for the first time in hydrothermal solutions via an intentional delayed phase transition pathway induced by Mn(2+) doping. The structural and kinetic factors that govern the phase and shape evolution of NaYF4 microcrystals have been carefully studied, and the influences of Mn(2+) to RE(3+) ratio, the amount of trisodium citrate, and the pH value in conjunction with the intrinsic character of RE(3+) ions on the phase and shape evolution are systematically discussed. It is found that the proper Mn(2+) to RE(3+) ratio is mainly responsible for delayed phase transition process and induces interior density gradient of solid aggregate for creating hollow bundle-shaped microtubes.

Codopant ion-induced tunable upconversion emission in β-NaYF4:Yb3+/Tm3+ nanorods.

An innovative route to tune upconversion (UC) emission in β-NaYF(4):Yb(3+)/Tm(3+) nanorods through codoping a third rare-earth ion upon continuous wave excitation near 976 nm is reported. The dependence of UC emission on codopant concentration and environment temperature shows that tailored local environment and readjustable depopulation of excited-state ions are responsible for the tuning of UC luminescence. Codopant ions introduce a new distribution of active ions and a modified distance between Tm(3+) and Yb(3+) ions, making UC systems more sensitive to impurity ions than downconversion systems.

Spectroscopic study of Eu3+ doped LaF, nanoparticles prepared with different PH values.

Europium doped lanthanide fluoride (LaF3) nanoparticles were prepared through a hydrothermal method with different PH values of precursor complex solution. The influence of PH value on the luminescence properties is investigated. It was found that the local symmetry of doped ions reduced with the increase of PH value, leading to the increase of the inversion symmetry ratio.

The influence of synthesizing processes on the spectroscopic property of tetragonal LaOF:Eu3+ nanoparticles.

The tetragonal LaOF:Eu3+ nanoparticles have been successfully synthesized by three different methods including hydrothermal, solvothermal and chemical precipitation methods. Strong red fluorescence emissions were observed by exciting the samples with 532 nm laser. Under the proper conditions, the sample synthesized via chemical precipitation method presented the strongest fluorescence emission.

Luminescence enhancement and quenching by codopant ions in lanthanide doped fluoride nanocrystals.

Luminescence enhancement (LE) and quenching for lanthanide (Ln) doped nanocrystals is obtained by a second Ln(3+) ion doping method. Singly or doubly doped LaOF, LaF(3) and NaYF(4) nanocrystals are studied in detail under selective or two-color excitations. The underlying reason for LE by codoping is explored, and a mechanism of the enhancement based on the low local point symmetry effect of the matrix is proposed.

Strong photoluminescence through up and down conversion in Tm(3+)/Ho(3+):LaOF nanoparticles.

Efficient up and down frequency conversions in Tm(3+) and Ho(3+) doped LaOF tetragonal nanocrystals have been investigated. Bright fluorescence emissions are obtained in co-doped Tm(3+)/Ho(3+):LaOF tetragonal nanocrystals through UV and infrared excitation. Green florescence from doped Ho(3+) ions, which can be clearly seen with bared eyes, is obtained when Tm(3+) ion is excited.

[Spectroscopic study on the interaction of glass matrixes and nanoparticles in Tm3+ doped oxyfluoride glass ceramics].

Fluorescence emission spectra from Tm3+ in crystal phase and glass phase were separated under selective excitation of 1D2 level in Tm3+ doped transparent oxyfluoride glass ceramics containing LaF3 nanocrystals. Emissions from the crystal phase and from the glass phase were detected. The influence of the interaction between glass matrix and nanocrystals on the optical characteristics of Tm3+ ions in the two different local environments was investigated.

Optical dephasing of triply ionized rare earths in transparent glass ceramics containing LaF3 nanocrystals.

Optical dephasing of Pr3+ and Tm3+ ions doped in transparent oxyfluoride glass ceramics was studied with the two-pulse photon echo technique. It was found that the dephasing time of rare earth ions is dramatically less in nanocrystals embedded in a glass matrix than in bulk crystals. A quasi-linear temperature dependence obtained at low temperatures proved that the long-range interaction of the ions inside the nanocrystals with the two level systems of the glass matrix dominates the optical dephasing.