Optical Absorption Intensity Research Articles

3D/2D lead-free halide perovskite CsSnBr3/MoX (X = Se2, SSe, S2) heterostructures for high-efficiency solar cell: Interface engineering strategies and transition of band alignments

The rapid progress in the fabrication of van der Waals (vdW) heterostructures based on perovskite has significantly advanced the fields of optoelectronics and solar cells by integrating the exceptional properties of different materials. Overall, perovskite-based vdW heterostructures display unique functional characteristics due to their varied type-I, type-II, and type-III energy band configurations. However, it is a challenge to achieve flexible regulation of band edge alignment in heterostructures for different applications. Using first-principles density functional theory, we systematically study the electronic and optical properties of vdW heterostructures system consisting of three-dimensional lead-free all-inorganic halide perovskite materials CsSnBr3 and MoX (X = Se2, SSe, S2). The research results show that in the CsSnBr3/MoX vdW heterostructures, type I, II, and III transitions of band arrangements are achieved through interface engineering strategy to adapt to different applications. Meanwhile, by calculating the light absorption efficiency of the constructed 3D/2D vdW heterostructures, it was found that the interface effect enhances the optical absorption range and intensity of the perovskite-based heterostructures. The theoretically estimated power conversion efficiency (PCE) of the heterostructure thin-film solar cell reaches 21.4 %. The results of our research indicate that the controllable band alignment of CsSnBr3/MoX heterostructures has significant potential for future applications in optoelectronics.

Exploring the potential of bismuth-containing silicate borate glasses for optoelectronic devices and radiation protection

This study studied novel bismuth silicate borate glasses with different bismuth oxide (Bi2O3) concentrations for their optical and γ-radiation shielding capabilities. The glass samples were characterized using UV–Vis–NIR spectroscopy to determine their optical properties, including the optical absorption spectra, absorption edge, and optical band gaps. The FLUKA algorithm was used to determine the radiation shielding parameters in the energy range of 0.01–15 MeV. The results revealed that the optical absorption edge and intensity were influenced by the Bi2O3 concentration, with the highest absorption observed in the sample with 35 mol% Bi2O3. The direct and indirect optical band gaps decreased with adding Bi2O3 up to 15 mol%, then increased at 25 mol%, and then reduced to the lowest value at 35 mol%. The system's crystallite size grew as the amount of Bi2O3 in the sample increased, as revealed by XRD. With increasing Bi2O3 content, it was discovered that the mass attenuation coefficient (μm) and radiation shielding effectiveness rose. The effective atomic number (Zeff) values increased as Bi2O3 content grew. T0.5 values of the glass samples increased as the energy increased and decreased as the Bi2O3 concentration increased. These findings suggest that prepared glasses with high Bi2O3 concentrations have potential applications in radiation shielding and optoelectronics.

1.06 μm NIR emission of Nd3+−embedded in mixed alkali borate glasses for lasing application

The Nd3+-embedded in mixed alkali borate glasses (LNKBNd) were synthesized by melt quenching technique. The physical, optical and near-infrared luminescence properties were analyzed. The density, refractive index and optical absorption intensity were found to increase with Nd3+ concentration. The 4I9/2 → 4G5/2+2G7/2 transition demonstrated the highest absorbance compared to other transitions. Near-infrared (NIR) fluorescence measurements of the revealed a strong NIR emission at 1.06 μm corresponding to 4F3/2→4I11/2 transition when excited with an 808 nm diode laser, and the maximum emission intensity was obtained from the LNKBNd glass with 0.5 mol% of Nd3+. The Judd-Ofelt theory (JO) was applied for calculating the cross-section of stimulated emissions of the LNKBNd glass with 0.5 mol% of Nd3+. The trend of JO parameters was found as Ω4 > Ω6> Ω2, indicating the rigid nature of the present glasses. The radiative properties at 1061 nm were determined as as AR = 6359 s-1, βRexp = 0.808, and σe = 9.75 × 10-20 cm2. The obtained results suggested that the 0.5 mol% of Nd3+ -embedded in LNKBNd glass has a potential for use as pivotal luminescent devices in the 1.06 μm lasing applications.

Photocatalytic performance of Fe3O4-TiO2 in the degradation of methylene blue dye: Optimizing the usability of natural iron sand

Methylene blue dye is still widely used as a clothing dye in the textile industry. Therefore, it is necessary to process this dye waste before it enters water bodies so that it does not damage the environment. The aim of this research was to optimize the function of magnetite (Fe3O4) extracted from iron sand combined with TiO2 for degrading methylene blue dye. The iron sand was extracted using a bar magnet, sieved, washed, milled, and dried. Iron sand (20 g) was converted into magnetite using the co-precipitation method with a stirring speed of 800 rpm at a temperature of 80 °C for 30 min. Magnetite was mixed with TiO2 with 30 % ethanol using a mechanical stirring method. The characteristics of Fe3O4-TiO2 photocatalyst were tested using XRD, SEM-EDX and VSM. According to the XRD data, the crystal size of the Fe3O4-TiO2 photocatalyst was below 40 nm. The presence of Fe and Ti in the photocatalyst material and their even distribution were determined by SEM-EDX testing. Through VSM, it was confirmed that soft magnetic properties were present in this material. The performance of the Fe3O4-TiO2 photocatalyst in the degradation of methylene blue dye was analyzed using a UV–Vis spectrophotometer. The test results showed that the performance of the photocatalyst improved as the contact time increased and was marked by a decrease in the optical absorption intensity; the best performance of the Fe3O4-TiO2 photocatalyst reached 93 %. Therefore, it can be concluded that iron sand as part of the photocatalyst material, play a role in the photodegradation of methylene blue dye.

Modulation of electronic and optical properties of BlueP/MoSSe heterostructures via biaxial strain and vertical electric field

Constructing van der Waals heterostructures (vdWHs) is an efficient approach for enhancing the desirable properties of two-dimensional (2D) materials and greatly expanding the range of applications of the original monolayer materials. The structure, stability, electronic and optical properties of BlueP/MoSSe heterostructures are explored by density functional theory (DFT) calculations. The different configurations of BlueP/MoSSe vdWHs are all indirect bandgap semiconductors and have similar energy band structures, with the bandgap of about 1.0 eV under the PBE method. The bandgap of the A3 (B3) configuration calculated with HSE06 method is 1.608 (1.377) eV. The A3 configuration exhibits type-II band alignment while the B3 configuration shows type-I band alignment, both of which have high stability. The bandgap and band edge of A3 (B3) configuration can be modulated effectively by biaxial strain and vertical electric field (Efield). The BlueP/MoSSe vdWHs have broader absorption range and higher absorption intensity than their monolayers. The optical absorption intensity of heterostructures is gradually improved with increasing compressive strain, and the optical absorption spectrum is red-shifted under tensile strain. We hope that our findings will provide meaningful theoretical guidance for the preparation and potential application of BlueP/MoSSe vdWHs.

A novel two-dimensional GaN/InGaN heterostructure for photocatalytic water splitting: A first-principles calculation

The pursuit of optimal bandgap and band edge positions is crucial for effective photocatalytic catalysts, leading to significant attentions in both experimental and theoretical research on modulating the band structure of semiconductor photocatalysts. In this study, the electronic, optical and photocatalytic properties of 2D monolayer GaN and GaN/InGaN heterostructures are investigated using DFT calculations. It reveals that introducing strain is an effective approach to not only alter the band gap type from indirect to direct but also influence the magnitude of the band gap. At a 10% tensile strain, a Z-type heterostructure is formed for the 2D GaN/InGaN heterostructures, which proves favorable for enhancing the efficiency of photocatalytic water splitting. However, it is worth noting that the band gap type remains indirect, necessitating additional energy for electron transitions. On the other hand, when increasing the compressive strain from − 2.5% to − 5%, the 2D GaN/InGaN heterostructure transforms from type I to type II, exhibiting direct band gaps with an enhanced light absorption range. This results in a significant redshift and increased optical absorption intensity within the visible light range, leading to a substantial enhancement in photocatalytic efficiency. Consequently, our findings demonstrate that the 2D GaN/InGaN heterostructure holds promising potential as a candidate material for efficient photocatalytic water splitting applications.

Band gap engineering of Au doping and Au – N codoping into anatase TiO2 for enhancing the visible light photocatalytic performance

We investigate anatase TiO2 doping with Au to determine the change in the band gap energy and optoelectronic properties using experimental and theoretical analysis. The structural analysis using XRD patterns revealed that the synthesized materials primarily exhibited an anatase phase of TiO2, with no impurity peaks observed. However, as the concentration of Au increased, additional diffraction peaks corresponding to Au crystalline phases were detected, indicating successful doping. Furthermore, the crystallite size was found to decrease with increasing Au concentration. We observe that the band gap reduces through substitution of Au into the TiO2 lattice from 3.09 eV to 2.78 eV, demonstrating the feasibility of bandgap tuning of the TiO2 system. A redshift for Au doped TiO2 is observed from absorption spectroscopy and optical absorption intensity using hybrid density functional theory, facilitating visible light absorption, although with potential electron-hole recombination limitations. To enhance a visible light photocatalytic activity for water splitting, we extend our work to explore the impact of N and Au codoping into TiO2 lattice. It reveals that the combination between N and Au leads to a suitable reduction in the band gap width of pure TiO2. Interestingly, Au–N codoping may decrease the effect of photogenerated carriers, produce a new optical absorption feature in the visible region, and enhance the photocatalytic performance of TiO2. This codoping configuration is also a promising photocatalyst for the decomposition of water using visible light without inducing unoccupied states.

Broadband 1.53 μm Emission and McCumber Analysis of Er3+ Doped Alkali Oxyfluorophosphate Glass for Fiber Optic Communication Material

Er3+ doped alkali oxyfluorophosphate glasses were prepared by the melted quenching method and characterized their optical and photoluminescence properties. Firstly, the chemical compositions of glasses were varied by changing alkali fluoride (LiF and NaF), whereas the concentration of Er3+ was fixed at 1.00 mol%. The optical absorption pattern and intensity were resemblance. Broadband 1.53 μm emission was one prominent peak of Er3+ in glass and the highest emission intensity was obtained for NaF glass under the stimulating at 521 nm. Secondly, the NaF glass was prepared by variation of Er3+ concentration (0.1, 0.5, 1.0, 2.0, and 4.0 mol%). The emission intensity of glasses increases with an increase in Er2O3 concentration up to 2.00 mol% and decreases for higher Er2O3 concentration, because of the concentration quenching effect. Broadband emission was observed that it covers three telecommunication windows: S, C, and L bands. The absorption and emission cross-section of 2.00 mol% of Er3+ doped alkali oxyfluorophosphate were found to be 1.3895 x 10−20 cm2 and 1.7248 x 1020 cm−2 , respectively by using the McCumber theory. Both values led to the estimate of the internal gain coefficient for 4I13/2→4I15/2 emission transition. The gain coefficient is positive when P is higher than 40%. All results point out that Er3+ doped alkali oxyfluorophosphate glass could be useful for fiber optic communication material.

Color Controllable Inorganic Pigments with Ce3+ as a Color Source.

The Ba2RE1-xCexTaO6 (RE = La, Gd, Y; 0 ≤ x ≤ 1) pigments were synthesized by a conventional solid-state reaction method to develop environmentally friendly reddish inorganic pigments. The host was the double-perovskite-type Ba2RETaO6 (RE: rare-earth elements), and the color source was Ce3+. All Ba2RE1-xCexTaO6 samples were obtained in a single-phase form as solid solutions. Rietveld refinement analysis of the Ba2RETaO6 (RE = La, Ce, Gd, and Y) samples revealed that the average bond length between RE3+ and O depends on the ionic radius of RE3+, and the shorter the RE-O length, the stronger the crystal field surrounding Ce3+. A photon energy at the maximum 4f-5d absorption of Ce3+ depended on the weighted average ionic radius (rRE) at the RE3+ site (i.e., the crystal field energy around the Ce3+ ions). In response to this phenomenon, the sample color was changed in order to orange, red, pink, and violet with a decrease in the rRE value, and a hue angle (h°) was roughly linearly related to that. For validation of the tendency, we demonstrated the synthesis and characterization of Ba2La0.5-yYyCe0.5TaO6 to obtain a more reddish color. As we exactly expected, a more reddish color was obtained while maintaining a high C value. Furthermore, the h° values for y = 0.1 and 0.2 were in good agreement with our estimation. In light of the above results, by controlling the intensity of the crystal field surrounding Ce3+ and/or the concentration of Ce3+, the optical absorption wavelength and absorption intensity of the Ba2RE1-xCexTaO6 system can be changed to adjust the color.

Influence of external electric field on electronic structure and optical properties of β-Ga2O3: a DFT study.

The influence of different electric fields on the electronic structure and optical properties of β-Ga2O3 was studied by GGA+U method. The results show that appropriate electric field intensity can regulate the band gap of β-Ga2O3 more effectively to improve the photoelectric characteristics. The band gap value of intrinsic β-Ga2O3 is 4.865 eV, and decreases from 4.732 to 2.757 eV with the increase of electric field intensity from 0.05 to 0.20 eV Å-1. The length of the O-Ga bond along the electric field increases the fastest with the electric field intensity, and the distance between O and Ga reaches 2.52 Å when the electric field intensity is 0.20 eV Å-1. A new peak appears in the real and imaginary parts of the dielectric function for β-Ga2O3 in the low frequency region under the electric field, and the conductivity increases obviously. The optical absorption peaks induced by the electric field were observed in the wavelength range of 400-600 nm. The optical absorption of β-Ga2O3 is enhanced with an increase of electric field intensity, exhibiting a maximum value with the electric field of 0.15 eV Å-1. The electric field above 0.15 eV Å-1 causes a decrease of optical absorption intensity.

Nanosheet assembled spheres Ni-MoS2 and Bi2WO6 constitute heterogeneous structures for effective degradation of ultra-high concentration organic pollutants and first-principles analysis

In this study, the Ni-doped MoS2 photocatalyst was first prepared by hydrothermal method, and then combined with Bi2WO6 to form Bi2WO6/Ni-MoS2 heterogeneous composite material. Bi2WO6/Ni-MoS2 composites have higher optical absorption intensity and photogenic carrier mobility. The 4% Bi2WO6/Ni-MoS2 composite had the best photocatalytic degradation efficiency in the photocatalytic degradation experiment of rhodamine B at high concentration. The first - principles analysis shows that the heterogeneous structure can promote charge transfer. The experimental results showed that ·OH, O2−· and h+ all acted in the reaction, and h+ played the main role. On the basis of systematic study, the mechanism of Ni-doped MoS2 and the construction of heterojunction structure to enhance the photocatalytic activity is elucidated, which provides a new reference for the design of novel efficient photocatalysts.

Dependence of light absorption on temperature changes in tattoo pigments

Purpose: to study the quantitative intensity of optical density and light absorption of the electromagnetic radiation with tattoo pigment aqueous solution depending on its temperature.Material and methods. One hundred twenty-three of the most common commercial tattoo pigments were selected for the trial; 369 samples of aqueous solutions were made of them. Optical density of each pigment sample was determined at 14 and 77 °C. Then, each sample was exposed to optical radiation (IPL xenon lamp with pulsed light) at 14 and 77 °C.Results and discussion. Electromagnetic radiation with wavelengths 532 and 1064 nm increased tattoo pigment destruction from 78,27 to 84,37 % under temperature rise from 14 to 77 °C.Conclusion. Electromagnetic radiation of the optical range with wavelengths 532 and 1064 nm cannot destroy all tattoo pigments; however, optical density of solutions changes under temperature rise which promotes destruction of coloring agents.

Influence of a Non-Resonant Intense Laser and Structural Defect on the Electronic and Optical Properties of a GaAs Quantum Ring under Inversely Quadratic Potential

We investigated the impact of a non-resonant intense laser, structural defects, and magnetic fields on the electronic and optical properties of a simple GaAs quantum ring under the inverse quadratic Hellmann potential, using the effective mass and parabolic band approximations. We obtained the energies and wavefunctions by solving the 2D Schrodinger’s equation using the finite-element numerical technique to analyze this. We considered circular polarization to calculate the dipole matrix elements, which were influenced by the laser field and structural defects in the system. This enabled us to study the linear absorption coefficients. Our results demonstrated that the presence of a laser field and a structural defect disrupt the axial symmetry of the problem. When only the non-resonant laser was present, a pattern of excited states appeared in pairs, which oscillated with the magnetic field. However, the amplitude of the oscillation decreased as the magnetic field strength increased, and these oscillations disappeared when the structural defect was introduced. It was also noted that the intensity and position of the linear optical absorption peaks exhibited a non-monotonic behavior with the magnetic field in the absence of a structural defect. However, this behavior changed when the structural defect was present, depending on the type of polarization (right or left circular). Finally, a clear improvement in the absorption peaks with an increase in the laser parameter is reported.

Surface plasmon resonance (SPR) in nanofibers of cesium titanium bromide CsTiBr3 synthesized by two-stage deposition technique

The optical phenomenon of surface plasmon resonance (SPR) finds applications in bio-imaging, photocatalysis, biosensors, LED, and solar cells. In the present study, the SPR property of lead-free nanofibers of cesium titanium bromide (CsTiBr3) synthesized by a two-stage deposition technique is reported for the first time. The optical properties and SPR in CsTiBr3 are mainly promoted by the spherical-shaped metal cluster and concave-shaped metal neck formation of cesium bromide crystal. The spherical-shaped metal cluster formation is confirmed by SEM and HRTEM analysis. The intensity of optical absorption and emission of CsTiBr3 are amplified by SPR. The intensified absorption and emission of photons make CsTiBr3 a promising candidate for solar cells, bioimaging, biosensors, and photocatalysis.

Interfacial interaction of monolayer MX2 (M=Mo, W; X=S, Se, Te)/SiO2 interfaces for composite optical fibers

The integration of two dimensional (2D) materials and optical fibers have stimulated advances in functional optoelectronic devices. In this paper, the interface between monolayer transition metal dichalcogenides (TMDs) and SiO2 is studied by first-principles method. For MX2/SiO2(M= Mo, W; X= S, Se, Te) interfaces, we found that Si-terminal is easy to form van der Waals interaction with large interlayer spacing as candidate materials. The band gap of interface containing the same SiO2 terminals decreases as the atomic radius of metal atoms increases. The potential difference of MoS2/SiO2(M3) is the highest than other selected configurations. The MX2 materials make the optical absorption of SiO2 redshift, and the structure containing Mo atom improve the optical absorption intensity of SiO2 more effectively. The composite of new materials greatly enhances the optical absorption, which provides a theoretical basis for the design of new optoelectronic devices.

The effect of Ag content on the electronic structure and optical property of α-Fe2O3

The electronic structure and optical properties of Ag-doped α-Fe2O3 with different Ag contents (1.67 mol%, 3.33 mol%, 5.00 mol% and 6.67 mol%) were studied by density-functional theory (DFT). α-Fe2O3 has the characteristics of semimetal after Ag doping, and the semimetal property increases with increasing Ag contents. Doped Ag loses less electrons for Ag-doped α-Fe2O3 than corresponding Fe (replaced iron) for pure α-Fe2O3, which led the weaker Ag-O bond than Fe-O bond before Ag doping. However, the number of losing electrons for Ag increases gradually with the increase of Ag content. For optical properties, it is found that the peaks of imaginary parts of dielectric function and extinction coefficient for Ag-doped α-Fe2O3 shift to low energy (red shift) relative to those of pure α-Fe2O3. In the ultraviolet range (200 nm-380 nm), Ag doping reduces the optical absorption intensity. However, the optical absorption is enhanced steeply with the increase of Ag contents in the wavelength of 420 nm to 1400 nm. The optical absorption intensity of 3Ag-doped and 4Ag-doped α-Fe2O3 is similar in the visible range, suggesting that excessive Ag concentration (over 3 Ag) has little effect on the optical absorption property.

ХЕЛАТУВАННЯ ДВОВАЛЕНТНИХ КАТІОНІВ ТА АНТИРАКОВА АКТИВНІСТЬПОХІДНИХ 8-ГІДРОКСИСТИРИЛХІНОЛІНІВ IN VITRO

Background. The search for new methods of cancer treatment and diagnosis are important. The disadvantages of chemotherapy drugs are the rapid acquisition of resistance and high toxicity. 8-hydroxyquinoline derivatives have a wide spectrum of biological activity and have the necessary properties for fluorescent cancer diagnosis. The aim of the study was to determine the chelation of calcium, magnesium and zinc cations by hydrophobic derivatives of 8-hydroxystyrylquinolines (8HQ) 2-(4-chlorostyryl)quinolin-8-ol (STQ-Cl) and 2-(4-nitrostyryl)quinolin-8-ol (STQ-NO2) in physiological solution, the stability of the complexes and the cytotoxicity of the compounds to prostate and breast cancer cell lines in vitro. Methods. 8HQ derivatives STQ-Cl and STQ-NO2 were used. Solutions of Ca2+, Mg2+, Zn2+ cations were prepared by the method of two-fold dilutions in 0.5-0.0078125 mM concentration range based on 0.9 % NaCl. Both individual solutions of each cation and a mixture in an equivalent molar ratio were used. The concentration of 8HQ derivatives were 0.05 mM. Optical absorption was registered in 200-700 nm wavelength range. Cytotoxicity was investigated on breast (MDA-MB-231) and prostate (DU-145) cancer cell lines. STQ-Cl and STQ-NO2 derivatives in DMSO were added to the incubation solution by four-fold dilutions (0.125–0.00003 mM). For luminescence studies, MDA-MB-231 and DU-145 cells were grown on coverslips. The final concentration of 8HQ derivatives were 5 mM. Cells were kept for 5, 10, 20 and 30 min. Luminescence was recorded under the same conditions for all samples, with an exposure time of 10 ms. Results. Mg2+ and Ca2+ (0.03125 mM) were contributed to reduce the intensity of optical absorption maxima of STQ-Cl by 1.6 and 1.3 times, respectively. The effect was most pronounced at 0.015625 mM Zn2+. Weak differences in the optical absorption of solutions were detected when STQ-NO2 was incubated with different concentrations of Mg2+ and Ca2+. The optical absorption intensity of the STQ-NO2 aqueous solution was increased at 0.015625 and 0.03125 mM Zn2+. The maximum cytotoxicity against MDA-MB-231 cells for STQ-Cl was about 80 %, and STQ-NO2 was 60 % at 0.04 mM Zn2+. DU-145 cells were more sensitive to STQ-NO2 (EC50 = 0.011 mM), but weakly sensitive to STQ-Cl (50 % at 0.125 mM). The maximum luminescence intensity was after 20 min of incubation with STQ-Cl and STQ-NO2 (5 mM) for both cells lines and was not change over time. Conclusions. The decrease of optical absorption maxima of STQ-Cl aqueous solutions in the presence of magnesium, calcium, and zinc cations was a consequence of aggregation processes. This phenomenon was probably the reason for the different cytotoxicity of STQ-Cl and STQ-NO2, as well as the presence of other mechanisms of action to cancer cells. Results was a consequence of different affinity of 8-hydroxyquinoline derivatives to magnesium, calcium and zinc cations, solubility in water, stability, aggregation of metal complexes and free compounds.

A novel black-P/blue-P heterostructure for the photovoltaic applications

First-principles calculations were performed upon a novel two-dimensional (2D) heterostructure composed of black phosphorene (black-P) and blue phosphorene (blue-P) monolayers. The results indicate that the black-P/blue-P heterostructure has high stability. The optimized heterostructure exhibits a direct band gap of 1.43 eV with the band alignment having the type-II characteristic. The carrier mobility in the black-P/blue-P heterostructure is up to 104 cm2·V−1·s−1 and anisotropic. The optical absorption intensity of the heterostructure reaches an order of 106 cm−1. The power conversion efficiency is as high as 20.25 %, implying the black-P/blue-P heterostructure as a promising candidate for the photovoltaics applications.

Enhancing orange-reddish emission of the Sm3+-doped ZnO-B2O3-SLS glasses for the potential glass phosphor material

In this paper, a series of [Sm2O3]x[(ZnO)0.5 (B2O3)0.1 (SLS)0.4]1-x, where × = 0, 0.01, 0.02, and 0.03 in weight fraction was fabricated via melt-quenching method. The influence of the samarium ion (Sm3+) concentration on the structural and optical properties was investigated. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) confirmed the samples’ glassy (amorphous) behavior. The optical absorption intensity enhanced as the dopant increased, whereas the optical band gap reduced with the progression of Sm3+ concentration. The sample’s refractive index and Urbach energy range from 2.145 to 2.203 and 0.682 eV to 0.713 eV, respectively. From the photoluminescence studies, 3 wt% Sm3+-doped samples indicate the most intense emission in the orange-reddish region among the other samples. The calculated CIE coordinates for Sm3+ doped ZnO–B2O3–SLS glasses are approximate (0.57, 0.43), near the Amber LED NSPAR 70BS produced by Nichia Corporation. In addition, the CCT of the Sm3+-doped samples at about ∼ 1750 K reveals prepared glass samples have bright orange-reddish emission. These findings indicate that Sm3+-doped in ZnO-B2O3-SLS has enhanced its orange-reddish emission and potential as an orange-reddish glass phosphor material in optoelectronic devices such as glass phosphor for LEDs.

Theoretical studies of valleytronic and optical properties in monolayer MoP2X2Y2 (XY=BTe,AlS,andGaS)

Motivated by recent extensive studies on the $M{A}_{2}{Z}_{4}$ family materials, we have predicted three ${\mathrm{MoP}}_{2}{X}_{2}{Y}_{2}$-type monolayers, including ${\mathrm{MoP}}_{2}{\mathrm{B}}_{2}{\mathrm{Te}}_{2}, {\mathrm{MoP}}_{2}{\mathrm{Al}}_{2}{\mathrm{S}}_{2}$, and ${\mathrm{MoP}}_{2}{\mathrm{Ga}}_{2}{\mathrm{S}}_{2}$, which possess excellent dynamic and thermal stabilities and peculiar electronic properties. According to first-principle calculations, the band structures show that the three monolayers are direct band-gap semiconductors with a direct band gap of $\ensuremath{\sim}1\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$. The band energy extrema occurs at $K/{K}^{\ensuremath{'}}$ points, giving rise to a pair of degenerate valleys. A large valley spin splitting is found at the valence band under the spin-orbit coupling effect, resulting in valley-contrasting Berry curvature. Moreover, these materials have strong optical absorption intensity in the visible light regions, especially ${\mathrm{MoP}}_{2}{\mathrm{Ga}}_{2}{\mathrm{S}}_{2}$. Our research shows that these three ${\mathrm{MoP}}_{2}{X}_{2}{Y}_{2}$ monolayers, as close relatives of $M{A}_{2}{Z}_{4}$ family materials, have potential valleytronics and photovoltaics applications.