High Optical Conductivity Research Articles

Structural, electronic, magnetic, optical and thermoelectric properties of ferromagnetic double perovskites K2ScCoX6 (X = F, Cl): A first-principles study

To identify a promising alternative to lead-based materials for solar cell application, we investigated the different physical properties of K2ScCoX6 (X = F, Cl) perovskites. Both materials have ferromagnetic ground state. The obtained optimize lattice constants are found to be 8.48 Å and 10.04 Å for K2ScCoF6 and K2ScCoCl6 respectively. Our finding indicate that these materials exhibit excellent structural, mechanical, the thermal stability, as evidenced by their Goldsmith’s tolerance factor, elastic parameters, and negative formation energies. The formation energy is found to be -2.4 and -2.1 eV/atom for K2ScCoF6 and K2ScCoCl6 respectively. The electronic properties reveals that both materials have semiconducting nature. Notably, we observed low direct bandgap of 0.93 eV for K2ScCoF6 and 1.22 eV for K2ScCoCl6, which contrast with the typically large bandgap values reported for most halide double perovskite. The calculated values of Poisson’s and Pugh’s ratios, along with positive Cauchy’s pressure, suggest a ductile nature for these compounds. Additionally, the optical properties show high absorption and optical conductivity, coupled with low reflectivity and minimal energy loss in lower energy ranges. These results suggest that the halogen-based double perovskite materials have significant potential as photovoltaic absorber materials in solar cell applications. Furthermore, their higher Seebeck coefficients, power factors and low thermal conductivity at room temperature underscore their potential for thermoelectric applications.

Effect of C additives with 0.5 % in weight on structural, optical and superconducting properties of Ta–Nb–Hf–Zr–Ti high entropy alloy films

We investigated the superconducting (SC) properties of Ta–Nb–Hf–Zr–Ti high-entropy alloy (HEA) thin films with 0.5 % weight C additives. The C additives stabilize the structural properties and enhance the SC critical properties, including μ0Hc2 (13.45 T) and Tc (7.5 K). The reflectance of the C-added HEA film is enhanced in the low-energy region, resulting in a higher optical conductivity, which is consistent with the lower electrical resistivity. In addition, we observed SC vortices in the C-added HEA film using magnetic force microscopy. The magnetic penetration depths (λ) of the pure HEA and C-added HEA films were estimated from their Meissner force curves by comparing them with those of a reference Nb film. At 4.2 K, the λ of the C-added film is 360 nm, shorter than that of the pure HEA film (560 nm), indicating stronger superconductivity against an applied magnetic field.

Optical and optoelectrical characterizations of Cu2ZnSn3S8: A potential nominee for optoelectronic and photovoltaic applications

A successful trial has been accomplished in synthesizing a stable phase of Cu2ZnSn3S8 (CZTS8). The deposited thin films have been obtained by utilizing the chemical bath deposition (CBD) process. Basic characterizations have been applied to check the formation of our new stable material. The formed CZTS8 films disclose the amorphous nature as presented in the x-ray diffraction (XRD) patterns. Also, an enhancement in film morphology has been obtained by expanding the film thickness. Moreover, optoelectrical and linear/nonlinear optical features have been studied for the as-deposited films. Our material has interesting characteristics to be a promising window sheet for thin film solar cells. It reveals a tendency to be an n-type semiconductor material. Further, it shows high optical absorption as well as high optical conductivity. Moreover, it has a direct optical transition, and its energy gap is varied in the range (3.89 eV - 3.94 eV). Additionally, the dispersion and optoelectrical indices were affected by the variation in both film thickness and film roughness. Furthermore, the nonlinear optical indices χ(1),χ(3) and n2 were improved via the increase in film thickness. A satisfactory correlation has been performed between all of the evaluated parameters. The main goal of this study has been achieved by obtaining n-type material by increasing the Tin and Sulfur contents in the CZTS8 as compared with the known p-type material (Cu2ZnSnS4) CZTS4. The revealed findings acknowledge that CZTS8 could be a promising nominee for either optoelectronic or photovoltaic applications.

Band structure engineering to improve the optical and thermoelectric properties of Rb2AgXBr6 (X=Al, In, Ga) for energy applications within DFT framework

In the current study, we have employed density functional theory to evaluate thermoelectric, optical and electronic properties of rubidium bromide based double perovskites. It has been found that all three compounds i.e. Rb2AgAlBr6, Rb2AgGaBr6 and Rb2AgInBr6 have a direct band gap and the band gap appears at Γ symmetry point. The band gap of Rb2AgAlBr6 = 0.92 eV and of Rb2AgInBr6 = 0.29 eV whereas for Rb2AgGaBr6 has shown bands overlapping. The merged band gap of Ga-substituted material imparts in it excellent conductivity which makes it a potential candidate for application in conducting materials. Among all Rb2AgAlBr6 composition showed efficient TE properties with power factor of around 3.0 x 1011 W/msK2 and ZT value of 0.3. The optical properties found consist of high absorption coefficients (about 106 cm−1), low reflectivity (around 1–15 %), and high optical conductivity (approximately 1015sec−1).

Investigation of structural, electronic, optical, and mechanical properties of perovskite CsPbBr3 material through induced pressure for photovoltaic applications: A DFT Insights

Herein, perovskite CsPbBr3 material was computationally explored at pressure limits from 0.0 to 8.0 GPa using a 5-step (2GPa gap) calculation. CASTEP (Cambridge Serial Total Energy Package) program is used which is based on density functional theory (DFT), with an ultra-soft (US) pseudo-potential (SP) plane wave and the GGA-PBE exchange–correlation functional. When the pressure increases from 0.0 to 8.0 GPa, the bandgap decreases from 1.84 to 0.60 eV. In comparison to higher pressures, the bandgap decreases significantly until 8.0 GPa. The mechanical properties of the compound at various pressures are also investigated, which indicates that the compound is mechanically ductile and stable in nature. Various optical characteristics, such as the refractive index, loss function, absorption coefficient, and reflectivity, have been determined under pressure limits from 0.0 to 8.0 GPa. For solar cell applications, a compound with high absorption, refractive index, and optical conductivity is optimal.

Ab initio investigation of the structural, mechanical, electronic, thermodynamic, and optical properties of V2FeNiGe2 and Hf2FeNiSb2 double half-Heusler compounds

In the present work, using ab initio density-functional theory methods based on the Quantum ESPRESSO package, we have investigated the structural, elastic, electronic, and optical properties of 18-electron V2FeNiGe2 and Hf2FeNiSb2 double half-Heusler alloys. The calculated elastic properties suggest a ductile behavior with metallic bonding for V2FeNiGe2 and a brittle behavior with covalent bonding for Hf2FeNiSb2. The thermodynamic properties (Debye temperature, melting temperature) are also predicted and discussed for the studied alloys. The alloys are found to be semiconducting with indirect band gaps of 0.53 eV for V2FeNiGe2 and 0.47 eV for Hf2FeNiSb2. We also computed and analyzed their optical properties (dielectric function, optical conductivity, refractive index, absorption index, and reflectance) and our calculations suggest that both materials have high absorption coefficient and optical conductivity in the UV as well as visible region. The results make them potential candidates for the manufacture of opto-electronic devices.

Insights and perspectives on PVDF/MgO NCs films: Structural and optical properties for optoelectronic device applications

In the current investigation, pure polyvinylidene fluoride (PVDF) and PVDF-MgO nanocomposite (NC) thin films are fabricated via solvent casting method using PVDF as a polymer matrix with different proportions of magnesium oxide (MgO) (0.5–2 wt%). The structural, morphological and optical properties of the prepared polymer NCs are studied by using XRD, FTIR, SEM, Raman and UV–Vis spectroscopy techniques. The α and β phases are detected in XRD measurements. MgO powder peaks are in good agreement with the reported literatures. The average crystallite size, lattice strain, and dislocation density of the prepared thin films are estimted by using Williamson-Hall (W-H) plot. SEM micrographs reveals the fluorine-containing carbon chain network that forms the spherulite and fiber-like structure in the PVDF/MgO NCs films. The Raman and FTIR spectra of PVDF/MgO and pure PVDF films are also evaluated. UV–Vis spectroscopy is used to examine the absorbance, transmittance, and reflectance spectra of pure PVDF and PVDF/MgO NCs thin films. The dipole polarization interaction causes the absorption coefficient, direct band gap, indirect band gap, optical activation energy, and skin depth of pure PVDF and PVDF/MgO thin films to decrease, whereas increasing the dielectric constant at high frequency value, refractive index, loss, optical conductivity, and dielectric constant per effective mass of NCs films. Optical dispersion parameters are estimated by the single oscillator model. The obtained results can be employed in the possible applications in supercapacitors. The method used for the preparation of thin films are inexpensive and eco-friendly.

Au/Nb2O5 terahertz-gigahertz electro-optical filters designed for high frequency applications

Herein enhanced broad band filters are fabricated by deposing thin films of Nb2O5 onto glass and semitransparent Au nanosheets using the ion coating technique. Remarkable enhancement in the surface roughness of the films and in the visible and infrared light absorption by more than 270% and 750%, respectively, is achieved by coating the films onto Au nanosheets. Au nanosheets redshifted the energy band gap and initiated the free carrier absorption in the Nb2O5 films. As terahertz band filters, Au/Nb2O5 interfaces exhibited higher dielectric constant, higher optical conductivity and higher terahertz cutoff frequency values. Au/Nb2O5 optical filters showed terahertz resonator characteristics displaying six resonance modes two, three and one of which are dominant in the infrared, visible and ultraviolet ranges, respectively. On the other hand the impedance spectroscopy analyses for Au/Nb2O5/Au (ANA) filter showed microwave resonator characteristics with cutoff frequency values reaching 700 GHz for signal carriers of driving frequency of 1.65 GHz. ANA devices exhibited negative capacitance effect in a wide range of driving frequency domain. The features of the Au/Nb2O5 films demonstrate their potential for use as gigahertz-terahertz broad band electro-optical resonators suitable for high frequency applications.

First-Principles Analysis of the Effects of Halogen Variation on the Properties of Lead-Free Novel Perovskites AlGeX3 (X = F, Cl, Br, and I).

To commercialize optoelectronic products and perovskite-based solar cells, nontoxic inorganic cubic metal halide perovskites have gained popularity. This study presents the structural, mechanical, electronic, and optical properties of novel lead-free metal cubic halide perovskites AlGeX3 (X = F, Cl, Br, and I) using the first-principles Density Functional Theory (DFT) approach. The verification of the mechanical stability of all compounds is conducted through Born stability criteria and formation energy. All of the compounds in the elastic investigations exhibit anisotropy, ductility, and elastic stability. The electronic band structures estimated by HSE06 and GGA-PBE functional demonstrate indirect to direct band gap transformation after substituting the halide F with the halides Cl, Br, and I. The tunability of halide-dependent energy bandgaps and the underestimation of energy band gaps are also noticed for the studied compounds by comparing the results obtained from the GGA-PBE functional and HSE06 investigations. The origins of bandgap transformation as well as halide-dependent energy gap modulation are explained by both the partial and total density of states (PDOS and TDOS). The results presented here suggest that all the compounds show low reflectivity, a high absorption coefficient, and also high optical conductivity in the visible and UV regions, making these materials suitable for multijunctional solar cells. Also, these materials have a greater impact on other optoelectronic device applications. Compared to other compounds, the optical investigation reported here demonstrates that AlGeI3 exhibits excellent optical conductivity and absorption in the visible region.

A DFT study to explore structural, elastic, mechanical, phonon, electronic and optical properties of halide perovskites AgXF3(X=Be,Ca)$$ {\mathrm{AgXF}}_3\left(\mathrm{X}=\mathrm{Be},\mathrm{Ca}\right) $$ with PBEsol, TB‐mBJ and SCAN functionals

AbstractFirst principles calculations have been performed using full potential linearized augmented plane wave, FP‐LAPW, within Wien2k to elucidate structural, elastic, mechanical, phonon, electronic and optical properties of lead free halide perovskites . The energy volume curve fitting is used to examine structural stability. For structural optimization and mechanical properties, we employed Perdew–Burke–Ernzerhof generalized gradient approximation and PBEsol, revised for solids, exchange and correlation functional. The optimized lattice constant of and is 3.631 and 4.349Å. The elastic constant , and are computed to extract different mechanical parameters like Poisson's ratio, Pugh's ratio, bulk modulus, shear modulus, Young's modulus, anisotropic ratio, Cauchy pressure and shear constant. The mechanical parameters exhibit greater structural, mechanical and dynamical stability of than . The electronic and optical properties are calculated by using TB‐mBJ and SCAN potentials in addition to PBEsol. The electronic band gap of and is 4.71 and 6.01 eV with TB‐mBJ and both perovskites are indirect band gap materials. The optical response of these perovskites against wide range of incident electromagnetic radiation is assessed by calculating absorption, reflection, optical conductivity, dielectric constant, energy loss function and refraction. Strong absorption, high optical conductivity and low reflectivity indicates that and are promising materials for photovoltaic applications.

Enhanced optoelectronic and catalytic properties of Sm doped SnO2 thin films

Herein, we report the optoelectronic and malachite green (MG) aqueous dye model pollutant degradation characteristics of samarium (Sm) doped tin oxide (SnO2:Sm) thin films deposited on glass substrate by chemical spray pyrolysis technique. The tetragonal crystal structure and polycrystalline nature were elucidated from X-ray diffraction (XRD) analysis, and the calculated crystallite size using Scherrer's relation was found to vary between 36 and 45 nm. A high optical transparency of 92 % was achieved for SnO2:Sm (3 wt%). The extrapolation of linear fit indicates a slight decrement in the band gap. Energy dispersive X-ray analysis (EDAX) confirmed the presence of Sn, O and Sm elements and their composition. The quantitative compositional percentage of Sn, O and Sm was determined by X-ray photoelectron spectroscopy (XPS) analysis. The scanning electron micrographs (SEM) showed polyhedron-like shaped grains with cracks and void-free film surface. The 3 wt% Sm:SnO2 thin film exhibited a higher average surface roughness (19.63 nm) than other films. Strong ultraviolet (365 nm), blue (493 nm), and green (520 nm) emissions were observed for all the films, as recorded by photoluminescence (PL) studies. High electron concentration (7.9 × 1020/cm3), low resistivity (0.356 × 10−3 Ω cm), and a high figure of merit (FOM, 5.11 × 10−2 Ω−1) were obtained for 3 wt % of SnO2:Sm thin films. Furthermore, a relatively high photocurrent (8.22 mA) was attained for the 3 wt% Sm:SnO2 thin film. Enhanced photocatalytic efficiency (95 %) was achieved for the 4 wt% Sm:SnO2 film against MG dye aqueous solution. The results obtained in the present study demonstrate high optical transparency, electrical conductivity, enhanced FOM, and photocatalytic degradation efficiency for 3 and 4 wt% Sm-doping, respectively. Therefore, Sm-doped SnO2 could be useful for developing and designing novel devices for optoelectronic and photocatalytic applications.

DFT analysis of the electronic, optical, phonon, elastic, and mechanical features of ternary Rb2XS3 (X = Si, Ge, Sn) chalcogenides

Density functional theory (DFT) calculations were executed for the titled features of hitherto unreported Rb2XS3 (X = Si, Ge, Sn) chalcogen compounds. All compounds were found to be in semiconducting character where they demonstrate high-k dielectric properties, high optical conductivity, high refractivity and reasonable absorbance. In addition, obtained phonon dispersion curves of all compounds with positive phonon frequencies stipulate the dynamical stability. Also, computed elastic stiffness constants prove mechanical stability and bilateral agreement between Pugh ratio analyses with Poisson ratio results confirms the ductile mechanical feature of all addressed compounds. Overall, with satisfactory optical, elastic and mechanical aspects, Rb2XS3 (X = Si, Ge, Sn) chalcogenides can be promising materials for recent optoelectronics and microelectronics with diverse applications.

Anthocyanins of Delonix Regia Floral Petals: A Novel Approach on Fluorescence Enhancement, Forster Resonance Energy Transfer Mechanism and Photostability Studies for Optoelectronic Applications.

In this work, we focused on extracting the anthocyanin dye in acetone, butanol, ethanol, and water solvents from Delonix regia flowers by a simple maceration extraction process. The identification of functional group analysis, vibrational studies, energy transfer mechanisms, optoelectronic properties, photostability studies, FRET-assisted potential light emissions and photometric properties of the anthocyanin dyes are successively investigated. FTIR spectroscopy and vibrational studies have confirmed the existence of polyphenolic groups in 2-phenyl chromenylium (anthocyanin) dyes. The optoelectronic results show the least direct bandgap (2.04eV), indirect bandgap (1.55eV), Urbach energy (0.380eV), high refractive index (1.20), dielectric constant (2.794), and high optical conductivity (1.954 × 103 S/m) for the anthocyanin dye extracted found in water solvent. The photoluminescence properties such as Stoke's shift, high quantum yield, and lifetime results show that anthocyanin dyes are promising candidates for red-LEDs and optical materials. The absorption and emission spectra of the anthocyanin dyes follow the mirror image rule and the Franck-Condon factor exists between vibrational energy levels corresponding to all the electronic transitions. The excellent correspondence between the absorption and emission spectra reinforces that the anthocyanins are efficient (46%) FRET probes. Further, photometric properties such as CIE, CRI, CCT and colour purity results of anthocyanins in all studied solvents revealed that this material exhibits orange to red shades (x = 0.48 → 0.54 and y = 0.36 →0.45) and is well suitable for have great potential in the manufacturing of Organic-LEDs and other optoelectronic device applications.

Investigation of structural, electronic, optical and thermoelectric properties of hallide double perovskite Rb2AlAgX6 (X = Cl, I): A first-principles DFT study

In order to meet the demands of the energy consumption, double perovskites (DP) are a dependable green energy source. Consequently, there is a great deal of promise for thermoelectric and optoelectronic device applications when studying these perovskite halides. Our work examined the thermoelectric and optoelectronic properties of Rb2AlAgCl6 and Rb2AlAgI6 halides using Density Functional Theory (DFT). The tolerance factor and energy of formation for the halides that were examined show that they are stable in the cubic phase, structurally and thermodynamically. We calculated the bandgaps for Rb2AlAgCl6 (Eg = 3.82 eV) and Rb2AlAgI6 (Eg = 1.321 eV) using mBJ potentials, and compared them to the reported values. The optical characteristics of the materials under investigation were revealed through the use of a complicated dielectric function. The computed optical findings show that the materials are suitable for optoelectronic applications, with maximal light absorption occurring in the ultraviolet (UV) and infrared (IR) ranges. Optical parameters obtained includes large values of absorption coefficients (∼105cm−1), low reflectivity (∼1–15 %), and high optical conductivity (∼1015 sec−1). Thermoelectric properties revealed enhanced power factor for Rb2AlAgI6 as compared to Rb2AlAgCl6. These results imply that these materials are appropriate for application in optical and thermoelectric devices.

Investigating stress-induced effects on the multifaceted properties of cubic NaTaO3 perovskite oxide: prospects for advanced applications

This study explored the structural, optoelectronic, elastic, mechanical, and thermodynamic behaviour of NaTaO3 cubic perovskite oxide, under varying stress levels. Geometric property analysis reveals a decrease in lattice constants from 4.1 Å to 3.7 Å and cell volume from 71.1–53.4 Å3 as stress increases from 0 to 100 GPa. X-ray diffraction analysis indicated the stable cubic phase with slight peak shifts, demonstrating the material's structural flexibility. Electronic properties revealed an initial increase in the band gap (1.698 eV to 1.936 eV) with applied stress up to 60 GPa, which could be attributed to complex interactions within the material's electronic structure. Optical property analysis suggested that NaTaO3 possessed high optical absorption and conductivity, along with low reflectivity. Furthermore, elastic constants meeting the Born-stability condition (C11 – C12 > 0, C11 + 2C12 > 0, and C44 > 0) confirm the material's mechanical stability. Additional characteristics like the Poisson ratio, Cauchy pressure, and Frantsevich ratio highlighted the ductile and anisotropic nature of NaTaO3. Thermodynamic and phonon dispersion analysis suggested that NaTaO3 can withstand high-stress levels, evidenced by its elevated Debye temperature, indicating superior mechanical stability and increased resistance to thermal degradation. Based on these findings, NaTaO3 proposed as a potential candidate for photovoltaic and thermoelectric devices.

Study of structural, dynamical stability, electronic magnetic and optical properties of RbSnO3 oxide perovskite compound using the density functional theory approach

This study investigates the structural, phonon, elastic, electronic, magnetic and optical properties of cubic perovskite RbSnO3. The calculations are based on the linearized augmented plane wave method with total potential (FP-LAPW), implemented in the Wien2k code; two approximations are used for calculate properties, PBE-GGA and TB-mBJ . The values of the tolerance factor and the formation energy of this material indicate that it is stable in the cubic structure of Pm3̅m symmetry. The Born criteria for the compound under study confirm its mechanical stability, while its phonon dispersion curves confirm its dynamic stability. The results of the electronic and magnetic properties show that the compound is ferromagnetic (FM) semi-metallic (DM) with semiconductor behavior in the majority spin channel and with an indirect gap in the M → Γ direction and having a total magnetic moment equal to 1 μB and a Curie temperature equal to 527 K. Optical spectra of the compound show high optical conductivity in the infrared region and towards the end of the spectrum at around 6 eV, high reflection in the infrared region with a maximum at 0.25 eV, and high absorption in the ultraviolet region at 6 eV. In view of these results, the RbSnO3 perovskite can be a promising candidate for spintronics applications as it can be used in optical devices working in the ultraviolet (UV) light region.

First principles study of structural, electronic, optical and thermoelectric properties of Ag3XY2 (X = Cu, Cd, Zn: Y[dbnd]Se, Te)

The investigation of the structural, electronic, optical and thermoelectric properties of Ag3XY2 (X = Cu, Cd, Zn; YSe, Te) with full potential linearized augmented plane wave (FP-LAPW) method has been carried. To get accurate bandgap values the modified Becke-Johnson (mBJ) exchange potential was applied. Two materials Ag3CuSe2 and Ag3CuTe2 have band gap values of 0.62 eV and 0.53 eV. TDOS plot of these materials gives the contribution of each element (Ag, Cu, Se/Te) in VBM and CBM. The optical properties found that Ag3CuTe2 has higher optical conductivity than Ag3CuSe2 and also has a high absorption coefficient. Thermoelectric properties were calculated and it is observed that the numerical value of Seebeck coefficient of Ag3CuSe2 is higher than Ag3CuTe2 at room temperature. But from the calculation of the figure of merit (ZT), we concluded that Ag3CuTe2 has high value of ZT than Ag3CuSe2 in both p−type and n−type regions. So, Ag3CuTe2 can be used as the best thermoelectric material in both p−type and n−type as compared to Ag3CuSe2.

A DFT Investigation for structural, electronic, optical, and elastic properties of inorganic oxide perovskites CsXO3 (X = Ti, Mn, Cu) for photosensitive applications

The investigation of inorganic oxide perovskites, specifically CsXO3 (X = Ti, Mn, Cu), has been carried out utilizing density functional theory (DFT) to gain deeper insights into their structural electronic, optical, and elastic attributes. The calculated band gaps for CsTiO3, CsMnO3 and CsCuO3 are determined to be 1.68 eV, 3.26 eV, and 4.62 eV, respectively, while the lattice parameters are measured at 4.098 Å, 3.987 Å, and 4.059 Å. Our findings indicate that CsMnO3 and CsCuO3 possess moderate-sized, indirect band gaps, showcasing potential for enhanced conductivity. And CsTiO3 shows direct band gap. Additionally, CsTiO3 and CsCuO3 exhibit ductile and anisotropic behavior, as evidenced by both Poisson's ratio and the anisotropic factor. And CsMnO3 shows brittle nature. The anisotropic factors are 2.14 for CsTiO3, 1.99 for CsMnO3, and 1.89 for CsCuO3, whereas the Poisson's ratios are measured at 0.45, 0.34, and 0.49, respectively. Notably, CsTiO3 demonstrates significant photovoltaic activity within the visible spectrum, accompanied by a high optical conductivity and absorption coefficient, positioning it as a promising material for solar cell applications. The favorable attributes of CsTiO3 suggest its potential suitability for integration in optical and electronic devices.

Effect of metal (Cr, Sr, Ag, Cu) doping on the performance of lead-free RbSnI3 based perovskite solar cells: A theoretical approach

Perovskite solar cells based on lead have witnessed unprecedented growth over the past decade, achieving an impressive power conversion efficiency (PCE) of 26.1%. However, lead toxicity remains a concern for commercialization. In order to resolve the matter, scientists have been investigating alternative materials; in this context, rubidium-based lead-free perovskites like RbSnI3 may be a promising alternative because it has a high optical conductivity and absorption coefficient. Density Functional Theory (DFT)-based first-principles studies are used in this work to examine the effect of metal doping (specifically Cr, Sr, Ag, and Cu) on the optoelectronic and structural characteristics of orthorhombic RbSnI3 perovskite. In addition, we conducted a comprehensive study to investigate the impact of metal doping on the formation energy, structural stability, and HOMO–LUMO energy levels of RbSnI3 perovskite. Introducing transition metal cations (Cr2+, Ag+, and Cu+) at the Rb site results in a flat band in the conduction band region, transforming the RbSnI3’s indirect band gap into a direct one and significantly affecting the optoelectronic properties. The DFT results are then integrated into the Solar Cell Capacitance Simulator (SCAPS-1D) to estimate the effectiveness of the modeled device. The Cu-doped RbSnI3 device exhibits the highest PCE of 20.2%. Furthermore, Ag and Cu doping in RbSnI3 increases bond length, which reduces exciton binding energy and helps with charge carrier generation.

Generation of Q-switched and mode-locked pulses in erbium-doped fiber ring laser using saturable absorption of Ti2SnC

MAX phase materials have garnered significant attention due to their corrosion resistance, impressive antioxidation and high electrical and optical conductivity. One such material, Titanium Tin Carbide (Ti2SnC), has demonstrated notable nonlinear optical properties. The saturable absorption of Ti2SnC, embedded into a polyvinyl (PVA) film, was measured to assess its potential. The Ti2SnC -PVA film exhibited a calculated modulation depth of 7.8%. In the context of practical applications, the Ti2SnC-PVA film was employed as a saturable absorber (SA) in an Erbium-doped fiber laser (EDFL) cavity. This configuration enabled the generation of stable Q-switched and mode-locked pulse trains. Q-switched operation occurred in a pump power range of 51.67 mW–83.83 mW, reaching a peak pulse energy of 110.94 nJ. Transitioning to mode-locking operation, the laser cavity demonstrated efficiency in the pump power range of 105.27 mW–196.39 mW. At a pump power of 196.39 mW, the fiber laser cavity achieved its highest pulse energy of 5.42 nJ, characterized by a pulse width of 2.32 ps and a pulse repetition rate of 1.825 MHz. These results highlight the promising potential of Ti2SnC-PVA thin film as a cutting-edge material for applications in pulsed laser systems. The material's excellent nonlinear optical properties make it a compelling candidate for advancing the field of pulsed laser technology.