High Optical Absorption Research Articles

Structural, electronic, optical, mechanical, and phononic bulk properties of tetragonal trirutile antimonate MSb2O6 (M = Fe, Co, Ni, or Zn): a first-principles prediction for optoelectronic applications

Abstract This work does an extensive analysis of the optoelectronic and mechanical properties of the tri rutile structure type 3d transition metal Antimonate MSb2O6 (M = Fe, Co, Ni, or Zn), for the first time, utilizing the pseudo-potential plane wave approach within the density functional theory framework. When calculating the structural, optical, and mechanical properties, the exchange–correlation interactions were studied using the GGA-PBE functional, whereas when computing electronic, it is analyzed using the HSE06 hybrid functional. The equilibrium lattice parameters exhibit good agreement with the available experimental results. The electronic properties were estimated using the GGA-PBE and HSE06 functionals. Based on the calculated electronic properties with the GGA-PBE functional, the FeSb2O6, CoSb2O6, and NiSb2O6 materials exhibit metallic behavior with energy gap values of 0 eV, while ZnSb2O6 is a semiconductor with a narrow direct band gap (Γ–Γ) of 0.5 eV. Furthermore, the computed band gaps using the HSE06 functional are 0 eV, 0 eV, 1 eV (Γ–Γ), and 4 eV (Γ–Γ) for FeSb2O6, CoSb2O6, NiSb2O6, and ZnSb2O6, respectively. Density of states diagrams were used to gain deeper insights into the characteristics of the energy bands. The optical properties of these compounds, such as the dielectric function, energy loss function, conductivity, reflectivity, refractive index, and absorption coefficient were investigated over the energy range of 0 to 40 eV. The materials exhibited a high absorption coefficient and a significantly low reflectivity within the UV–vis energy spectrum. The negative cohesive energy Ecoh implies the chemical (thermodynamic) stability of the trirutile MSb2O6 (M = Fe, Co, Ni, or Zn). Mechanical stability is confirmed by applying the Born stability criteria using elastic constants (Cij). The absence of imaginary frequencies in the phonon spectrum calculations confirms the dynamic stability of the studied compounds. These results are consistent with previous experimental research on these materials in photocatalysis and gas sensor applications. On the other hand, these compounds possess exceptional high and broad optical absorption UV range, making them suitable for use in next-generation ultraviolet photodetectors.

Investigation of optoelectronic, mechanical and thermodynamic properties of cubic perovskite FrBCl3 (B = Zn, Cd) in approach of density functional theory

Lead-free cubic metallic halide perovskite (MHP) compounds, FrBCl3 (where B = Zn, Cd), have been evaluated using first-principles density-functional theory (DFT). Both FrZnCl3 and FrCdCl3 satisfy the stability conditions determined by their tolerance and octahedral factors. These materials demonstrate the characteristics of indirect band gap semiconductors, and their high optical absorption coefficients create promising opportunities for the advancement of optoelectronic devices. The elastic properties of both perovskites indicate robust mechanical stability, while their ductility, flexibility, and stiffness suggest potential for thin film fabrication. Furthermore, the Debye temperature profile underscores the thermal stability of these compounds. This computational study reveals coherent relationships among their structural, electronic, optical, mechanical, and thermodynamic properties. Consequently, these materials may offer exciting applications in nuclear medicine, X-ray imaging, and a variety of optoelectronic devices.

Fabrication of a Photocathode Based on Silver Iodide/Poly-2-Aminothiophenol with High Optical Absorbance Related to Intercalated Iodide Ions for Hydrogen Generation from Wastewater Without a Sacrificial Agent

Fabrication of a Photocathode Based on Silver Iodide/Poly-2-Aminothiophenol with High Optical Absorbance Related to Intercalated Iodide Ions for Hydrogen Generation from Wastewater Without a Sacrificial Agent

Ultrahigh carrier mobility and anisotropy of the layered semiconductor ATiN2 (A = Ca, Sr and Ba)

Semiconductors with a suitable band gap and high carrier mobility are highly desirable in the electronics, optoelectronic and photovoltaic applications. The mechanical, electronic, optical and transport properties of the layered nitrides ATiN2 (A = Ca, Sr, and Ba) have been systematically studied by theoretical calculations. These nitrides show good ductility with moderate moduli, larger Poisson's ratio than 0.26 and Pugh's modulus ratio exceeding 1.75. CaTiN2 and SrTiN2 are direct bandgap semiconductors, while BaTiN2 is an indirect bandgap semiconductor, showing suitable band gaps (1.54–1.78 eV) and band edge positions for optoelectronic and photocatalytic water-splitting applications. More intriguingly, they possess superhigh carrier mobility with remarkable anisotropy. Particularly, the in-plane electron mobility reaches an ultrahigh order of 104 cm2V−1s−1, whereas those along the out-of-plane direction are almost zero. In addition, the hole mobilities are also very large along the in-plane direction and the anisotropic ratios are as high as about 30 for all these nitrides. Furthermore, these ATiN2 nitrides exhibit high optical absorption coefficients (∼105 cm−1) and lower exciton binding energies. Due to the suitable band gaps and band alignments, ultrahigh carrier mobility and huge anisotropy, excellent visible light absorption performance, the ATiN2 nitrides will be promising candidate semiconductors in electronics, optoelectronic, photovoltaic and photocatalytic applications.

The effect of ultrasonic waves on the structure, morphology, and thermal conductivity of graphene oxide as nanofluids for direct absorption solar collector application

This research aims to explore how ultrasonic waves affect the structure and morphology of graphene oxide (GO) as a nanofluid, influencing its thermal conductivity (TC), stability, and photo-thermal conversion properties. GO was rapidly synthesized under ultrasonic bath irradiation using modified and improved Hummers' methods. Ultrasonic irradiation creates different structural and morphological defects in the GO that depend on the sonication time. The relationship between the exposure time to ultrasound and the creation of structural and morphological defects in graphene oxide nanosheets was investigated using UV–Vis, FTIR, Raman spectroscopies, AFM, and TEM analysis. The study examined how the structure and morphology of graphene oxide nanosheets affect the thermophysical and photo-thermal conversion properties of nanofluids by comparing heat transfer and stability. The simultaneous characterizing of the structure and morphology indicates that TC and stability are related to the sonication time. Indirect sonication with low intensity can carefully control the oxidation reaction of GO. Sonication for 30 min creates GO nanosheets that yield stable nanofluids with a 32.31 % enhancement in TC, with no extra treatment needed. This particular nanofluid has excellent photo-thermal conversion properties thanks to its high optical absorption, good stability, and thermal conductivity. This can increase the solar-thermal conversion efficiency (η) up to 72.5 %, making it a promising candidate for use as the working fluid in direct absorption solar collectors (DASCs)

Structural, electronic, optical and thermoelectric properties of FrSnI3-xClx (X=0, 1, 2, 3) perovskites using the TB-mBJ approach

Mixed halide inorganic perovskites represent a significant advance in energy conversion materials, with research on these materials paving the way for more sustainable and accessible energy solutions. In this work we investigated the effects of chlorine atom substitution on the structural, electronic, optical and thermoelectric properties of mixed halide perovskites FrSnI3-xClx (x=0, 1, 2, 3). The FP-LAPW approach within the Wien2k package has been employed, using the modified Becke-Johnson potential (TB-mBJ) for the exchange correlation functionals. For FrSnI3 and FrSnCl3 the calculated lattice parameters are in good agreement with theoretical results.The formation energies calculated for FrSnI3-x Clx (x = 0, 1, 2, 3) confirm the thermodynamic stability of all these materials. Analysis of the electronic properties, including partial density of states (PDOS), total density of states (TDOS) and band structures, indicates that these materials exhibit p-type semiconductor behaviour with direct band gaps ranging from 1.169 to 1.953 eV. In terms of optical properties, the FrSnI3-xClx compounds exhibit high optical absorption (α(ω) > 104 cm−1) in the visible region. The broad absorption range extends from visible to ultraviolet energy. The low reflectivity values observed (below 30%) and their minimal energy loss suggest potential applications in optoelectronic devices. The thermoelectric properties of these materials were also studied over a temperature range of 100 to 950 K. They exhibit high Seebeck coefficients, high electrical conductivity, and low thermal conductivity. Notably, at room temperature, FrSnI2Cl and FrSnICl2 show the highest figures of merit, reaching 1.31 and 0.61, respectively, demonstrating their high efficiency for thermoelectric devices

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.

Ab-initio investigation of structural, electronic, thermoelectric and optical properties of Full-Heusler X2MnB (X = Ti, Zr) for energy harvesting applications

In this manuscript comprehensive first-principles calculations have been presented for Full-Heusler X2MnB (X = Ti, Zr) compounds. This work includes detailed observations of the structural stability, origin of the transport phenomenon, optical properties, and electronic response. Structural parameters support the previous findings by confirming structural stability in the non-magnetic phase. Ti2MnB (Zr2MnB) valence band maxima and conduction band minima have bandgaps of 0.217 (0.301) eV and 0.181 (0.209) eV for PBE-GGA (mBJ) approximations which lie between L-L symmetry points. Due to the comparative measurements of the two states, the DOS results show that the Ti1/Zr1, Ti2/Zr2 Mn eg, and t2g states mainly contribute to the valence band region for Ti2MnB and Zr2MnB alloys, confirming their ionic nature. The computation of the overall electronic parameters’ reveals semiconducting nature. Thermoelectric properties have been calculated as a function of temperature in the 100–1200 K range. The positive values of Seebeck coefficients specify p-type character of X2MnB While at 300 K, Zr2MnB and Ti2MnB showed the highest Seebeck coefficients, measuring roughly values of 268 (µK/V) and 243 (µK/V), respectively. These values suggest that the material exhibits high thermoelectric performance. Though high optical absorption coefficient and low reflectivity in the visible and ultra violet regions, confirms use of these materials in solar cell applications. These findings suggest that material holds great potential for use in thermoelectrical applications which can support in upcoming experimental considerations.

Strain engineering of the structural, electronic, and optical properties of phosphorene‐like ZnS ceramic nanolayers: Density functional theory study

AbstractStrain engineering is a powerful technique for controlling the performance of semiconductor ceramic systems. In this article, the effect of strain engineering, specifically biaxial compressive and tensile strains, on the bonding characteristics, structure, electronic, and optical properties of nonplanar phosphorene‐like (NPP) ZnS ceramic nanolayers was investigated using density functional theory. It was observed that this ceramic exhibits greater stability under significant tensile strains. The structural stability of NPP‐ZnS ceramic, both with and without biaxial strain, was confirmed by its negative formation energy. Biaxial strain strongly influences the electronic band structure of NPP‐ZnS ceramic nanolayers, leading to a transformation from a direct band gap to an indirect gap under tensile strain. Additionally, the bandgap decreases under compressive strain, while it slightly increases under tensile strain. Various optical properties, including refractive index, extinction coefficient, absorption, reflectivity, optical conductivity, and optical susceptibility, were calculated. Biaxial compressive and tensile strains alter the optical properties, shifting them to higher or lower frequencies. NPP‐ZnS ceramic nanolayers exhibit high optical absorption in the UV range, which can be further enhanced by biaxial strain. Furthermore, under increasing compressive strain, the absorption edge moves toward higher energies. This improvement in optical absorption expands the potential applications of NPP‐ZnS ceramic nanolayers in optoelectronic devices.

WO3/Cu2O-CuO and WO3/Au/Cu2O-CuO heterojunctions photocatalysts for self-cleaning and photocatalytic degradation of organic pollutants applications

In this work, a high-performance WO3/Au/Cu2O-CuO heterojunctions was deposited via dc reactive magnetron sputtering, which displayed superhydrophilicity conversion and superior photocatalytic performance for the degradation of methylene blue. WO3, WO3/Cu2O-CuO, WO3/Au and WO3/Au/Cu2O-CuO heterojunctions were sputtered on precleaned glass and Si(100) substrates. The chemical composition, crystal structure, surface morphology, optical absorption, water contact angle and photocatalytic activities of the prepared single and multilayers films were examined to elucidate the correlation between structure and other properties. SEM revealed tiny small nanoparticles for WO3 film, close-packed nanoparticles for WO3/Cu2O-CuO multilayers and nanoparticles with more open structure for WO3/Au/Cu2O-CuO heterojunctions. The WO3/Au/Cu2O-CuO heterojunctions had the highest optical absorption. The estimated band gap values were 3.16, 3.08, 2.97 and 2.65 eV for WO3, WO3/Cu2O-CuO, WO3/Au and WO3/Au/Cu2O-CuO, respectively. The WO3/Cu2O-CuO, WO3/Au and WO3/Au/Cu2O-CuO became superhydrophilic after UV illumination. The remarkable photocatalytic activities of WO3/Au/Cu2O-CuO is attributed to the enhanced efficiency of separation for photogenerated hole–electron pairs.

Controlled two-step synthesis of n-type conjugated ladder polymers using a flow reactor

The coplanar backbone of conjugated ladder polymers (cLPs) enhances electron transfer and π-π interactions, making cLPs promising materials for various applications in organic electronics and optoelectronics. Nevertheless, the limited solubility and intricate synthetic processes for cLPs make it challenging to control their molecular weight and corresponding properties, and pose as significant obstacles to their widespread application. Here, an n-type cLP, PNDI-2BocL, was synthesized using a flow reactor for the first time, with controlled molecular weights. The polymerization reaction conditions to synthesize a precursor polymer, PNDI-2Boc, were first optimized in flow, followed by sequential ladderization in batch through the injection of an acid solution. The reaction time of polymerization was varied from 7.5 to 15 min, yielding soluble PNDI-2BocL with a number-averaged molecular weight (Mn) ranging from 9.8 to 54.0 kg/mol with a deviation of 11 %. Additionally, 15 min of polymerization and ladderization were successfully conducted in a single flow system sequentially for the first time. In the molecular weight-dependent studies, higher optical absorption at longer wavelengths, increased degrees of crystallinity, and higher electron mobilities in organic field-effect transistors (OFETs) were observed for higher molecular weight PNDI-2BocL. Our results highlight the importance of controlling the molecular weights of cLPs and demonstrate that the flow synthesis technique provides a viable solution for synthesizing soluble cLPs in a controlled, reproducible, and rapid manner.

Time Series Forecasting for Sparse Ring-shaped Array Photoacoustic Imaging Reconstruction

Abstract Photoacoustic computed tomography (PACT), which provides high optical absorption contrast and deep acoustic penetration, plays an important role in non-invasive biomedical imaging area. As the decrease of array elements, the reconstructed image suffers from severe artifacts. Recent studies utilize deep learning methods to improve the imaging quality of PACT based on image network design, but few were reported with raw data. To address this issue, this paper proposes a Wave to Wave Convolution Gate Recurrent-Net (WWCG-Net) to reconstruct photoacoustic image based on time series acoustic signal prediction. Simulation and experiment results show the superiority of our method compared with linear interpolation (LI) and eXtreme Gradient Boosting (XGBoost) in term of suppress artifact and improve resolution.

Tuning the optoelectronic properties of graphene monoxide by electric field, strain and heterostructure with Cd[formula omitted] ([formula omitted]=S, Se or Te)

Hydrogen production via photocatalytic water splitting has become a promising technique for developing clean and sustainable energy system. Low-dimensional carbon-based materials are under focus to develop high efficiency visible-light photocatalysts. Among the various 2D graphene-based materials, graphene oxides (GO) attracted attention in recent years. Recently identified GO such as graphene monoxide (GMO) shows promising electronic structure characteristics such as direct band gap behavior, high optical absorption, and well-dispersed band edges to use them in higher efficiency optoelectronic applications. Nevertheless, its valence band edge is distant from the water oxidation potential, and band gap value exceeds the ideal band gap required to effectively harvest solar energy, which minimizes its practical application in photocatalytic water splitting. Here, using hybrid density functional theory calculations, we are exploring the effect of applied electric field/strain on the photocatalytic water splitting and photovoltaic properties of GMO. We found that even after applying an electric field or strain, GMO retains the desirable direct band gap behavior, well-dispersed bands at the band edges, and high optical absorption in the visible range. Further, the band alignment analysis suggests that the application of compressive strain enhances the efficiency of photocatalytic water splitting by straddling the band edges with water redox potentials. Additionally, we explored the optoelectronic properties of GMO by designing its heterostructure with CdS, CdSe, and CdTe monolayers. Remarkably, the studied heterostructures demonstrated superior optical absorption in the visible spectrum and a low recombination rate of charge carriers by separating them across different layers with type-II band alignment; suggesting that these heterostructures will be efficient candidates for visible energy photocatalytic water splitting and higher-efficiency solar cells.

Tellurene Polymorphs: A New Frontier for Solar Harvesting with Strong Exciton Anisotropy and High Optical Absorbance

Tellurene Polymorphs: A New Frontier for Solar Harvesting with Strong Exciton Anisotropy and High Optical Absorbance

Key parameters to optimize the photothermoelectric effect of thermoelectric materials

Recently, photothermoelectric effect of thermoelectric materials has been hotly explored to develop self-powered and large bandwidth photodetectors working at ambient conditions. However, the key parameters for optimized photothermoelectric effect are still elusive. Here, based on the two-temperature model under static condition, we theoretically studied the key parameters to optimize the photothermoelectric performance of thermoelectric materials. Results verify that when the incident electromagnetic wave only generates electronic intra-band excitation, there is an ideal carrier concentration to optimize the photothermoelectric voltage; when the wavelength of a detected electromagnetic wave can resonantly excite quasi-particle (like phonons) except electrons, the photothermoelectric voltage can be enhanced significantly around the resonant wavelength regime; and when the electronic inter-band transition can be excited by an electromagnetic wave, photothermoelectric voltage is significantly increased due to the high optical absorption. As an example, the theoretical dependence of the photothermoelectric voltage of SnSe on wavelength is in line with the experimental result. This work elucidates the crucial parameters of thermoelectric materials to achieve the ideal photothermoelectric performance.

A novel approach of polychiral single walled carbon nanotubes functionalization for heterojunction solar cell

This study introduces an innovative method for functionalizing polychiral single-walled carbon nanotubes (f-SWCNTs) by depositing thin films onto n-type crystalline silicon (n-Si), thereby creating efficient heterojunction solar cells. The approach capitalizes on the effective charge separation facilitated by the built-in potential resulting from the functionalization of polychiral SWCNTs, leading to enhanced electron transfer from f-SWCNTs to Si driven by functional groups. The resulting f-SWCNT/Si heterojunction device demonstrates remarkable performance, attributed to the high optical absorption and improved charge separation and transfer mechanisms of the f-SWCNT film. Moreover, by adjusting the concentration of f-SWCNTs, the film properties and overall device performance have been customized, achieving a notable power conversion efficiency of 12 %. These discoveries serve as a foundation for the advancement of highly desirable, efficient, cost-effective, and broadband high-performance f-SWCNT/Si heterojunction solar cells

Effect of deposition cycle and annealing on the structural, optical, electrical, and photoluminescence properties of SnS films obtained from rapid S-SILAR technique

AbstractIn this paper, we present an optimized procedure for depositing SnS thin films using the rapid S-SILAR technique. We also analyze the effects of deposition cycles and post-deposition annealing on various film properties. XRD analysis indicates the presence of orthorhombic and cubic phases in the films. Energy dispersive X-ray analysis confirms near-optimal stoichiometry. SEM images depict the growth of closely spaced spherical granules. High optical absorption is observed in the mid-visible to NIR region, with the absorption edge shifting towards the NIR region after annealing. The bandgap values range from 1.6 eV to 1.9 eV, which is ideal for photovoltaic applications. PL spectra show three clusters of peaks corresponding to red and green emissions. Hall measurements confirm that both the as-deposited and annealed SnS films exhibit p-type conductivity, with a hole concentration on the order of 1015 cm−3.

High performance metal halide Cu–Ag–I–Cl alloys for photodegradation

Ag-based semiconductors have stimulated great interest as promising photocatalysts due to their high optical absorption. While exhibiting excellent photocatalytic activity, they suffer from poor stability. On the other hand, CuI is an air-stable material with excellent optical absorption and bandgap of 3 eV, and can be an alternative to the photosensitive and expensive Ag halides for photocatalytic applications. In this study, alloying strategy was used to prepare Cu–Ag–I–Cl alloys with wide compositions Cu1-xAgxI1-xClx (0 ≤ x ≤ 1), and their structural, optical and photodegradation properties were evaluated. X-ray diffractionmeasurements revealed the single-phase solid solution formation with systematic phase transition, from γ-phase to β-phase upon alloying of AgCl into CuI, infer the coordination effects associated with atomic size. The optical band gap has shown significant modifications with alloying, with minima of 2.65 eV at x = 0.25. The Malachite green dye photodegradation under UV-light exposure was evaluated for various Cu1-xAgxI1-xClx alloy samples at different solution pH. Compared to pure CuI, alloying of AgCl into CuI has significantly enhanced photodegradation, with the highest degradation efficiency of 88 % at 40 minutes and pH of 3 for x = 0.25. Further, the Cu1-xAgxI1-xClx alloy has demonstrated significant photodegradation (54 % at 100 minutes) of ofloxacin, indicating that they can be potential for other stubborn organic pollutants removal from wastewater. Through quenching experiments, the O2•− reactive oxygen species were identified as primarily responsible for the photodegradation in this system. The origin of high photodegradation performance in Cu–Ag–I–Cl alloy system is attributed to the configurational entropy and surface plasmon resonance of nonstoichiometric Ag on the surface. The significant efficiency achieved with an alloying strategy involving functional halides could open a novel path to develop photocatalysts alternative to complex heterogeneous and multicomponent methods.

Optoelectronic, thermoelectric and 3D-Elastic properties of lead-free inorganic perovskites CsInZrX6 (I, Cl and Br) for optoelectronic and thermoelectric applications

Halide perovskite materials have recently gained worldwide attention since they offer a new cost-effective way to generate renewable and green energy. In the current work, the structural, electrical, elastic, optical and thermoelectric properties of new perovskites CsInZrX6 (I, Cl and Br) were explored by density-functional theory (DFT). The results indicated that the computed lattice parameters agree really well with the current experimental and theoretical results. Moreover, the band structure profile strongly suggests that the compounds exhibit a semiconducting nature with a direct band gap. The analysis of their optical properties reveals that the perovskites possess a low reflectivity (below 23%) and a high optical absorption coefficient (106 cm−1). This is also supported by the evaluation of their calculated elastic constants and their related parameters in cubic structure which show that these compounds are brittle, mechanically stable and possess covalent bonds. On the other hand, in addition to exhibiting outstanding optoelectronic and mechanical characteristics, CsInZrCl6 also possesses dynamical stability, making it a promising candidate for application in various optoelectronic devices except for solar cells due to its relatively large bandgap. Furthermore, the BoltzTraP software was used to compute the materials’ thermoelectric properties, with the computed values of the figure of merit (ZT) for CsInZrBr6, CsInZrCl6 and CsInZrI6 being 0.76, 0.73 and 0.725, respectively. This is also a strong indication that these materials are potential for thermoelectric applications.

Narrow bandgap two-dimensional Nb2SiTe4 as broadband saturable absorber for optical switch

Nb2SiTe4 is a novel narrow-bandgap (∼0.39 eV) two-dimensional material with a high optical absorption coefficient, high carrier mobility, and outstanding air stability, which shows great application potential in broadband optical switches. In this study, high-quality layered Nb2SiTe4 nanosheets were efficiently fabricated by the mechanical exfoliation method, and the basic characterizations were carried out comprehensively. Nondegenerate pump-probe technology was implemented to systematically explore the photocarrier dynamics in the Nb2SiTe4 nanosheets, which exhibit the ultrafast recovery time of Nb2SiTe4 (∼0.3 ps). Furthermore, broadband passively Q-switched lasers operating at 1.0, 2.0, and 2.8 μm with the shortest pulse width of 380, 549, and 218 ns were achieved based on Nb2SiTe4 saturable absorber. This work demonstrates the significant advantages of an optical switch based on Nb2SiTe4 saturable absorber, including a narrow output pulse width, wide working bandwidth, high damage threshold, excellent oxidation resistance, and a straightforward synthesis method, which underscore the immense potential of Nb2SiTe4 broadband optical switches in applications involving mid-infrared lasers.