Tunable Band Gap Research Articles

Growth Phenomena and Bandgap Shift in Melt‐Grown β‐(InxGa1−x)2O3 Alloys

β‐Ga2O3 is an emerging ultra‐wide bandgap semiconductor with great promise for power electronics and optoelectronics. Alloys in the In2O3‐Ga2O3 system are interesting for optoelectronic applications, particularly where bandgap tuning is desirable. Herein, β‐(InxGa1–x)2O3 alloys with target compositions x = 0.025 or 0.10 are grown from the melt using the Czochralski and vertical gradient freeze techniques. Growth with 10 mol% In yields only small, needle‐like crystals, while 2.5 mol% In allows growth of centimeter‐sized single crystals. A substantial degree of indium segregation is unveiled by spatial measurements of lattice parameters and the bandgap. The bandgap decreases by a maximum of 0.28 eV in the case of the highest In content crystals. Z‐contrast transmission electron microscopy confirms a solely octahedral coordination of In in the β‐Ga2O3 lattice. With indium concentrations higher than 2.5 mol%, samples contain micron‐scale voids that impart a dark coloration. All measured crystals are electrically conductive, with carrier concentrations varying 1016–1017 cm−3 depending upon the location of the sample in the growth. Lastly, a unique luminescence with unknown origin centered around 2.0 eV is revealed by photoluminescence spectroscopy.

Promising 2D Carbon Allotropes with Intrinsic Bandgaps Based on Bilayer α‐Graphyne

2D carbon allotropes with moderated electronic bandgaps are highly desirable for next‐generation carbon‐based nanoelectronics beyond graphene. Herein, the structural and electronic properties of bilayer α‐graphyne have been systematically investigated by using first‐principles calculations. Consequently, in addition to typical van der Waals (vdW) stacks of single‐layer α‐graphyne, new 2D carbon allotropes with purely sp2 or sp3 hybridizations can be achieved, arising from the absence of intralayer acetylene linkages during structural relaxation. Compared to the Dirac semimetallic behavior of monolayer α‐graphyne, the electronic structure of vdW bilayer α‐graphyne can be further modulated by stacking patterns, yet retains metallic characteristics. In contrast, intrinsic semiconducting characteristics can be observed in the proposed new 2D carbon allotropes with tunable bandgaps dependent on the in‐plane biaxial strain. Correspondingly, a pristine 2D carbon sheet with only sp2 hybridization exhibits a promising direct bandgap of 1.062 eV, while the sp3‐hybridized carbon network possesses an indirect bandgap of 1.708 eV, which can be further converted to the direct type under small compressive strains, implying great potential in future carbon‐based nanoelectronic applications beyond graphene. Also, this work provides a new approach for developing novel carbon allotropes via the vertical stacking of graphyne with acetylenic linkages.

Thermoelectric power generator module using n-type Sb₂S₃ and p-type Bi₂Te₃-coated cotton fabric for wearable device applications

Antimony trisulfide (Sb₂S₃), a binary metal chalcogenide, exhibits significant promise for energy conversion applications due to its tunable bandgap and exceptional stability under exposure to moisture and air, making it a strong candidate for thermoelectric applications. In this study, Sb₂S₃ was synthesized via co-precipitation method and subsequently coated onto cotton fabric using a formulated ink. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses confirmed its orthorhombic crystalline structure and nanorod-like morphology. Sb₂S₃ was found to possess an indirect bandgap of 1.70 eV in its amorphous phase and 1.52 eV in its crystalline phase. Fourier-transform infrared (FTIR) spectroscopy revealed characteristic peaks at 447 cm⁻1 and 568 cm⁻1, corresponding to the symmetric stretching vibrations of Sb-O and Sb-S bonds, respectively. Current-voltage (I-V) measurements indicated near-ohmic behavior with an electrical conductivity of 2 × 10⁻⁵ S/cm, while Hall effect measurements confirmed its n-type semiconducting nature. The thermoelectric evaluation of Sb₂S₃-coated cotton fabrics demonstrated n-type behavior, with the Seebeck coefficient increasing with temperature, reaching −185 μV/K at 293 K with a notable power factor of 6.845 × 10−4 nW/cmK2. The material also exhibited low thermal conductivity (0.077 W/mK) and an effusivity of 223.95 Ws1/2/m2K. For the first time, a thermoelectric device was successfully fabricated by combining Sb₂S₃ as the n-type material with Bi₂Te₃ as the p-type material. This device, integrated into a wearable hand band, demonstrated an output voltage of 4.7 mV under a temperature difference of approximately 4 °C, highlighting its significant potential for low-power applications in wearable technology. The successful integration of these materials into a flexible substrate underscores their viability in next-generation thermoelectric energy harvesting devices.

Inkjet printing of mixed layers comprising multinary semiconductor quantum dots and charge transport materials for light‐emitting diode displays

AbstractQuantum dots (QDs) are important luminescent structures with applications in wide‐color‐gamut displays requiring exceptional color reproducibility. Multinary semiconductor QDs are expected to serve as eco‐friendly materials to replace conventional QDs owing to the narrow spectral widths and tunable bandgaps of these QDs. However, the application of multinary QDs, which tend to exhibit defect‐related emissions, to QD light‐emitting diode (QLED) displays will require electroluminescence to be obtained from QLEDs incorporating inkjet‐printed emitting layers. The present work examines QLEDs exhibiting vibrant color emissions based on blue‐emitting Zn–Se–Te QDs, green‐emitting Ag–In–Ga–S QDs, and red‐emitting Ag–Cu–In–Ga–S QDs. Each such QLED contains QD emitting layers comprising a mixture of charge transport materials. The spectra obtained from these RGB QLEDs fabricated by spin‐coating show very high color purity. Passive matrix QLED displays incorporating these QDs are also fabricated by inkjet printing to demonstrate the high color purity that can be obtained from multinary QDs in displays. In conjunction with passive matrix driving, these displays produce clear moving images with vibrant electroluminescence originating from the multinary QDs. The present results indicate that these QDs have significant potential for utilization in wide‐color‐gamut displays.

2D‐SnS‐Embedded Schottky Device with Neurotransmitter‐Like Functionality Produced Using Proximity Vapor Transfer Method for Photonic Neurocomputing

AbstractNeuromorphic computing, which involves the creation of artificial synapses capable of mimicking biological brain activity, has intrigued researchers in the field of artificial intelligence (AI). To advance neuromorphic computing, a highly efficient 2D material‐based artificial synapse capable of performing logical and arithmetic operations must be developed. However, fabricating large, uniform films or high‐quality structures of 2D materials remains challenging because of their multistep and complex fabrication processes. In the present study, to produce large (Ø ≈ 3 in.), uniform, transparent neuromorphic devices, a novel single‐step approach called proximity vapor transfer (PVT) that utilizes van der Waals (vdW) materials is employed. This single‐step technique, which involves the fabrication of vdW materials on various substrates (glass, ITO, AZO, Mo, and Cu), allows control of the thickness and bandgap tunability. The Schottky device developed via the PVT method using vdW SnS with neurotransmitter (acetylcholine)‐like functionality emulates biological synapses and exhibits photoelectronic synaptic behavior with wide‐field‐of‐view synaptic plasticity. In addition, logic gate operations (NOT, OR, AND), reward‐cascade neurotransmission, and imaging can be performed using 3 × 3 arrays of the device. This study represents a significant step toward the development of transparent and large‐area synaptic devices, which are crucial for advancing AI applications.

Origin and Potentialities of the Selective Host‐Matrix Effect in Hydrogenated III‐V‐N Alloys.

AbstractIn a previous study, puzzling experimental results regarding the neutralization of N effects on the bandgap energy in the hydrogenated In0.21Ga0.79As0.975N0.025 alloy were explained by theoretical investigations revealing the occurrence of a novel phenomenon: thermal annealing changes the InGaAs host‐matrix by making it able to exert a selection of the N–H complexes responsible of the N neutralization. In view of technological applications of this effect, the underlying selective host‐matrix model was carefully checked here by theoretically investigating InGaAsN alloys of different compositions ranging from Ga‐rich to In‐rich. As a most important result, such an extensive investigation inspired a comprehensive explanation of the origin of the host‐matrix effect which clarifies how the effect works, firmly establishes its occurrence, gives indications for a bandgap tuning based on a matrix design, sets conditions for its extension to other III‐V‐N alloys and suggests ways to induce fine changes of the alloy mechanical behavior.

Electromagnetically tunable spin-valley-polarized current via anomalous Nernst effect in monolayer of jacutingaite.

Monolayer jacutingaite (Pt2HgSe3) exhibits remarkable properties, including significant spin-orbit coupling and a tunable band gap, attributed to its buckled honeycomb geometry and the presence of heavy atoms. In this study, we explore the spin- and valley-dependent anomalous Nernst effect (ANE) in jacutingaite under the influence of a vertical electric field, off-resonance circularly polarized light (OCPL), and an antiferromagnetic exchange field. Our findings, within the low-energy approximation, reveal the emergence of a perfectly spin-polarized ANE with the application of appropriate OCPL and a perfectly valley-polarized ANE under an antiferromagnetic exchange field. Leveraging the robust spin-orbit coupling inherent in monolayer jacutingaite, our study highlights the potential to attain perfectly spin-valley-polarized Nernst currents across a wide range of Fermi energy levels by combining these fields in pairs with a suitable strength. The findings can be used for the development of spin-valley-based optoelectronic devices.&#xD.

Tunable Optical Properties and Relaxor Behavior in Ni/Ba Co-Doped NaNbO3 Ceramics: Pathways Toward Multifunctional Applications

In this study, Ni/Ba co-doped NaNbO3 ceramics (NBNNOx) were synthesized using a solid-state method to explore the effects of Ni2+ and Ba2+ ion substitution on the structural, optical, and dielectric properties of NaNbO3. X-ray diffraction (XRD) confirmed that the ceramics retained an orthorhombic structure, with crystallinity improving as the doping content (x) increased. Significant lattice distortions induced by the Ni/Ba co-doping were observed, which were essential for preserving the perovskite structure. Raman spectroscopy revealed local structural distortions, influencing optical properties and promoting relaxor behavior. Diffuse reflectance measurements revealed a significant decrease in band gap energy from 3.34 eV for undoped NaNbO3 to 1.08 eV at x = 0.15, highlighting the impact of co-doping on band gap tunability. Dielectric measurements indicated relaxor-like behavior at room temperature for x = 0.15, characterized by frequency-dependent anomalies in permittivity and dielectric loss, likely due to ionic disorder and structural distortions. These findings demonstrate the potential of Ni/Ba co-doped NaNbO3 ceramics for lead-free perovskite solar cells and other functional devices, where tunable optical and dielectric properties are highly desirable.

Epitaxial SiGeSn grown on Si by ion implantation

We have formed SixGe1−x−ySny compounds on Si substrates by ion implantation and annealing and investigated their concentration profiles, crystallization, and optical properties. Ge and Sn ions were implanted in the range (2.5–10) × 1016 Ge/cm2 at 65 keV, and (1.0–4.0) × 1016 Sn/cm2 at 100 keV, resulting in a peak implant dose at a depth of 50 nm for both species. Epitaxially regrown SixGe1−x−ySny layers (110 nm thick) were produced with Ge and Sn contents that allowed bandgap tuning in the (0.88–1.1) eV range. Shifts in photoelectron binding energies (Si 2p, Ge 3d, and Sn 3d) were consistent with ternary compound formation. Sn segregation was observed for annealing temperatures ≥600 °C. A significant increase in the optical absorption coefficient (×104 cm−1 for λ = (800–1700) nm) was observed for SiGe, SiSn, and SiGeSn alloys, with SiGeSn having coefficients several orders of magnitude higher than for Si. Contributions of segregated Sn to these properties were observed. Metastable SixGe1−x−ySny layers were achieved, which may point to a promising route to mitigate Sn incorporation challenges for near-infrared detectors.

Transmission and Reflection Properties of Iron Pyrite-Epoxy Resin Composite for Electromagnetic Applications

This study examines the electromagnetic properties of a composite material composed of iron pyrite (FeS2) and epoxy resin, mixed in a 3:2 weight ratio to create a 10 cm3 cube. The research analyzes transmission and reflection coefficients and band gap parameters to determine its viability as an antenna substrate for electromagnetic wave applications. The composite displays a tunable band gap of 1.3 eV, enabling selective absorption and emission of electromagnetic radiation. The transmission coefficient achieved 90% throughout a frequency range of 1 GHz to 15 GHz, whilst the reflection coefficient was measured at 10%, significantly reducing reflecting losses. The epoxy resin binder was essential for preserving structural integrity and augmenting the dielectric characteristics of the composite, thereby raising transmission efficiency. UV-Vis spectroscopy showed an absorption value of 0.875% at the band gap, indicating efficient interaction with UV energy. The S21 transmission coefficient ranged from −10 dB to −80 dB, with a maximum of −40 dB at 6 GHz, indicating strong energy transfer capability for antenna applications. The S21 values exhibited negligible signal attenuation between 2 GHz and 7 GHz, indicating the material’s exceptional suitability for antenna substrates necessitating dependable transmission. The S11 reflection coefficient varied from −5 dB to −55 dB, with substantial decreases between 4 GHz and 14 GHz, when reflection decreased to −45 dB, signifying little signal reflection at essential frequencies. The results underscore the composite’s appropriateness for applications requiring high transmission efficiency, little reflection, and effective engagement with electromagnetic waves, especially as an antenna substrate. Measurements were performed using a vector network analyzer (VNA) to obtain the S11 and S21 characteristics, underscoring the material’s potential in sophisticated electromagnetic applications.

Continuously tunable negative pressure for engineering high-symmetry nanocrystalline phases

In this work, the phenomenon of strain induced by a mismatch in thermal expansion coefficients between a thin film and its substrate is harnessed in a new context, replacing the canonical planar support with a three-dimensional (3-D), nanoconfining scaffold in which we embed a material of interest. In this manner, we demonstrate a general approach to exert a continuously tunable, triaxial, tensile strain, defying the Poisson ratio of the embedded material and achieving the exotic condition of "negative pressure." This approach is hypothetically generalizable to materials of low modulus and high thermal expansion coefficient, and we use it here to achieve negative pressure in perovskite-phase CsPbI3 embedded within the cylindrical pores of anodic aluminum oxide membranes. Through controlled thermal hysteresis, the perovskite crystal structure can be continuously tuned toward higher symmetry when confined in a scaffold with pore size <40 nm, in contrast with the symmetry-reducing action of any other mechanical perturbation. We use this effect to control the octahedral rotation angle that is critical to the remarkable photovoltaic attributes of halide perovskites. Under hundreds of megapascals of apparent negative pressure, the bandgap tunability is observed to follow the same quantitative trend observed for hydrostatic positive pressure, exploring the negative pressure region and demonstrating the relative dominance of bond stretching effects over average octahedral rotation angle on electronic structure. This study reveals and quantifies the structural and electronic consequences of 3D tensile strain present by design and provides a framework for understanding adventitious strain present in all nanocomposite materials.

Analysis on future development of solar cells focusing on materials and devices

In recent times, solar cells have garnered significant attention due to their numerous advantages. These include continuously improving energy conversion efficiency, a simple solution preparation method, flexibility, lightweight design, wearability, suitability for ultra-lightweight space applications, and low-cost material components. Perovskite solar cells have achieved impressive efficiencies of over 25% by using high-quality perovskite films synthesized at low temperatures and by making advancements in compatible interface and electrode materials. Moreover, the stability of cells has become a major focus of research. This paper analyzes the development history, material system, device structure, challenges, and future development direction of perovskite solar cells. The unique photoelectric properties and tunable band gap of materials have made them a hot topic in the field of solar cells. In this paper, the basic characteristics and synthesis methods of perovskite materials are introduced before discussing the device structure, interface engineering, and stability of perovskite solar cells in detail. Finally, it prospects on the future development trend of perovskite solar cells.

Managing Edge States in Reduced-Dimensional Perovskites for Highly Efficient Deep-Blue LEDs.

Pure-halide reduced-dimensional perovskites, featuring large exciton binding energy and tunable bandgap, show great potential for high-efficiency deep-blue perovskite light-emitting diodes (PeLEDs). However, their efficiency, particularly in the low n-value phase domain ("n" represents the number of octahedral sheets), lags behind analogous perovskite emitters. Herein, it is demonstrated that the vibration of edge-dangling octahedra in the low n-value phase activates notorious exciton-phonon (EP) coupling, thereby deteriorating efficiency. To address this issue, an approach is reported to manage edge-state lattices by introducing tris(4-fluorophenyl) phosphine (TFP) ligands. Attributed to the large steric hindrance of TFP ligands and their strong binding affinity for edge-dangling octahedra, the edged-octahedral tilting reconstruction can effectively suppress lattice vibration and inhibit EP coupling. This strategy yields deep-blue emitting film with a spectral linewidth of 21nm and a photoluminescence quantum yield of 85% at low excitation densities. The resulting PeLEDs achieve deep-blue emission at 469nm, with a maximum luminance of 2,428cdm-2 and a maximum external quantum efficiency of 10.4%, marking them among the most efficient deep-blue PeLEDs reported. The strategy also showcases universality for higher n-value reduced-dimensional perovskites. It is believed that the observation, along with the edge-state management strategy, lays the groundwork for further advancements in reduced-dimensional perovskite optoelectronic devices.

Investigation of the physical properties and pressure-induced band gap tuning of Sr3ZBr3 (Z=As, Sb) for optoelectronic and thermoelectric applications: A DFT - GGA and mBJ studies

This study discusses the feasibility of diversifying the scope of application of lead-free Sr3ZBr3 (Z = As, Sb) as promising materials for their enhanced electronic, mechanical, optical, thermodynamic, and thermoelectric properties using first-principles calculation based on Density Functional Theory (DFT). Both compounds have cubic crystal structures, and both materials' dynamic stability is validated by the lack of negative frequencies in their phonon dispersion spectra. Besides ground state physical characteristics, we also examined the impact of hydrostatic pressure (0–21 GPa) on electronic, mechanical, and optical properties. The lattice parameters exhibit a linear decrease from 6.27 to 5.61 Å for Sr3AsBr3 and 6.45 to 5.71 Å for Sr3SbBr3 under increasing pressure, attributed to bond length reduction, which alters their physical properties. Initially observed direct band gap (Γ-Γ) of Sr3AsBr3 and Sr3SbBr3 were 2.35 and 2.30 eV using modified Becke-Johnson (mBJ) functional which reduces to 1.15 and 0.82 eV as the compounds go from 0 to 21 GPa pressure. This study reveals enhanced optical properties under pressure, with broader spectral response, increased sensitivity, and improved dielectric constant. Optical absorption and conductivity also shift toward lower-energy photons. The investigation further shows that the compounds show brittle to ductile transition under high pressure. Their ductility and anisotropy nature are further enhanced with pressure along with other mechanical features. The thermodynamic properties indicate their ability to withstand and perform well at high temperatures and pressures. Lastly, the thermoelectric properties of Sr3ZBr3 (Z = As, Sb) were assessed through electrical and thermal conductivity, Seebeck coefficient, power factor (PF), and figure of merit (ZT) as a function of temperature. Both compounds exhibit high PF and near-unity ZT. These findings underscore their potential as strong candidates for optoelectronic and thermoelectric devices, owing to their direct bandgap and exceptional properties.

Steering Nonlinear Chiral Valley Photons Through Optical Orbit–Orbit Coupling

AbstractTwo‐dimensional transition metal dichalcogenides feature a direct tunable bandgap and robust spin‐valley coupling, offering an additional valley degree of freedom for information carriers. While optical spin‐orbit coupling has traditionally facilitated valley manipulation, on‐chip control of nonlinear valley photons remains elusive. Here, the directional coupling of nonlinear chiral valley photons through optical orbit‐orbit coupling in monolayer tungsten disulfide at room temperature is demonstrated. The chirality of nonlinear valley photons is governed by the spin angular momentum of the pump light, adhering to nonlinear selection rules. Importantly, the coupling direction is controlled by the orbital angular momentum of the pump light, facilitated by the orbital momentum flux. This approach not only provides a novel method for manipulating the valley degree of freedom but also enhances the flexibility of directing valley photon emission and on‐chip routing. These developments hold promising prospects for advanced valley optoelectronic devices.

Active Photonic Glass for Hydrogen Generation.

Chirality is vital in many living species since it is responsible for structural iridescent coloration and plays a key role in light harvesting during natural photosynthesis. Developing photoactive materials with such chiral structures is a challenging but promising strategy for energy applications. Here, we describe a straightforward method to establish an active photonic glass obtained through the co-condensation oftetramethyl orthosilicate (TMOS) and titanium diisopropoxide bis(acetylacetonate) (TAA) dissolved in a liquid crystal formed from cellulose nanocrystalline (CNC). The inorganic glass maintains a long range of chiral nematic ordering, displaying iridescent colors characterized by a Bragg peak reflection. The reflected wavelengths are tuned all over the UV-visible range, demonstrating that the replica of the chiral nematic structure generates photonic properties. Incorporation of gold nanoparticles (Au NPs) into the films is further performed by impregnation/chemical reduction. We show that the charge carrier density and photocatalytic H2 generation were amplified when the photonic band gap edges matched the absorbance of the TiO2 and localized surface plasmon resonance (LSPR) of AuNPs. This photocatalytic glass with chiral nematic ordering and a tunable photonic bandgap paves the way for the development of metamaterials with new applications, such as asymmetric photocatalysis.

A DFT Study of Band-Gap Tuning in 2D Black Phosphorus via Li+, Na+, Mg2+, and Ca2+ Ions

Black phosphorus (BP) and its two-dimensional derivative (2D-BP) have garnered significant attention as promising anode materials for electrochemical energy storage devices, including next-generation fast-charging batteries. However, the interactions between BP and light metal ions, as well as how these interactions influence BP’s electronic properties, remain poorly understood. Here, we employed density functional theory (DFT) to investigate the effects of monovalent (Li+ and Na+) and divalent (Mg2+ and Ca2+) ions on the valence electronic structure of 2D-BP. Molecular orbital analysis revealed that the adsorption of divalent cations can significantly reduce the band gap, suggesting an enhancement in charge transfer rates. In contrast, the adsorption of monovalent cations had minimal impact on the band gap, suggesting the preservation of 2D-BP’s intrinsic electrical properties. Energetic and charge analyses indicated that the extent of charge transfer primarily governs the ability of ions to modulate 2D-BP’s electronic structure, especially under high-pressure conditions where ions are in close proximity to the 2D-BP surface. Moreover, charge polarization calculations revealed that, compared with monovalent cations, divalent cations induced greater polarization, disrupting the symmetry of the pristine 2D-BP and further influencing its electronic characteristics. These findings provide a molecular-level understanding of how ion interactions influence 2D-BP’s electronic properties during ion-intercalation processes, where ions are in close proximity to the 2D-BP surface. Moreover, the calculated diffusion barrier results revealed the potential of 2D-BP as an effective anode material for lithium-ion, sodium-ion, and magnesium-ion batteries, though its performance may be limited for calcium-ion batteries. By extending our understanding of interactions between ions and 2D-BP, this work contributes to the design of efficient and reliable energy storage technologies, particularly for the next-generation fast-charging batteries.

Wurtzite CuIn(SxSe1-x)2 Nanocrystals: Colloidal Synthesis and Band-Gap Engineering.

CuIn(SxSe1-x)2 nanocrystals as an emerging class of functional materials present huge potential for industrial applications; however, the synthesis of CuIn(SxSe1-x)2 nanocrystals remains a formidable challenge in achieving both tunable band gap and phase. Here, we reported a facile hot-injection method for synthesizing a family of wurtzite CuIn(SxSe1-x)2 nanocrystals, enabling manipulation of the S and Se contents across the entire compositional range (0 ≤ x ≤ 1). The obtained nanocrystals exhibit band gaps ranging from 1.21 to 1.58 eV, which vary depending on the S/Se ratios in the products. This approach can be readily extended to other scenarios involving chalcogenide nanomaterials, thereby facilitating the advancement of next-generation functional materials and applications.

Investigation of Structural, Electronic, Optical, and Photocatalytic Properties of new double perovskites Cs2InSbX6 (X = F, Cl) under Strain Effects

Inorganic halide perovskites, such as Cs₂InSbX₆ (X = F, Cl), have shown potential for next-generation solar cells and photocatalysis due to their light-capturing properties. However, concerns about stability and toxicity in lead-based perovskites drive the need for eco-friendly alternatives like antimony-based compounds. This study employed Density Functional Theory (DFT) calculations to explore how mechanical strain affects the electronic and optical properties of Cs₂InSbX₆. Without strain, Cs₂InSbF₆ and Cs₂InSbCl₆ exhibit bandgaps of 2.06 eV and 1.20 eV, respectively. We investigated how strain ranging from -5% to +5% influences these materials' performance in optoelectronic and photocatalytic applications. Notably, negative strain enhances absorption and quantum efficiency for both compounds, particularly Cs₂InSbCl₆, which shows superior absorption in the visible spectrum. Our findings suggest that Cs₂InSbCl₆, with a tunable bandgap and favorable optical characteristics under strain, is a promising candidate for environmentally friendly applications, including solar cells and photocatalysis.

First principle insight of CaBS[formula omitted] (B= Sn, Zr and Hf) chalcogenide perovskite as eco-friendly material for photovoltaics

Lead-free perovskite-type materials, renowned for their easy processing and tunable bandgaps, have emerged as a cost-effective alternative for fabricating high-efficiency tandem solar cells. Utilizing density functional theory (DFT) combined with the full-potential linearized augmented plane wave (FP-LAPW) method and the modified Becke-Johnson exchange potential (TB-mBJ), this study investigates the potential of CaBS3 (B = Zr, Hf, and Sn) compounds as promising absorbers for next-generation tandem applications. Our results demonstrate that CaBS3 compounds exhibit semiconducting properties with direct bandgaps. This study investigates the unique properties of CaBS3 perovskites, revealing their potential to enhance the efficiency of next-generation photovoltaic devices. Our findings demonstrate that CaZrS3 exhibits a remarkable Seebeck coefficient of up to 3200 μV/K, indicating superior p-type conduction and enhanced thermoelectric efficiency. Furthermore, the direct bandgaps and ambipolar conductive behavior of these materials position them as strong candidates for photovoltaic applications. Notably, a four-terminal tandem solar cell configuration comprising CaZrS3 and CaSnS3 achieves a peak conversion efficiency of 55.5% at an absorber thickness of 500 nm, surpassing the traditional Shockley-Queisser limit. These results underscore the promising capabilities of CaBS3 perovskites in advancing renewable energy technologies, paving the way for innovative designs in solar energy solutions.This investigation lends empirical credence to the optimization of tandem cell designs, thus catalyzing advancements in next-generation photovoltaic technologies.