Visible Light Region Research Articles

Mechanical and electrical properties of α-MoO3 belts under strain for flexible electronics applications

This study investigated a straightforward and cost-effective method for synthesizing α-MoO3 belts and evaluated their potential as substrates for flexible electronic devices. Transparent α-MoO3 belts, featuring millimeter-scale side lengths and micrometer-scale thicknesses, were produced through a one-step sintering process using metallic molybdenum powder. When affixed to stretchable substrates, the α-MoO3 belts demonstrated robust mechanical stability under continuous and sustained tensile strain in the longitudinal direction. The belts exhibited a transmittance exceeding 68 % in the visible and near-infrared light regions. The current between gold dots on belts fixed to a stretchable polydimethylsiloxane substrate increased with the application of tensile strain. Furthermore, a CoFe2O4 thin film deposited at elevated temperature onto an α-MoO3 belt exhibited significant magnetic anisotropy. These findings introduce a novel and efficient approach for fabricating highly crystalline thin films on stretchable and bendable substrates using α-MoO3 belts.

Growth and characterization of Sb2(SxSe1-x)3 thin films prepared by chemical-molecular beam deposition for solar cell applications

Antimony sulfide selenide, Sb2(SxSe1-x)3 (x = 0–1), is a tunable bandgap compound that combines the advantages of antimony sulfide (Sb2S3) and antimony selenide (Sb2Se3). This material shows great potential as a light-absorbing material for low-cost, low-toxicity, and highly stable thin-film solar cells. In this study, Sb2(SxSe1-x)3 thin films were deposited by chemical-molecular beam deposition on soda-lime glass substrates using antimony (Sb), selenium (Se), and sulfur (S) precursors at a substrate temperature of 420 °C. By independently controlling the source temperatures of Sb, Se, and S, Sb2(SxSe1-x)3 thin films with varying component ratios were obtained. Scanning electron microscopy revealed significant changes in the surface morphology of the films depending on the elemental ratio of [S]/([S]+[Se]). Crystallites shaped like cylindrical microrods with d = 0.5–2 µm diameter and l = 3–5 µm length were grown at a certain angle on the substrate. X-ray diffraction patterns showed peaks corresponding to the orthorhombic structures of Sb2Se3, Sb2S3 and their ternary compounds Sb2(SxSe1-x)3. The optical characterization revealed a high absorption coefficient of 105 cm−1 in the visible and near-infrared light regions. The band gap of the compounds changed almost linearly from 1.2 eV to 1.36 eV with a change in the ratio of elements [S]/([S]+[Se]) from 0.03 to 0.08.

Optical Study on Co-Sensitization of Betanin Dye with Cadmium Sulfide to Fabricate Dye Sensitized Solar Cell

Natural dyes are low-cost, eco-friendly, readily available and have optical characteristics which render them useful in energy research. The titanium tetra isopropoxide precursor can be employed using sol-gel synthesis to get titanium dioxide nanoparticles (TiO2 NPs). The FESEM analysis confirmed the deposition of TiO2 NPs on Indium Tin Oxide (ITO) substrate, which is necessary for the photo-conversion mechanism to produce electricity. One of the natural dyes that is extracted from red beets is known as betanin dye (Bd). Due to their aligned energy levels, Bd and cadmium sulfide (CdS) are used together to provide effective optical characteristics, making them suitable as dye sensitizers. The presence of Cd-S, C-N and hydroxyl groups assigned to 500, 1633, and 3300 cm-1 respectively, was demonstrated by the FTIR analysis. The energy gap of 2.16, 2.13 and 2.2 eV for Bd, CdS and Bd-CdS composite was estimated using Tauc's plot and UV-visible spectra demonstrated maximum absorbance at 485, 510 and 528 nm, respectively. The Bd absorbs broad light in visible region due to the addition of CdS. The major charge-transport phenomenon in dye-sensitized solar cells (DSSC) involves an increase in photo-current density, due to its luminous nature. However, the recombination of charge carriers prevents the overall performance of the DSSCs. The power conversion efficiency of the DSSC constructed from Bd dye and Bd-CdS composite was 0.234% and 0.367%, respectively. This optical investigation suggests co-sensitization as a sure-fire method to improve the efficiency of DSSCs extracted from natural dyes, making them reliable for future indoor applications.

Biosynthesis of Iron Oxide Nanoparticles by Fungi Beauveria Bassiania and Study of their Structural and Optical Properties

Iron oxide nanoparticles were synthesized using a biological approach using the Beauveria bassiana fungus. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), scanning analysis (SEM), and atomic energy microscope (AFM). The iron nanoparticles in an average grain size of ~ 39 nm. The topography and features of the surface show that there are ripples distributed regularly and homogeneously on the surface and that the deposited film is regular. The optical properties of iron oxide were studied using UV/Vis spectroscopy, and it was found that the absorbance gradually decreases as we approach the visible light region, starting from its peak at short wavelengths, where the surface plasmon resonance was recorded, which showed the absorbance at the UV wavelength at (282 nm), and the absorbance is at its maximum at high energies (short wavelengths), then decreases with increasing wavelength to reach its lowest value in the visible region of the spectrum, and for this reason the absorbance decreases with increasing wavelength, where the energy gap value is (2.5 electron volts). The FTIR spectrum showed functional groups have been recorded in a range These results confirm the presence of the fungal extract belonging to the fungus Beauveria bassiana. The vibrations in the phenolic compounds are responsible for the interaction process with the salts of the basic materials used in the preparation

First principles calculations of double perovskite RbX2Y3O10 (X = Ca, Ba: Y[dbnd]Cd, Ta) materials for photocatalytic applications

Production of oxygen and hydrogen energy through suited photocatalysts by water splitting is the main issue in the modern age. In this regard, the double perovskite Dion-Jacobson materials RbX2Y3O10 (X = Ca, Ba: YCd, Ta) for photocatalytic activity are investigated by using the CASTEP package. The plane-wave (PW) pseudo-potential in the context of the generalized gradient approximation (GGA)-Perdew Burke Ernzerhof (PBE) and local density approximation (LDA) exchange-correlation functional technique is used to investigate the compounds. According to the results, compounds have a tetragonal (a = b≠c) structure with space group 123 (p4/mmm). Compounds Mullikan bond populations were estimated in order to comprehend the bonding characteristics that found a mixed ionic and covalent bonding. According to electronic characteristics, RbBa2Ta3O10, RbBa2Cd3O10, and RbCa2Cd3O10 have semiconductor behavior with indirect bandgap of 2.11 eV, 2.27 eV, and 1.51 eV, respectively, and respond under visible region light. DOS and PDOS are studied to inspect the distinct atom's contribution to electronic band structure. The compounds are mechanically brittle (1.55, 1.39), ductile (1.97), and stable in their natural form, according to elastic constant values. The optical characteristics simulation indicates that compounds have the potential to decompose or oxidize organic contaminants. According to the results, these compounds are suitable for the water-splitting photocatalytic process to produce oxygen and hydrogen.

Investigation of methylene blue dye degradation using green synthesized mesoporous silver-titanium

In this study, we synthesized mesoporous silver-titanium (Ag/TiO2) through green synthesis approach using mangosteen pericarp extract, which subsequently can act as both adsorbent and photocatalyst materials. Additionally, we investigated and compared the degradation of methylene blue (MB) using mesoporous Ag/TiO2 under dark conditions, visible light irradiation, and both dark-light conditions to analyze the adsorption-photocatalysis activity. The achieved mesoporous structure in this study offers distinct advantages as an adsorbent. Moreover, the addition of silver (Ag) to titanium dioxide (TiO2) shows promise in enhancing photocatalytic activity in MB degradation, which enhances photocatalytic activity in the visible light region due to its localized surface plasmon resonance (LSPR), which excites more electrons, resulting in increased MB degradation. The highest degradation percentage of 97.08 % was obtained using a dark-light degradation mechanism, demonstrating that the synthesized mesoporous Ag/TiO2 has potential as an effective integrated adsorbent-photocatalyst material for MB dye degradation.

Two-dimensional tetragonal carbon nitride semiconductors with fascinating electronic/optical properties and low thermal conductivity

Abstract Exploring two-dimensional (2D) tetragonal carbon nitride materials is significant for unlocking new physical properties beyond those offered by traditional hexagonal lattices. In this work, we propose three theoretically stable 2D carbon nitride monolayers with tetragonal lattices, namely T-C3N, P-C3N, and PH-C5N4. Electronic structure calculations indicate that all three monolayers exhibit semiconducting characteristics, with T-C3N showing interesting flat band features. Additionally, these three carbon nitrides exhibit anisotropic and high carrier mobilities and excellent light absorption capabilities in the visible-light and near-infrared regions. Meanwhile, the calculated thermal conductivity (κp) of PH-C5N4 is 63.9 Wm−1K−1 at room temperature, significantly outperforming T-C3N (12.2 Wm−1K−1) and P-C3N (18.9 Wm−1K−1). Phonon scattering rates and Grüneisen parameters confirm the origin for the relatively high κp in PH-C5N4. Our study proposes three tetragonal carbon nitride structures with novel physical properties, which lays a theoretical foundation for the multifunctional applications of 2D carbon nitride materials.

Effect of structural evolution and orientation behavior on optical properties of iodine-dyed PVA film during uniaxial stretching

In the process of preparing polarizing film, based on the research on the influence of the initial condensed structure of Poly (vinyl alcohol) (PVA) film on the dyeing and stretching process, the connection between the structure and performance of polarizing film is established, which is more conducive to understanding the post-processing process of solution casting molding of optical grade PVA film and the optimization of subsequent dyeing and stretching process. In this paper, PVA film with an appropriate swelling degree were selected for dyeing treatment, and the evolution of the condensed structure during stretching was studied in detail. The work also examined the formation and orientation of PVA-iodine complexes and the feedback effect of complex formation on the structural evolution of the film, with the goal of establishing the relationship between stretching ratio, structure, and performance of the polarizing film. The results show that the dyeing process inhibits the recrystallization of the PVA film during uniaxial stretching. However, the PVA-iodine complexes formed act as "anchors" to stabilize the oriented microfiber network, reducing the critical strains (εw and εs) required for the PVA film to enter the strain-hardening zone. Furthermore, as strain increases, the content of polyiodide ions and PVA-iodine complexes in the dyed PVA film also increases, especially making the formation of long iodide chains (I5−) and PVA-I5− complex more sensitive. Additionally, with increasing strain, both the transmittance and degree of polarization of the dyed PVA film improve, reaching optimal values in the strong strain-hardening zone (>εs). This indicates that εs is the minimum critical strain required to ensure optimal polarization performance of the film in the visible light region.

The CoNb2O6 pigments for brilliant-blue ceramic decoration at high temperatures over 1273 K

To date, brilliant-blue pigments that can maintain outstanding stability in a corrosive environment over 1273 K are still very desirable in the ceramic industry. We systematically investigated the structural, optical, colorimetric and thermal properties of a novel type of CoNb2O6 pigments, which have the 6-fold coordinated Co2+ as chromophores and high-valent Nb5+ as the mainstay factor for structural stabilization. Effective coloring contribution from different visible-light regions, the coloration mechanism and thermal stability of the pigments applied in glaze at 1273–1473 K are revealed for the first time. The Co2+ cation at the distorted [CoO6] octahedra generates the brilliant blue hue, which can maintain the absolute blueness values, b*, at 30–44 even after glaze calcination at 1273–1423 K. The superb thermal performance in a harsh environment of the CoNb2O6 pigments significantly outperforms the classic CoAl2O4 blue, thereby exhibiting attractive prospects for high-end blue-sky–hued decoration for ceramics.

Comparative characterizations of plant and mineral dye as potential photosensitizer in Dye-Sensitized Solar Cell

The advent of dye-sensitized solar cells (DSSC) has expansively seen more studies as an alternative to silicon-based and thin-film solar cells due to their simple structure and relatively low production cost. In dye-sensitized solar cells, the dye is one of the major components for high power conversion efficiencies. The extracted dyes were characterized by powder x-ray diffraction, x-ray fluorescence, Scanning electron microscopy, UV-visible spectroscopy, and Gas Chromatography-Mass spectrometry analysis. The structure of the mineral dye contains constituents that enhance better absorption of solar radiation for use in a Dye-Sensitized Solar Cell (DSSC). The calcium and iron content of the mineral dye studied as revealed by the mineralogical analysis done using the powder x-ray diffraction (XRD) and the x-ray fluorescence (XRF) suggest this. These metals serve as bounding complexes to other organic components in the dye, like in the case of Ruthenium complexes dye for efficient absorption of solar radiation, especially in the visible light region. The functional groups present in the dye also confirm what favors good absorption of solar radiation for DSSC application. The Organic chemical compositions present in the mineral dye which were obtained by the Gas Chromatography-Mass spectrometry analysis also confirm the functional groups of carbonyl, Amine, and hydroxyl revealed by FTIR, which were responsible for solar radiation absorption. There are strong absorption narrow bands in the visible region with peaks at around 424 nm (2.903 a.u) and 486 nm (2.973 a.u). Optical band gaps of 1.66 eV and 2.27 eV for the mineral dye and plant dye respectively, were obtained. The properties of the dyes studied give potential substitutes to the relatively expensive ruthenium-based dyes for use in DSSC fabrication.

Insight into the Structural and Performance Correlation of Photocatalytic TiO2/Cu Composite Films Prepared by Magnetron Sputtering Method

Photocatalysis technology, as an efficient and safe environmentally friendly purification technique, has garnered significant attention and interest. Traditional TiO2 photocatalytic materials still face limitations in practical applications, hindering their widespread adoption. The research prepared TiO2/Cu films with different Cu contents using a magnetron sputtering multi-target co-deposition technique. The incorporation of Cu significantly enhances the antibacterial properties and visible light response of the films. The effects of different Cu contents on the microstructure, surface morphology, wettability, antibacterial properties, and visible light response of the films were investigated using an X-ray diffractometer, X-ray photoelectron spectrometer, field emission scanning electron microscope, confocal laser scanning microscope, Ultraviolet–visible spectrophotometer, and contact angle goniometer. The results showed that the prepared TiO2/Cu films were mainly composed of the rutile TiO2 phase and face-center cubic Cu phase. The introduction of Cu affected the crystal orientation of TiO2 and refined the grain size of the films. With the increase in Cu content, the surface roughness of the films first decreased and then increased. The water contact angle of the films first increased and then decreased, and the film exhibited optimal hydrophobicity when the Cu target power was 10 W. The TiO2/Cu films showed good antibacterial properties against Escherichia coli and Staphylococcus aureus. The introduction of Cu shifted the absorption edge of the films to the red region, significantly narrowed the band gap width to 2.5 eV, and broadened the light response range of the films to the visible light region.

The stability, electronic and optical properties of nonmetal doped g-GaN: A first-principles calculation

Doping is an effective strategy to modulate the electronic performance of materials by forming new chemical bonds and relaxing the neighboring bonds, which may change catalytic performance of materials. Herein, we demonstrate the effects of a series of nonmetal (NM) dopants on the electronic properties and photocatalytic activity of g-GaN monolayer using first-principle calculations. NM dopants prefer to substitute N atom under Ga-rich condition. C, O and F doped specimens are highly stable under both Ga-rich and N-rich conditions. NM dopants induce the generation of impurity levels, contributing to reduce the electronic transition energies. S, Se and Te doped specimens increase by about 11, 8 and 4 times for absorption intensity in the region of visible light, respectively. Remarkably, S, Cl, Se, Br, Te and I dopants can effectively decrease the recombination rate of photogenerated electrons and holes of the g-GaN in photocatalytic reaction. H, B, C Si, P and As doped system can induce more active sites. Remarkably, halogen dopants could increase the both redox and reduction ability of g-GaN monolayer. Thus, NM dopants can effectively tune redox potential of g-GaN monolayer and improve its photocatalytic performance.

First-principles study of the electronic, optical adsorption, and photocatalytic water-splitting properties of a strain-tuned SiC/WS2 heterojunction

Heterojunction is widely acknowledged as a potent strategy as an effective means for achieving quality electronic, optical adsorption, and photocatalytic water-splitting properties. Strain also can regulate these properties effectively. In this study, we have fabricated and studied a heterojunction comprised SiC and WS2. Utilizing a first-principles method, we systematically investigated the SiC/WS2 heterojunction's structure, stability, electronic, and optical properties, as well as its photocatalytic water splitting characteristics under strain engineering. Our calculations reveal that the SiC/WS2 heterojunction is a type-II heterostructure with two stable structures, which exhibits a direct bandgap and well performance in the visible light region, facilitating efficient separation of photogenerated electron-hole pairs. We have explored and discussed the impacts of biaxial strain on the various properties. The bandgaps of System-A and B are 1.778 eV and 1.820 eV, respectively, without strain. Under strain from −6% to 10%, they initially rise, peak at 1.858 eV and 1.899 eV respectively at −2% strain, then decline. Without strain, effective mass mh/me for both structures are 1.642 and 1.673. Under positive strain, they increase, decrease, then increase again, peaking at 6% with 2.116 and 2.260. At −2% strain, values drop to 0.901 and 0.910 for A and B, respectively. Our calculations also demonstrate that the SiC/WS2 heterostructure qualifies as a promising photocatalytic material, fulfilling the criteria for water splitting under strain conditions of −4%, −2%, and 0%. And the heterojunction with System-B under −4% strain has the optimal performance in photocatalytic water splitting. At a strain of −4%, System-B achieves the maximum η′STH of 16.91%. In conclusion, our study not only offers fundamental insights into the utilization of SiC/WS2 heterojunctions for photocatalytic water splitting, but also provides the foundational design principles of heterojunctions.

Preparation and characterization of ZnS/metal/ZnS transparent conductive multilayer films with different metal layers

ZnS/metal/ZnS transparent conductive multilayer films were deposited on quartz glass by pulsed laser deposition at room temperature with Au, Ag and Cu as the metal layers, and annealed in air at 100, 200 and 300℃ for 1 h. XRD patterns show that β -ZnS(111) diffraction peak of ZnS/Au/ZnS is stronger and sharper than the other two samples, indicating that its crystalline quality is the best. SEM images show the good structural homogeneity of the samples with smooth and compact film surfaces. When the annealing temperature increases from 100 to 300℃, the sheet resistance decreases first and then increases, while the carrier concentration changes in the opposite trend. The maximum transmittance (~85%) for ZnS/Au/ZnS in the visible light region is observed when the sample is annealed at 200℃. The figure of merit is calculated, and the best sample suitable for transparent conductive electrode is determined.

Self‐Powered Cs3Bi2I9/ZnO Heterojunction Photodetector with Dual‐Band Photoresponse

AbstractCs3Bi2I9/ZnO heterostructures are constructed by the growth of Cs3Bi2I9 layer onto the spin‐coated ZnO films by a modified antisolvent recrystallization method, a series of Cs3Bi2I9/ZnO heterojunction photodetectors (PDs) with varied growth times of Cs3Bi2I9 layer are fabricated. The construction of Cs3Bi2I9/ZnO heterojunction contributes to their improved photoelectric performance compared to ZnO‐based PD, and the Cs3Bi2I9 layer thickness plays an important role in tuning the photoelectric performance of these PDs. At 405 nm and 0 V bias, the optimized 6‐Cs3Bi2I9/ZnO PD generates a high photocurrent of −3.03 µA, a medium on/off ratio of 144.3, and a short response time of 16.4 ms/16.8 ms. It also exhibits superior dual‐band self‐powered photoresponse with two responsivity and detectivity peaks at 380 nm in the UV region and at 430 nm in the visible light region. At 380 nm, this PD presents the highest responsivity of 33.2 mA W−1 and detectivity of 1.07 × 1010 Jones. It is believed that the optimized growth of the Cs3Bi2I9 layer generates a depletion layer with suitable thickness near the interface, and the as‐promoted charge‐carrier separation and transport result in improved self‐powered properties. The rational construction of perovskite‐based heterojunction has proved as an efficient way to achieve self‐powered photodetection.

Optimizing junction interface integrity between 3D/2D defect pyrochlore Bi1.8Fe0.2WO6 and g-C3N4 nanostructures: A novel multifunctional nanocomposite for enhanced photocatalytic and photo-electrocatalytic water splitting and water remediation applications

In this work, a simplistic composite fabrication of defect pyrochlore Bi1.8Fe0.2WO6 (BFWO) and g-C3N4 (g-CN) was carried out to augment the photocatalytic degradation kinetics and Hydrogen (H2) evolution rate. The structural confirmation through XRD and FTIR confirmed the successful formation of pristine g-C3N4, BFWO NPs, and their composites. FESEM micrographs revealed multilayered sheet-like formation for C3N4 whereas irregular cuboid-shaped structure for BFWO NPs. In the composite formation, the sheets tended to appear wrapped around the BFWO NPs. The UV-DRS absorbance spectra exhibited a highlighted increase in the absorbance region towards the visible light region following a decrease in the band gap. The photoluminescence lifetime studies revealed an enhanced lifetime of excitons to 6.21 ns for 50:50 (g-C3N4: BFWO) composite formation, whereas pristine g-CN displayed an average lifetime of about 4.79 ns. The degradation efficacy in the removal of RhB and MB from water revealed up to 100% and 95.5% removal rates in under 90 mins and 180 mins respectively using the 50:50 composite formation. Similarly, the H2 evolution rate was significantly improved and exhibited up to 370 μmol/h/g. The photo-electrochemical studies revealed a sharp charge separation of excitons for 50:50 (g-C3N4: BFWO) with a maximum photocurrent density of -0.54 μA/cm2 @ 0 V which is 3.6 times and 13.5 times higher than bare g-CN and BFWO. 1.33 V vs. RHE for OER kinetics and -0.09 V vs RHE for HER kinetics were the minimal onset potential exhibited for equal ratios of BFWO and g-CN. Coupled with the heightened charge separation, reduced recombination rate, and optimal band edge positions, the photocatalytic efficiency in the degradation of RhB and MB and water-splitting reactions were improved.

Decarboxylative Alkylation of Carboxylic Acids with Easily Oxidizable Functional Groups Catalyzed by an Imidazole-Coordinated Fe3 Cluster under Visible Light Irradiation.

Decarboxylative alkylation of carboxylic acids with easily oxidizable functional groups such as phenol and indole functionalities was achieved using a catalytic amount of basic iron(III) acetate, Fe(OAc)2(OH), in the presence of benzimidazole under 427 nm LED irradiation. Kinetic analyses of this catalytic reaction revealed that the reaction rate is first-order in alkenes and is linearly correlated with the light intensity; the faster reaction rate for the benzimidazole-ligated species was consistent with the increased absorbance in the visible light region. Wide functional group tolerance for the easily oxidizable groups is ascribed to the weak oxidation ability of the in situ-generated oxo-bridged iron clusters compared with other iron(III) species.

Synergistic Approach of TiO2@MnZnO3 Heterostructure for Efficient Photoelectrochemical Water Splitting

The superior kinetics of charge carriers and greater visible light absorption are important factors for enhancing photoelectrochemical performance. Herein, the core–shell heterostructure has been developed by encapsulating single-phase MnZnO3 over TiO2 nanotubes by aerosol-assisted chemical vapor deposition approach. The fabricated photoanodes have been characterized by employing various techniques including X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy, and photoluminescence. Moreover, the mechanism for electron/hole transfer has been focused by a brief electrochemical investigation. The bilayer 1D/2D TiO2@MnZnO3 photoanode exhibited higher current density (2 mA cm−2) as compared to pristine TiO2-nanotubes (0.174 mA cm−2) at 1.52 V vs RHE. The superior photoactivity of heterostructure is attributed to the rapid transfer of photogenerated charge carriers via the Type-II mechanism. Furthermore, the reduced band gap (2.05 eV) accounts for good absorption in the visible region of light, while the interfacial electric field allowed the improved charge separation. The synergistic strategy in the present work demonstrates the promising significance of a heterojunction interface to optimize photovoltaic devices.

Research on optical properties of Eu3+ doped bismuth silicate crystals based on first principles

This paper is based on the first principles of density functional theory and uses the virtual crystal approximation method to calculate and analyze the optical properties of differently proportioned Eu3+-doped Bismuth silicate (Bi4Si3O12, or BSO). The results show that minor Eu3+ doping (1/12–1/3) improves the polarization ability of BSO and reduces energy loss. Additionally, doping an appropriate amount of Eu3+ (1/12–1/3) can improve light absorption and transmission of BSO to some extent. That is to say, Eu3+ doping improves the response of BSO to infrared light, and the absorption capacity in the ultraviolet and visible light regions is also enhanced. The theoretical research in this paper elucidates the changes in the optical properties of BSO after doping with Eu3+, providing a theoretical basis for expanding its application as a scintillation crystal in high-energy physics experiments, nuclear medicine, and other fields.

Strain tunable excitonic optical properties in monolayer Ga2O3

Abstract Two-dimensional (2D) Ga2O3 has been confirmed to be a stable structure with five atomic layer thickness configuration. In this work, we study the quasi-particle electronic band structures and then access the excitonic optical properties through solving the Bethe–Salpeter equation (BSE). The results reveal that the exciton dominates the optical absorption in the visible light region with the binding energy as large as ∼ 1.0 eV, which is highly stable at room temperature. Importantly, both the dominant absorption P1 and P2 peaks are optically bright without dark exciton between them, and thus is favorable for luminescence process. The calculated radiative lifetime of the lowest-energy exciton is 2.0×10−11 s at 0 K. Furthermore, the radiative lifetime under +4% tensile strain is one order of magnitude shorter than that of the strain-free case, while it is less insensitive under the compressive strain. Our findings set the stage for future theoretical and experimental investigation on monolayer Ga2O3.