Direct Band Gap Values Research Articles

Low temperature sol-gel synthesis of copper zinc ferrite for hydrogen catalytic hydrolysis of sodium borohydride

The spinal ferrites are regarded as promising for renewable energy application like hydrogen production from sodium borohydride (NaBH4) since they have superior catalytic activity. The current work considers the preparation of Cu1-xZnxFe2O4 (x = 0.0, 0.2, 0.4, 0.6 and 0.8) nanoparticles via the low temperature sol-gel method. The cubic crystal structure of nanoparticles was identified by XRD spectra analysis. The average crystal size was provided concerning the full width at half maximum to be 10.0 nm according to Scherer formula. FTIR spectra of synthesized ferrite nanoparticles showed the vibrational bands of Cu1-xZnxFe2O4. The images showed a cross-linked porous surface morphology. The TEM images of the CuFe2O4 and Cu0.6Zn0.4Fe2O4 samples showed spherical nanoparticles with an average size of 10 nm. The surface area BET at 0.0, 0.2, 0.4, 0.6 and 0.8 content of zinc were 95, 66, 46, 49 and 41 m2/g. The values of direct band gaps for nanocrystalline Cu1-xZnxFe2O3 were 52.25, 2.0, 2.16, 1.9 and 2.11 eV at x = 0.0, 0.2, 0.4, 0.6, and 0.8. The hydrogen catalytic effect of Cu1-xZnxFe2O4 nanoparticles is accelerated, especially the sample CuFe2O4. The nanoparticles show high generation rates but the sample CuFe2O4 is the highest catalytic material (1810 mL/gmin).

Thickness dependent physical and optical properties of SILAR deposited titania films

Uniform and crystalline titanium dioxide (TiO2) thin films were obtained using Successive Ionic Layer Adsorption and Reaction (SILAR) technique. Films having varied thicknesses over a range from 700 nm to 1000 nm are deposited on glass substrate. Further TiO2 films were annealed at 673 K for 2 h. X-ray diffraction measurements of both annealed and as deposited films were done to analyze the effect of temperature. Crystallite size and micro strain of the TiO2 films were calculated to study their trend with different thicknesses of the film. Morphological and compositional characteristics are studied by Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Analysis (EDX) respectively. Images showed formation of uniform film without discontinuities on the base substrate. Optical constants of the films are figured out using UV–vis spectrophotometry. Absorbance spectra showed that as the thickness of the films increased absorbance of the films also increased. Direct and indirect bandgap values of TiO2 films was found using Tauc’s plot.

A Mesoporous CuO/CuSe Heterojunction Nanocomposite with Applications in Visible‐Light Photocatalysis and as an Electrochemical Phenol Sensor

AbstractA new study has successfully fabricated a CuO/CuSe heterojunction nanocomposite using an eco‐friendly green method, which can be used as a potential photocatalyst and for phenol sensing applications. The nanocomposite has been characterized using various microscopic and spectroscopic methods, and it was found to have a direct band gap value of 2.14 eV, which indicates it can exploit visible light for its properties. The nanocomposite was tested for photocatalytic degradation of two dyes, Rhodamine B (RhB) and Methyl Orange (MO), and achieved removal efficiencies of 99.32 % and 88.20 %, respectively, using hydrogen peroxide. The nanocomposite was also found to have potentiality for practical use in phenol sensing, detecting concentrations of 0.2–1.4 μM phenol in solution and demonstrating 96–100 % phenol recovery in real water samples.

Temperature cycling effect on structural, optical and electrical properties of nanostructured sodium titanates

Sodium titanates represent a promising alternative for the construction of anodes for sodium-ion batteries. To study the electrical response of nanostructured sodium titanate samples under plausible temperature conditions, we evaluate the electrical impedance in the range of temperatures from −30 ∘C to 50 ∘C, and the effect of consecutive temperature cycling. Strong changes in electrical properties are observed during the first temperature cycle, followed by a stabilization in the consecutive cycles. This behavior is reversible when the sample is exposed to external conditions and room temperature for less than an hour. Probably a structural and surface water removal and a surface water reabsorption occur, affecting the charge carriers and with it the impedance. Structurally, no differences are detected before and after the cycles, nor when evaluating only the vacuum process. However, when the optical properties are evaluated we find non-reversible changes after the temperature cycles. The optical behavior after the temperature cycling becomes uniform, the same type of electronic defects become predominant and similar direct and indirect band gap values are obtained, regardless of the starting synthesis condition. These results have significant implications for potential technological applications of these materials.

Structural and optical behaviours of methyl acrylate-vinyl acetate composite thin films synthesized under dynamic low-pressure plasma

Low-pressure (33.33 Pa) plasma polymerized methyl acrylate and vinyl acetate composite thin films with various monomer compositions were deposited onto glass substrates. Under the same plasma conditions, the homopolymer thin films were also prepared. The thickness of the composite films was observed to vary between 117 and 213 nm depending on the monomer ratio. The composite films exhibit a smooth, pinhole-free, and immaculate surface morphology, surpassing that of the homopolymers. The energy dispersive x-ray study shows that the films contain mainly carbon and oxygen with 26.09–37.20 at% and 35.03 − 40.10 at%, respectively. The composite films contain more carbon contents which enhance the film stability. The appearance of some broad absorption bands in the Fourier transform infrared spectroscopy indicates structural changes in the PP films caused by the restructuring or dilapidation of monomer molecules while forming the polymer. The UV–visible spectra analysis reveal that the composite films exhibited a tunable optical band gap by adjusting the monomer ratio. The decrease of methyl acrylate monomer reduces the direct and indirect optical band-gap values of composite films from 3.15 to 3.00 eV and 2.35 to 1.74 eV, respectively. While Urbach energy values increases from 0.33 eV to 0.90 eV. All the films showed good transmittance properties (86 − 96%) in the visible range wavelength (550 − 800 nm). Other optical parameters are also found better in composite films which indicates the aptness of the composite films in various optoelectronic or electronic applications.

Green Synthesized TiO2-SnO2 Nanocomposite for the Photocatalytic Degradation of Methylene Blue Dye

Abstract: TiO2-SnO2 nanocomposite was prepared by green synthesis method with the help of the Allium sativum extract obtained from garlic cloves. The green synthesized TiO2-SnO2 nanocomposite was characterized by XRD, SEM, EDS, Raman, ATR-FTIR, and UV-Visible spectroscopy. The XRD pattern reveals the polycrystalline nature of the synthesized nanocomposite and indicates the simultaneous presence of anatase and rutile phases of TiO2, along with SnO2. The calculated average crystallite size is 11.79 nm. The SEM images give the concept of surface morphologies of the synthesized nanocomposite. EDS spectrum detects the presence of Ti, Sn, and O in the synthesized nanocomposite material. The Raman spectrum confirms the chemical compositions. ATR-FTIR spectrum shows the presence of organic components of garlic as functional groups in the synthesized nanocomposite. The Tauc plot obtained from the UV-Visible spectral data displays the direct and indirect band gap values of 3.97 and 3.25 eV, respectively. Moreover, the present study investigates the effect of the synthesized nanocomposite’s concentration on the photocatalytic degradation of methylene blue (MB) dye. The aqueous suspension of TiO2-SnO2 nanocomposite photocatalyst with a concentration of 1.5 mg/mL exhibits maximum photocatalytic activity. Keywords: Green synthesis, TiO2-SnO2 nanocomposite, Allium sativum extract, Photocatalytic activity, Methylene blue.

Opto-structural properties and photocatalytic activities of CuO NPs synthesized by modified sol-gel and Co-precipitation methods: A comparative study

The study presents a comprehensive investigation into the synthesis of CuO nanoparticles (NPs) through two distinct chemical processing methods, namely modified sol-gel and co-precipitation, and delves into the intricate details of the process optimization and explores the opto-structural properties of the synthesized NPs. The crystal structure of the NPs produced following both the routes was monoclinic with high crystallinity as revealed from their X-ray diffraction (XRD) pattern analysis. However, the co-precipitation route yields slightly larger crystallite sizes and higher crystallinity for lower annealing temperatures. Field emission scanning electron microscope (FE-SEM) revealed that the NPs obtained from sol-gel route have fused irregular-shaped cluster structure, whereas NPs produced via co-precipitation route exhibit a well-controlled spherical morphology. The study further characterizes the optical properties of the NPs through UV–Vis spectroscopy and demonstrates that both direct and indirect band gap values are higher for NPs produced through the sol-gel method. Moreover, NPs synthesized through co-precipitation exhibit superior photocatalytic activity compared to those produced through sol-gel, attributed to their unique morphological attributes. Photocatalytic properties were investigated from the degradation of rhodamine B under ultra-violet (UV) irradiation.

Rb2PtX6 (X=I, Br, Cl) vacancy-ordered double perovskites: Effect of halogens on the structural, electronic, and optical properties

The structural, electronic, and optical characteristics of Rb2PtX6 (X = I, Br, Cl) so-called vacancy-ordered double perovskites are explored via first-principles calculation using PBE and HSE06 hybrid functions. The lattice constants as well as the optimized volume both exhibit an upward trend with chancing X-atoms. The calculated band structures for Rb2PtCl6, Rb2PtBr6, and Rb2PtI6 demonstrate that Rb2PtX6 perovskites exhibit semiconductor qualities and direct bandgap values are 3.24 eV, 2.24 eV, and 1.20 eV, respectively. Optical properties indicate that Rb2PtX6 compounds have strong absorption in visible and ultraviolet regions. The absorption spectra red-shift with an increasing number of X-site atoms. Our results suggest that Rb2PtX6 (X = I, Br, Cl) are suitable materials for applications as light absorption layers in solar cells.

Influence of Deposition Parameters for Cu2O and CuO Thin Films by Electrodeposition Technique: A Short Review

The transition metal oxide-based nanomaterial attracted researchers for its various applications due to its interesting physical, chemical, and optical properties. Copper oxide thin films with different oxidation states were prepared on various transparent, nontransparent nature conducting substrates from the acidic and alkaline medium by electrodeposition technique. The deposition parameters such as potential, bath temperature, solution pH, and deposition time determine the physical, chemical, and optical properties. The complexing agents such as sodium thiosulfate, lactic acid, citric acid, and triethanolamine determine the stability of cuprous and cupric ions in the deposited films. Optical properties reported that the deposited films have direct band gap value 1.3 and 3.7 eV represents the absorbance of the deposited films in the visible region of solar spectrum. The absorbance of light in visible region, good electrical conductivity, and various nanostructure morphologies with the environment-friendly constituents are the distinctive properties of copper metal oxides.

Cu2ZnSnS4 films properties deposited by spray pyrolysis, subjected to a combined novel thermal treatment: CSS sulfurization and RTA post-treatment

CZTS films were obtained by spray pyrolysis, a low-cost technique implemented on an industrial scale. Sulfurization processes generally enhance CZTS properties for its use in solar cells; however, these require high temperatures and long times. In this work, CZTS films properties were studied after being subjected to a combined novel thermal treatment which involved two stages. Sulfur incorporation using close space sublimation technique (CSS) at a temperature (TCSS) in the 350–500 °C range for 60 s, and after a rapid thermal annealing post-treatment (RTA) at TRTA = 500 °C for 10 s, with a heating ramp of 5 °C/s under argon atmosphere. Morphological, structural, chemical composition, optical and electrical properties were studied for CZTS films subjected to CSS as CSS+RTA treatments for all TCSS values. From the results, efficient sulfur incorporation by CSS was obtained without substantial sulfur concentration loss after RTA treatment, associated with the short treatment time. In addition, significant enhancement of crystalline quality and electrical resistivity diminished of the films is obtained after the CSS+RTA process for all TCSS. CZTS films with the best properties are those obtained at TCSS of 400 °C, having Cu/(Zn+Sn) = 0.79 and Zn/Sn = 1.3 ratios, a direct bandgap value of 1.5 eV, and resistivity of 4 Ω-cm. These films can be candidates for their characteristics as an absorbent layer in solar cells.

Carmoisine azo dye-modified Al/p-Si junction

This study investigates the impact of a Carmoisine azo dye layer on electronic transport at the p-silicon/Al interface. The morphology of the Carmoisine azo layer is characterized using atomic force microscopy (AFM). Various spectroscopic measurements, including nuclear magnetic resonance (NMR), ultraviolet–visible (UV–Vis), and Fourier transform infrared (FTIR) spectroscopy, are employed to analyze the Carmoisine dye molecule. The direct and indirect band gap values of the Carmoisine dye molecule, prepared in methanol solvent, are determined to be Eg,1 = 2.15 eV and 2.06 eV (D band) and Eg,2 = 3.54 eV and 3.35 eV (C band), respectively. Results indicate that the Carmoisine film on a glass slide consists of non-homogeneous microstructures, with a surface roughness of 16.76 nm. A spin coater is used to form an Al/Carmoisine/p-Si device, which is a cost-effective and readily scalable approach for creating semiconductor films. The basic contact parameters of the Al/p-Si and Al/Carmoisine/p-Si contacts are measured using current-voltage (IV) and capacitance-voltage (CV) techniques. The Al/Carmoisine/p-Si device exhibits good rectifying behaviour, with an ideality factor value of 1.547, indicating that the Carmoisine azo dye used as the interface material enhances the junction's performance and reduces the ideality factor. Barrier height (BH) parameters are calculated to be 0.770 eV, 0.733 eV, and 0.799 eV using the lnI-V, Cheung, and Norde techniques, respectively. The interfacial dipole created by passivation of the film causes the Carmoisine interlayer to raise the BH, resulting in an improved interface region for Al/p-Si structures. The extracted interfacial level concentration (Nss) of the Al/Carmoisine/p-Si junction is lower than that of the Al/p-Si contact, indicating that the Carmoisine dye molecule reduces the Nss value. Furthermore, the reverse bias 1/C2-V characteristic is employed to analyze the barrier height values and compare the findings to those from the IV method. The results show that the thin Carmoisine azo dye layer decreases leakage current and defect-trapped charge density, enhancing the reliability and performance of the devices. This study contributes a new organic electronic material, Carmoisine dye, to the literature on semiconductor devices.

Understanding the electronic, structural, optical, photovoltaic and thermoelectric properties of Cs2GeSnBr6 by first-principles and SCAPS-1D simulation

The electronic, optical, structural, thermoelectric and photovoltaic properties of Cs2GeSnBr6 are investigated by using density functional theory and SCAPS-1D simulation. There is a lack of imaginary frequency in the phonon dispersion band structure implies that Cs2GeSnBr6 is stable against lattice distortion. Also, Goldsmith tolerance factor (τ), octahedral factor (µ), and convex-hull calculations demonstrated that Cs2GeSnBr6 can be synthesized. In addition, electronic band structure calculation using GGA-PBE+mBJ+SOC shows that Cs2GeSnBr6 has a direct band gap value of 1.01 eV. Further, optical calculations revealed the higher value of absorption coefficient (α) and optical conductivity (σ) of Cs2GeSnBr6. Motivated by this, we have modelled the ITO/ZnO/Cs2GeSnBr6/Au photovoltaic cell which shows a maximum power conversion efficiency of 18.74%. Moreover, the obtained large ZT value Cs2GeSnBr6 which is originating from its good electrical conductivity with poor thermal conductivity.

Structural, morphological and photoluminescence properties of Eu3+ doped Cd2Sr(PO4)2 nanopowder

Eu3+ doped cadmium strontium phosphate (Cd2Sr(PO4)2CSP) Nanopowder was synthesized by a simple and well known solid-state reaction method (SSR). The prepared nanopowder was characterized by various analytical techniques such as powder X-ray diffraction (P-XRD), scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) studies analysis along with photometric. Based on the results of XRD, the typical crystallite size of the as-prepared nanopowder is found to be 20 nm. The morphological study reveals that the sample has uneven distribution of nano-flakes like structure. The existence of vibrational bands of phosphate ions in the sample were identified by FT-IR spectroscopy. The DRS studies reveal that the sample has wide optical direct bandgap value of 5.4 eV. The Photoluminescence studies showed that the CSP nanopowder sample doped with Eu3+ ions exhibit six distinct emission bands which are ascribed to electronic transitions arose from 5D0 – 7FJ(J=0,1,2,3,4,5) corresponding to wavelengths 538 nm 588 nm, 612 nm, 651 nm, 698 nm and 724 nm respectively. In the present work it was found that the electronic transition from 5D0 → 7F2 at 612 nm (ED) is more intense than the transition from 5D0 → 7F1 at 588 nm (MD) resulting in Eu3+ ions asymmetry nature around the host site. The Photometric parameters like CIE chromatic coordinates, Color Correlated Temperature (CCT), Color Rendering Index(CRI), and Color purity(CP) reveals that the Eu3+ doped CSP nanopowder ions has potential application in the field of solid state lighting.

Deposition of stoichiometry – tailored amorphous Cu-S thin films by MOCVD technique

ABSTRACT Deposition technique and associated deposition parameters play significant roles in determining the stoichiometry of thin films, and consequently, their properties. Herein, Cu-S thin films were deposited on a sodalime glass substrate via metal organic chemical vapour deposition (MOCVD) at temperatures between 350 and 450°C using a single solid source precursor. The deposited Cu-S films were characterized using Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–visible spectrophotometry, and four-point probe technique. RBS characterization revealed that the films are non-stoichiometry while thickness increased from 480 to 655 nm as deposition temperature increased. SEM revealed micrographs that are temperature-dependent. A direct band gap value between 2.75 and 3.80 eV was obtained as the deposition temperature increased. Electrical characterization showed ohmic characteristics in which, resistivity decreased from 18.50 × 10−3 Ωcm to 8.20 × 10−3 Ωcm as deposition temperature increased.

Tuning band gap, structural and optical properties of tin selenide nanoparticles by alkali metal doping

The layered chalcogenide semiconductor, Tin monoselenide is an extraordinary candidate among chalcogenide materials because of their novel physical and chemical properties and tremendous applications in thermoelectrics, solar cells, energy storage devices, i.e. metal–ion batteries, supercapacitors etc. In this work, we synthesized polycrystalline SnSe by a simple hydrothermal method using sodium borohydride as a reducing agent for the single phase formation of SnSe nanostructures. X–ray diffraction spectroscopy has been done to confirm the orthorhombic structure and single phase formation. Fourier transform infrared characterization has been done to observe the linkage of groups among the precursors and solvents used. Further, Photoluminescence characterization has been done to estimate the band gap values and radiative recombination mechanism of the material. Ultraviolet–Visible (UV–Vis) spectroscopy has been used to study the optical properties of the material. Moreover, extrinsic heteroatom doping of sodium and potassium have been done to form NaxSnx-1Se and KxSnx-1Se respectively, which further decreases the band gap of the host material. The absorbance spectra, percentage of transmittance, extinction coefficient, direct band gap values depend upon photonic interactions and has been determined by UV–Vis spectroscopy. Elemental composition of each sample has been confirmed by EDX spectroscopy. All these properties have made the material a potential candidate for opto–electronic and photovoltaic applications.

Organic–Inorganic Manganese (II) Halide Hybrid Combining the Two Isomers Cis/Trans of [MnCl4(H2O)2]: Crystal Structure, Physical Properties, Pharmacokinetics and Biological Evaluation

A manganese (II) complex templated by hexahydro-1,4-diazepinediium as a counter ion was grown by slow evaporation from an aqueous solution at room temperature. The X-ray diffraction analysis revealed that the compound (C5H14N2)[MnCl4(H2O)2] crystallizes in the centrosymmetric space group P2/c of the monoclinic system. The crystal structure of the Mn(II) complex is characterized by an alternation of 0-dimensional organic and inorganic stacks linked together by N/O-H…Cl and N-H…O hydrogen bonds, which lead to a three-dimensional supramolecular architecture. In this structure, the inorganic layer is built up by independent anionic moieties combining the two isomers cis/trans of [MnCl4(H2O)2]2−. The thermal decomposition was studied by TGA-DTA techniques. The optical band gap and Urbach energy were obtained by Tauc’s equation. The direct and indirect band gap values are found to be 4.58 and 4.44 eV, respectively. Weak antiferromagnetic interactions are present in the molecule under study, according to magnetic measurements. An agar well diffusion technique was used to assess the synthetic compound’s biological activity, and the results showed that it has potent antibacterial (Gram-positive and Gram-negative) properties. Interestingly, the synthesized compound also displayed antilipase activity. These biological activities have been confirmed by the bioavailability and pharmacokinetic analyses.

Electrocatalytic Degradation of Rhodamine B Using Li-Doped ZnO Nanoparticles: Novel Approach.

In this paper, we discuss the preparation of Li-doped ZnO nanostructures through combustion and report on their structural, morphological, optical, and electrocatalysis properties. X-ray diffraction analyses show that the samples have a structure crystallized into the usual hexagonal wurtzite ZnO structure according to the P63mc space group. The scanning electron microscope images conceal all samples' nanosphere bundles and aggregates. The reflectance spectra analysis showed that the direct bandgap values varied from 3.273 eV (for pure ZnO, i.e., ZnL1) to 3.256 eV (for high Li-doped ZnO). The measured capacitance concerning frequency has estimated the variation of dielectric constant, dielectric loss, and AC conductivity against AC electric field frequency. The dielectric constant variations and AC conductivity are analyzed and discussed by well-known models such as Koop's phenomenological theory and Jonscher's law. The Raman spectra have been recorded and examined for the prepared samples. Rhodamine B was electro-catalytically degraded in all prepared samples, with the fastest time for ZnL5 being 3 min.

Structural stability, mechanical, and optoelectronic properties of A2TlBiI6 (A = Cs and Rb) for energy harvesting: A first principles investigation

Halide double perovskite materials have potential application in renewable energy devices. Herein, the optoelectronic properties and mechanical stability of A2TlBiI6 (A = Cs and Rb) determined using density functional theory utilizing WIEN2k code have been presented. The traditional and recently modified versions of the tolerance factors have helped identify these compounds as structurally stable, whereas the enthalpy and positive values of the frequency of phonon dispersion indicate the dynamical stability of these perovskite materials. Density of states and band structure calculations indicate that the electronic transition occurs from the top of the valence band [Tl(6p)+Bi(6p)+I(5s)] to the bottom of the conduction band [Tl(6p)+Bi(6p)]. These electronic transitions are responsible for inherently direct band gap at the Γ-point of the first Brillouin zone. The energy band gap calculations for Cs2TlBiI6 and Rb2TlBiI6 give direct band gap values of 2.0 and 2.1 eV, respectively. Our results show that Tl–Bi based double perovskites exhibit considerable stability, suitable band gaps, and excellent light absorption. In particular, direct band gap materials are very promising for use in a multi-junction solar cell. We hope that our work will stimulate the interest of experimental and theoretical experts to synthesize new materials for the solar industry.

Giant band gap bowing in two dimensional Pb[formula omitted]Sn[formula omitted]O alloys and Janus PbSnO monolayers

Two-dimensional monolayer alloys can be experimentally synthesized and the monolayer form of α-PbO and ultrathin SnO were recently synthesized. The band gap values of the materials can be tuned by varying the host atom composition by foreign atoms. Thus, desired band gap value can be obtained for various applications. In this study, we investigated electronic, mechanical and vibrational properties of energetically the most stable Pb1−xSnxO monolayer alloys and dynamically stable Janus PbSnO (J-PbSnO) monolayer using first-principles density functional theory calculations. We found that seven Pb1−xSnxO monolayer alloys can be synthesized by the exothermic reactions. However, to synthesize J-PbSnO monolayer, experimentally suitable environment conditions requires such as which is done to synthesize J-MoSSe monolayer. We found both with PBE and HSE06 functionals that PbO and Pb0.75Sn0.25 compounds have direct band gap values while the remaining compounds have indirect band gap values. In addition, the band gap values of Pb1−xSnxO monolayer alloys do not scale linearly with the changing of the composition and exhibit giant band gap bowing. This non-linearity is attributed to electronegativity and atomic radius differences between Pb and Sn atoms. In addition, we observed that in Pb1−xSnxO monolayer alloys localization of valence band maximum states are mostly distributed among Sn pz orbitals whereas the conduction band minimum states localized around Pb px and py orbitals by the increasing of Sn concentration. We believe that our theoretical predictions will guide the experimental realization of these Pb1−xSnxO monolayer alloys for various applications.

Comparative Study on Structural and Optical Properties of Se85Te6Bi9 Nano-Thin Films Synthesized at Disparate Ambient Argon Pressures

In this research work, we have synthesized amorphous Se85Te6Bi9 Chalcogenide Glasses (ChGs) using Melt Quenching Technique. The glassy nature of the synthesized specimen was confirmed by the DSC thermogram plotted at the heating rate of 20 K/min. The nano-thin films of such synthesized samples at two disparate working pressures (1 torr and 3 torr) of ambient argon gas were made using the Physical Vapour Condensation Technique on the ultrasonically cleaned glass substrates. During the synthesis process of nano-thin films substrate temperature (77 K) was kept constant using liquid nitrogen and the thickness of prepared thin films was 40 nm. The morphological analysis of the prepared nanochalcogenide thin films using FESEM confirmed the nanochalcogenide particle size ranges from 20–80 nm. More aggregation and reduction in particle size on the substrates were observed with an increase in working pressure for Se85Te6Bi9 nano-thin films. HRXRD pattern confirmed the amorphous nature of the synthesized nano-thin films. Based on UV-Visible spectroscopy, the optical parameters such as optical absorption coefficients, optical direct band gaps and extinction coefficients were measured for synthesized Se85Te6Bi9 nanochalcogenide thin films. The value of absorption coefficients and extinction coefficients increases with the increase of ambient argon pressure, whereas the value of the optical direct band gap increases with increasing working pressure due to the quantum size effect and dominance of coulombic interactions. The estimated value of optical direct band gaps are 1.37 eV and 1.47 eV at 1 Torr and 3 Torr respectively making our synthesized nano-thin films a preeminent candidate for solar cell applications and other photonic devices.