Optical Absorption Characteristics Research Articles

Large depth-of-field ultraviolet-visible photoacoustic histologic and microvascular imaging in vivo

Photoacoustic microscopy (PAM) can image diverse biological microstructures by harnessing characteristic optical absorption spectra of intrinsic nonfluorescent biomolecules. We incorporate ultraviolet (UV) and visible pulsed lasers into a PAM to develop an UV-visible PAM for label-free histologic and microvascular imaging, where the cell nuclei and blood vessels are specifically captured at high contrast relying on strong optical absorption of DNA/RNA and hemoglobin at 266 and 532 nm wavelengths, respectively. Moreover, two diffractive optical elements operating at UV and visible spectra are designed for engineering the excitation beams, significantly enlarging depths of field (DOFs > 200 μm). The UV-visible PAM demonstrates combined capabilities of dual imaging contrast, elongated DOFs, and micrometer-scale lateral resolution for delineating the spatial microarchitectures of both cell nuclei and blood vessels that are at different depth locations in the biological specimens with uneven surfaces. Longitudinal monitoring of the trauma is performed in mouse ear in vivo. Potentially, our UV-visible PAM could offer comprehensive histologic and microvascular information in a broad range of biomedical studies.

Nonlinear optical properties of some nanosized ammonium dihydrogen phosphate crystals incorporated in aluminum oxide nanopores

This study explores the nonlinear optical properties of aluminum oxide (Al2O3) matrices embedded in ammonium dihydrogen phosphate (ADP) nanocrystals using third-harmonic generation (THG) techniques. The successful integration of ADP crystallites within the nanopores of the Al2O3 matrix was confirmed using x-ray structural analysis and electron microscopy. The optical absorption characteristics were examined over a wide wavelength range, revealing that the reflection and transmission spectra were notably affected by pore size and surface scattering effects. THG measurements conducted with a high-intensity infrared laser demonstrated a pronounced third-order nonlinear response, whereas second-harmonic generation was not observed. The absence of SHG can be attributed to phase mismatch and inherent material properties, including centrosymmetry and surface roughness. The comparative and Reintjes models were used to calculate the third-order nonlinear optical susceptibilities. Among these, the Reintjes model provided the most accurate fit for the experimental data. This research underscores the considerable influence of nanopore size on THG efficiency, highlighting the importance of light scattering and phase-matching conditions. These findings contribute to a growing body of knowledge regarding nonlinear optical phenomena in nanocomposite materials and offer valuable insights for future applications in photonic devices. This comprehensive analysis highlights the potential of Al2O3 matrices with embedded ADP nanocrystals to advance the field of nonlinear optics in nanocomposite materials and offers insights for prospective applications in photonic devices.

Structural, optical absorption and electrical characteristics of sol-gel synthesized chromium-doped bismuth ferrites

Multiferroic materials have remarkable and several technical uses such as random-access multi-state memories, solar cell devices, data storage recording technologies, etc. An attempt has been made here to synthesize chromium-doped Bi(Fe1-xCrx)O3 (x = 0–0.10) oxides via citrate based sol-gel route and characterized with regards to structural, optical absorption and electrical properties. It depicts a rhombohedral structure with space group R3c for BiFeO3 and Bi(Fe0.98Cr0.02)O3 compositions. The lattice parameters for BiFeO3 on rhombohedral axes are aR ∼5.796 Å, α ∼59.34° which decreases linearly with chromium (x). Similarly, the parameters on hexagonal axes also decrease as aH ∼5.739–5.730 Å, and cH ∼14.269–14.262 Å. However, chromium doping causes a drop in crystallite size and rise in dislocation density. The absorption spectra show a broad peak at λ = 392 nm (for x = 0) and a broader as well as high intense peak for x = 0.02 (λ∼ 393 nm) which is attributed to charge transfer transitions from O2− (2p) valence band to Fe -3d (eg and t2g split levels) conduction band. Band at λ ∼310 nm is associated to the band gap (Eg) of material. Composition Bi(Fe0.98Cr0.02)O3 (x = 0.02) exhibits the highest values of the dielectric constant (εr ∼ 1102), loss (tan δ ∼ 1.1), and least value of impedance. The Cole-Cole plot depicts a depressed semi-circle and indicates presence of loss due to grains only. The room temperature P–E hysteresis loop with remanent polarization (Pr = 0.11439 μC/cm2) and leakage current density (J = 1.1 μA/cm2) are found maximum for Bi(Fe0.98Cr0.02)O3 (x = 0.02). The I-E loop and frequency-dependent P-E loops depict ferroelectric nature of all compositions. The analysis of leakage current density and slope values infer the presence of space charge limited conduction (SCLC) mechanism. These findings suggest materials applications in recent technologies.

Extragalactic globular cluster near-infrared spectroscopy

Context. One way to constrain the evolutionary histories of galaxies is to analyse their stellar populations. In the local Universe, our understanding of the stellar population properties of galaxies has traditionally relied on the study of optical absorption and emission-line features. Aims. In order to overcome limitations intrinsic to this wavelength range, such as the age-metallicity degeneracy and the high sensitivity to dust reddening, we must use wavelength ranges beyond the optical. The near-infrared (NIR) offers a possibility to extract information on spectral signatures that are not as obvious in traditional optical bands. Moreover, with the current and forthcoming generation of instrumentation focusing on the NIR, it is mandatory to explore possibilities within this wavelength range for nearby-Universe galaxies. However, although the NIR shows great potential, we are only beginning to understand it. Widely used techniques such as a full spectral fitting and line strength indices need to be tested on systems that are as close to simple stellar populations as possible, and the result from the techniques need to be compared to the yields from a traditional optical analysis. Methods. We present a NIR spectral survey of extragalactic globular clusters (GCs). The set was composed of 21 GCs from the Centaurus A galaxy that were obtained with SOAR/TripleSpec4, which covered the ∼1.0–2.4 μm range with a spectral resolution (R = λ/Δλ) of 3500. These spectra cover Hβ equivalent widths between 0.98 Å and 4.32 Å, and [MgFe]′ between 0.24 Å and 3.76 Å. Results. This set was ideal for performing absorption band measurements and a full spectral fitting, and it can be used for kinematic studies and age and abundance measurements. With this library, we expect to be able to probe the capabilities of NIR models, as well as to further improve stellar population estimates for the GCs around the Centaurus A galaxy.

Hydrothermally Synthesized TiO2-Doped MnO2 Nanocomposites for Electrochemical and Photocatalytic Activity

In our study, we synthesize titanium oxide (TiO[Formula: see text] and manganese dioxide (MnO[Formula: see text] using hydrothermal methods, which are TiO2-doped MnO2 nanoparticles. In order to evaluate the essential optical and electronic properties of the proposed nanostructures, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transformation infrared analysis (FTIR), Ultra–Visible infrared spectroscopy (UV–Vis), and Photoluminescence (PL) were applied. Based on the results of the SEM investigation, nanostructures form crystal structures when different compositions are used. It was also confirmed that TiO2 derivatives were produced from the fabricated nanoparticles by their spectral and optical absorption characteristics. During electrochemical measurements, it was found that MnO2 nanocomposite samples doped with TiO2 had a markedly reduced charge transfer resistance, suggesting that electrons and holes were effectively separated by photo-stimulation. Aqueous solutions based on wastewater were shown to be degraded by TiO2-doped MnO2 nanoparticles when irradiated with visible light. It was demonstrated that nanocomposites composed of TiO2-doped with MnO2 and having reduced bandgap could be used for the removal of organic dyes from aqueous solutions as well as wastewater treatment were reported in detail.

Opto-electronic responses of large area WSe2 layers synthesized by chemical conversion of WO3 thin films

Atomically thin tungsten diselenide (WSe2) has drawn much interest due to its remarkable optical properties and potential applications in next-generation optoelectronics and energy harvesting devices. High-quality, wafer-scale synthesis of such two-dimensional (2D) semiconductors is necessary for their practical applications. Chemical vapor deposition (CVD) is a promising method for synthesizing large-area thin films of 2D materials where the constituent elements are of widely different vapor pressure. Herein, we demonstrate large-area synthesis of the 2H phase of WSe2 with a precise control over the 2D film thickness. The first step of this process is the deposition of tungsten trioxide (WO3) films of a well-defined thickness by thermal evaporation over large areas. The subsequent selenization of these films in an atmospheric pressure CVD reactor, yields high-quality uniform films of WSe2. The quality of these films is ascertained by measuring their characteristic Raman active vibrational modes and layer thickness dependent optical absorption and photoluminescence. The photoconductivity (PC) of these films has been measured with 405, 532 and 915 nm laser excitation. We note an increase in the PC of the films with their thickness. The best photoresponsivity and detectivity obtained are 11.3 mA/W and 1.42 × 108 Jones respectively. These results are promising to create photo-transistor arrays over large areas using such WO3 processed films.

A deterministic mechanism for efficient removal of arsenic and lead from wastewater using rapidly synthesized TiO2-(α-Fe2O3) nanoshells

Removal of heavy metals from wastewater using efficient techniques became demanding wherein various nanomaterials with tailored physicochemical traits can be useful. Thus, PLAL approach at an optimum laser energy was used to make TiO2-(α-Fe2O3) nanoshells (TFNSs) by mixing nanoparticles (NPs) suspension of TiO2NPs (TNPs) and α-Fe2O3NPs (FNPs) at 50 to 50 ratio. The produced nanocomposites were customized by targeting Ti that was submerged in deionized water as growth medium and then irradiate using the laser pulses with an optimum laser energy 10.6 J/cm2, spot focused size of 1.2 ± 0.2 mm, frequency of 6 Hz, and laser beam with a pulse duration of 8 ns for 15 minutes. In the course of the ablation process, the solution was agitated to achieve the formation of TNPs, FNPs, and TFNSs by preventing the formation of craters on the target surface. The obtained NSs were characterized to evaluate their structural, morphological, optical absorption and fluorescence characteristics. TEM micrographs of the liquid suspension confirmed the existence of spherical nanocrystallites of TiO2-(α-Fe2O3)NSs with mean diameter ≈12.4 ± 1.31 nm. XRD and FTIR results have been used to identify the samples crystalline nature and high purity. LSPR absorption bands of TFNSs were evidenced at 230 to 300 nm. These NSs showed prominent fluorescence peaks escorted with blue shift. Arsenic and lead removal efficiency of TFNSs from wastewater was better (over 99% at pH = 9) than TNPs and FNPs. The removal of arsenic and lead from wastewater by TNPs, FNPs and TFNSs were explained using a possible mechanism. The obtained results suggest that the proposed NSs can be potential for wastewater treatment, contributing towards sustainable growth.

On analysis of structural and optical absorption characterization of Bi35Sb5Se60 nanostructured thin films for photosensing application

In this extensive study, the primary focus is directed towards the intricate exploration of the optical absorption characteristics inherent in nanostructured Bi35Sb5Se60 thin films, prepared by thermal evaporation under a vacuum of 10−5 Torr, ensuring high purity and uniformity for optoelectronic applications. With a particular emphasis on their prospective application in photosensing devices. The research employs a comprehensive approach, integrating various spectrophotometric measurements that encompass both transmission and reflection analyses. The meticulous examination of the absorption edge characteristics reveals a direct energy gap of 1.82 eV, providing a foundational understanding of the material's electronic structure. The determination of the dispersion energy at 6.35 eV and the oscillator energy at 2.96 eV further enriches the understanding of the material's optical behavior, shedding light on its capacity to interact with incident light. A noteworthy highlight emerges with the identification of high photosensitivity exhibited by the heterojunction, particularly under lower reverse bias conditions, underscoring its potential utility in photosensing applications. The PL spectra reveal a highly broadened defect emission band with peaks at 475 nm, 490 nm, and 540 nm, providing insights into the recombination processes within the material. The identification of emission peaks related to the conduction band edge and acceptor levels further enhances the comprehension of the material's optical and electronic characteristics. underscores the potential of these nanostructured thin films for efficient photosensing devices. The findings presented in this research not only advance the understanding of the material's properties but also lay a robust foundation for further research and development in the design and optimization of photoresponsive devices within the realm of optoelectronic technologies.

Direct Z-scheme GeC/GaSe heterojunction by first-principles study for photocatalytic water splitting

In this study, we constructed the direct Z-scheme heterojunction by vertically stacking monolayers of GeC and GaSe. And systematically explored its stability, electronic structure, optical absorption characteristics and photocatalytic mechanism with first principles calculations. Our results show that the GeC/GaSe heterojunction possesses an indirect-gap of 1.88 eV and exhibits a staggered energy-band structure. In comparison to the individual monolayers of GeC and GaSe, the GeC/GaSe heterojunction has more excellent absorption of far-ultraviolet and visible light. And the electrons and holes in the GeC/GaSe heterojunction have a transmission path resembling the letter Z. There is also an internal electric field from GeC to GaSe in the heterojunction, which accelerates the photoelectrons and holes along the Z direction when the heterojunction receives light. Furthermore, further studies suggest that the GeC/GaSe heterojunction can be utilized as a photocatalytic material for water splitting under pH = 0–14. Besides, the bandwidth and optical absorption properties of the GeC/GaSe heterojunction can be adjusted by biaxial strains. Moreover, Gibbs free energy calculations during water splitting demonstrate that the GeC/GaSe heterojunction exhibits a highly driven force for both OER and HER. Thus, direct Z-scheme GeC/GaSe heterojunction has the capability to be a promising photocatalyst for water splitting.

Cr-induced structural phase transformation in sputter deposited poly-AlN thin film from wurtzite to rocksalt structure and their effect on the optical properties

We report Cr doping-induced structural phase transformation (PT) in sputter-deposited polycrystalline-AlN thin film from wurtzite (w) to rocksalt (r) structure. Rietveld analysis shows that the steady substitution of Al ions by Cr ions in the w-AlN lattice distorts and compresses the wurtzite lattice along the c-axis. The chemical pressure exerted in the w-AlN lattice by the compression from the doped Cr ions causes the PT, similar to the high-pressure-induced PT in AlN. Post the PT, the r-Al1-xCrxN thin film continues to exhibit compressive residual stress, indicating that such sustained stress may also play a role in stabilizing the metastable r-Al1-xCrxN phase. The structural distortion and the PT also affected the optical absorption characteristics of the w-Al1-xCrxN thin films. The w-Al1-xCrxN exhibit a direct inter-band transition and the band gap (Eg) decreases from ∼ 6.06 eV for pure w-AlN to ∼ 4.15 eV for w-Al0.73Cr0.27N. After the PT, the r-Al0.61Cr0.39N thin film, on the other hand, exhibits an indirect inter-band transition with an Eg of ∼ 1.84 eV. In addition to the change in Eg, a prominent defect band appears at ∼ 4 eV at low Cr% and another band appears at ∼ 0.98 eV at higher Cr%.

Exploring the ON/OFF nonlinear optical (NLO) response in tetracene-based chromophores: A DFT study on solvent and frequency-dependent NLO properties for switching applications

Tetracene-based nonlinear optical (NLO) materials are an ambient field of interest in optoelectronic technology. Inspired by this material, we theoretically designed D-D-A framework molecules (ZO and ZO-1 to ZO-16) with auxiliary donor and acceptor screening of solo tetracene linear surface and investigated their reactivity, electrical properties, solvent-dependent optical and ON/OFF NLO properties utilizing DFT simulations. The CPCM and IEFPCM model is used to examine how entire spectrum of medium polarity, ranging from less polar to more polar solvents (chloroform (ε = 4.71) < tetrahydrofuran (ε = 7.43) < DMSO (ε = 46.83 < water (ε = 78.36)) affect the optical absorption and NLO characteristics (βtot, αtot, and μtot) of suggested compounds (ZO and ZO-1 to ZO-16). Furthermore, natural bond orbital analysis (NBO) and topological analysis (MEP, ELF, and LOL) were used to explain the NLO results. Regarding the charge transfer robustness, ZO-9, a promising tetracene derivative, is identified as an appealing second-order NLO candidate, with the lowest energy gap (1.642 eV) and largest λmax (546.692 nm) among all investigated derivatives. Moreover, the solvent-dependent optical absorption spectrum shows that polar solvent (THF) alleviates the λmax from 273.081 nm to 707.511 nm in ZO-11. Similarly, solvent also influences the NLO properties in all designed compounds, especially in ZO-9, which displayed giant βtotal = 7.244 × 105 in chloroform, 8.640 × 105 in THF, 1.153 × 106 in DMSO, and 1.180 × 106 in water as well as in gas (1.993 × 105). Additionally, the results of the second harmonic generation (SHG) β(−2ω, ω, ω) and the electro-optical Pockels effect (EOPE) β(−ω,ω,0) computed at the frequencies of ω = 1064 nm (0.0428 au) and ω = 532 nm (0.0856 au) validates that all tetracene based derivatives are excellent NLO candidates for laser working condition and switching applications.

In-situ ellipsometric study of WO3–x dielectric permittivity during gasochromic colouration

The complex dielectric permittivity of tungsten oxide at all stages of its colouration in a hydrogen-rich atmosphere was retrieved from measured VIS-NIR ellipsometric spectra of WO3/Pd bilayer. The retrieval was done by fitting the spectra with the Cody-Lorentz dispersion model, and, for optical absorption features, two Gaussian functions were added. The band gap edge, the Gaussian center energies, amplitudes, spectral widths and integrals were traced as the redox reaction progressed. Analysis of obtained data provides insight into mechanism of surface and bulk oxygen vacancies formation. We discuss these peculiarities in detail and show how they do affect the optical constants of WO3–x and potential sensors’ response rates.

Phase transition in Eu2Zr2–xO7–2x (x = 0–1) solid solutions: A combined structural and spectroscopic study

AbstractZirconate pyrochlores have been extensively studied as candidate waste forms for the immobilization of actinide wastes due to their flexible crystal chemistry, excellent structural stability, and exceptional radiation tolerance. Herein, we report the synthesis of a series of compounds Eu2Zr2–xO7–2x (x = 0–1, step = 0.125) using a co‐precipitation route to form solid solutions between the two end members, Eu2Zr2O7 pyrochlore and Eu2ZrO5 defect fluorite. It is important to understand the pyrochlore to defect fluorite transformation as a function of Zr/Ln molar ratio. The structural investigation by x‐ray diffraction has shown the increasing cation disorder and corresponding structural transitions from the ordered pyrochlore to disordered pyrochlore, then to defect fluorite. While diffuse reflectance spectroscopy provides similar optical absorption features reflecting the presence of Eu(III) ion, Raman spectroscopy has revealed more details on the phase transition and short‐range structures. This work highlights the structural flexibility in zirconate materials as potential nuclear waste forms for the immobilization of actinide‐rich waste streams, especially suitable for the separated minor actinides.

Fabrication, Physical, Optical and γ-Ray Absorption Characteristics of Bi3+ Ions Doped Borate Barium Fluoride Ytterbium Glasses: Role of the Substitution of B2O3/Bi2O3 in the Borate Glass System

Fabrication, Physical, Optical and γ-Ray Absorption Characteristics of Bi3+ Ions Doped Borate Barium Fluoride Ytterbium Glasses: Role of the Substitution of B2O3/Bi2O3 in the Borate Glass System

Phase transitions in NiO during the oxygen evolution reaction assessed via electrochromic phenomena through operando UV–Vis spectroscopy

Due to its high activity and stability, nickel oxide (NiO) has shown significant promise as an electrocatalyst for the alkaline oxygen evolution reaction (OER). In parallel, NiO exhibits a well-known electrochromic phenomenon, changing its optical properties in response to an applied electric potential. This study investigates the relationship between NiO phase changes that occur during the OER and the connected optical modulation using operando UV–visible reflectance spectroscopy. The correlation between the OER activity and the electrochromic behavior of NiO is explored, providing insights into the underlying physicochemical mechanisms governing both phenomena. Strong reduction of the reflected light at higher applied potentials cannot be attributed solely to the change in optical bandgap due to the phase change or the change in the material's refractive index when different phases form. Therefore, in-gap states responsible for increasing the absorption at higher applied potentials were experimentally characterized by ultraviolet photoelectron spectroscopy (UPS) and X-ray absorption spectroscopy (XAS). The results show that phase changes in NiO during OER influence its optical absorption characteristics, which in turn give access to following active phase changes of the electrocatalyst material through a non-invasive, optical, operando probe in real time allowing for kinetic studies of the involved solid-state conversion reactions.

Systematic Modeling of N-Type D–A–D Conjugated Small Molecule-Based Nonfullerene Acceptors for Organic Photovoltaics

This study investigates the impact of six novel (SPZ1–SPZ6) small molecular conjugated nonfullerene acceptors (NFAs), for organic solar cells (OSCs). The designed NFAs are characterized by various advanced quantum chemical simulations of density functional theory (DFT) and time-dependent (TD-DFT) approaches. We revealed in-depth information regarding molecules’ structural-property relationship charge transfer and optical absorption characteristics of designed molecules and compared them with synthetic reference molecules (R). The designed SPZ1–SPZ6 molecules exhibit red-shifted absorption, reduced bandgaps and increased extinction coefficients, indicating improved molecular phase separation during thin-film deposition during device fabrication. Moreover, the modeled SPZ1–SPZ6 molecules significantly enhance photophysical, optoelectronic and photovoltaic parameters compared to R. Among these, the designed small molecule SPZ2 exhibits superior UV–Vis absorption of 730.44 nm, surpassing R and others. SPZ2 features the smallest bandgap (2.00 eV) and has a substantial improvement over R’s 2.37 eV, and this is due to our efficient molecular modeling strategy. Further investigation revealed efficient charge transfer between the SPZ2 acceptor molecule and PTB7-Th donor molecule complex, making this design capable of producing efficient OSCs in the future.

Defect‐induced ferromagnetic ordering in pristine cuprous oxide nanocrystals at room temperature

Herein we report the existence of room temperature ferromagnetic ordering in pristine cuprous oxide nanocrystals mediated by native point defects present in the material. To demonstrate defect‐induced magnetism, cuprous oxide nanocrystals were synthesized in a simple and sustainable route employing hydroxylamine as the reducing agent. The crystalline phase of the as‐synthesized nanocrystals was investigated and was found to have crystallized in cuprite crystal structure. The optical absorption characteristics exhibits absorption features in the visible region between 400 and 600 nm signifying the presence of optically active defects. The morphology of the sample was examined, which reveals the shape to be corner‐truncated rhombic dodecahedral and the size to be in the range of 200–250 nm. The field‐dependent magnetization measurement at room temperature indicates the presence of collective ferromagnetism with hysteresis behavior (Ms = 210 memu g−1, Mr = 43 memu g−1, Hc = 16.37 mT) due to exchange interaction between the uncompensated spin moments present on the surface of the material.

Nonlinear Optical Saturable Absorption Properties of 2D VP Nanosheets and Application as SA in a Passively Q-Switched Nd:YVO4 Laser.

Two-dimensional (2D) violet phosphorus (VP) plays a significant role in the applications of photonic and optoelectronic devices due to its unique optical and electrical properties. The ultrafast carrier dynamics and nonlinear optical absorption properties were systematically investigated here. The intra- and inter-band ultrafast relaxation times of 2D VP nanosheets were measured to be ~6.83 ps and ~62.91 ps using the pump-probe method with a probe laser operating at 1.03 μm. The nonlinear absorption coefficient βeff, the saturation intensity Is, the modulation depth ΔR, and the nonsaturable loss were determined to be -2.18 × 104 cm/MW, 329 kW/cm2, 6.3%, and 9.8%, respectively, by using the Z-scan and I-scan methods, indicating the tremendous saturable absorption property of 2D VP nanosheets. Furthermore, the passively Q-switched Nd:YVO4 laser was realized with the 2D VP nanosheet-based SA, in which the average output power of 700 mW and the pulse duration of 478 ns were obtained. These results effectively reveal the nonlinear optical absorption characteristics of VP nanosheets, demonstrating their outstanding light-manipulating capabilities and providing a basis for the applications of ultrafast optical devices. Our results verify the excellent saturable absorption properties of 2D VP, paving the way for its applications in pulsed laser generation.

Exploring the Post-Annealing Influence on Stannous Oxide Thin Films via Chemical Bath Deposition Technique: Unveiling Structural, Optical, and Electrical Dynamics

Stannous oxide (SnO2) thin films have garnered significant attention for their promising applications in various electronic and optoelectronic devices. In this study, we investigate the impact of post-annealing on the structural, optical, and electrical properties of stannous oxide thin films deposited using the chemical bath deposition (CBD) technique. The thin films were prepared on a Borosilicate glass substrate, followed by a controlled annealing process to enhance their performance. Structural analysis was conducted using techniques such as X-ray diffraction (XRD) to examine the cubic crystalline structure and the crystallite size increase induced by post-annealing. The results revealed alterations in grain size from the SEM and the purity of samples confirmed from EDX results. The optical properties of the Stannous oxide thin films were examined using UV-Vis spectroscopy. The optical absorption and bandgap characteristics were analyzed to understand how post-annealing influences the optical behavior of the thin films. Where the optical absorption was 320nm and the bandgap ranges were 3.86eV to 3.83eV. Furthermore, the electrical properties of the thin films were evaluated semiconducting nature, and conductivity increased with rising post-annealing. The findings from this study contribute to the understanding of the role of post-annealing in tailoring the properties of Stannous oxide thin films. The optimization of structural, optical, and electrical characteristics is crucial for their successful integration into electronic and optoelectronic devices.

Development and preparation of novel nano-enhanced organic eutectic phase change materials for low-temperature solar thermal applications

ABSTRACT Thermally reliable and stable eco-friendly Phase change materials are of significant aid in thermal energy storage technology, leading to improved energy utilization and reliability of the system. This study develops two novel organic eutectic PCM of Lauric acid – Margaric acid (LM) and Myristic acid – Margaric acid (MM), which are chemically stable and thermally compatible for latent heat energy storage. LM eutectic mixture had a melting temperature of 52.66°C with a latent heat of 163.68 J/g, and MM eutectic mixture had its melting temperature at 44.79°C and a latent heat of 197.31 J/g. The phase change temperatures were favorable for low temperature solar thermal applications with good latent heat capacity. The thermal characteristics of these eutectic mixtures are further enhanced with the dispersion of highly conductive Multi walled carbon nanotubes (MWCNT) at three different mass fractions (.5%, 1% and 1.5% by weight). Nano enhancement could achieve exceptional thermal conductivity enhancement in MM eutectic mixture by 110.6% and 83.73% in LM eutectic mixture. Thermogravimetric analysis and Fourier-transform infrared spectroscopy analysis ensured the thermal and chemical stability of the eutectic mixtures. The optical absorption characteristics were extensively enhanced with nano particle addition, which is highly preferable in solar thermal applications.