查看更多>>摘要：This study examines the linear and nonlinear optical (NLO) properties and thermo-optical aspects of CH3NH3PbI3 (MAPbI3) and MAPbI3 + MOF(UiO-66-NH2), a metal-organic framework (MOF) which are synthesized in the form of a thin layer and characterized by the Z-scan method in various incident powers. The incorporation of the MOF has resulted in increased grain size and crystallinity, while the improvement in both slow and fast decay lifetimes suggest a reduction the defects on the MAPbI3 + MOF surface. The results obtained from the nonlinear behavior show the phenomenon self-focusing behavior and a substantial enhancement in MAPbI3 + MOF thin films relative to MAPbI3 films, primarily attributed to saturable absorption (SA). Furthermore, the parameters measured in the nonlinear refraction index (NLR, n2) and the nonlinear absorption coefficient (NLA, beta) of the MAPbI3 thin film increase with the incorporation of MOF and as the input laser power rises from 10 mW to 50 mW. The enhancement of laser intensity, coupled with the integration of metal-organic frameworks (MOFs) within the perovskite material, has significantly improved the figure of merit (FOM) parameter. This study thus underscores the potential of using MAPbI3 combined with UiO-66-NH2 across a wide array of optoelectronic applications, including Q-switching, demonstrating exceptional NLO properties at reduced incident power levels.
查看更多>>摘要：Vanadium dioxide (VO2) is a promising candidate for thermochromic smart windows for its thermally induced metal-to-insulator phase transition properties. Tungsten doping can reduce the phase transition temperature of VO2 (W-VO2) to near room temperature but deteriorates the thermochromic performance. A W-VO2@AA coreshell structure was proposed to improve the thermochromic performance by enhancing the luminous transmittance and solar modulation, simultaneously. The W-VO2@AA core-shell structure was prepared by the hydrothermal method based on the surface molecular coordination effect, and the shell thickness of AA was modulated by glacial acetic acid. The phase transition temperature of W-VO2@AA is 34.53 degrees C. The solar modulation of the W-VO2@AA/PVP composite film-based smart windows is increased by 80.2 % (from 5.65 % to 10.18 %) compared with W-VO2/PVP, and the luminous transmittance is maintained satisfactorily at 70.52 %. This enhancement is primarily attributed to the injection of electrons from AA into the W-VO2 lattice, which enhances the localized surface plasmon resonance absorption performance. Moreover, the refractive index of AA is between PVP and W-VO2, which decreases the reflectance. This work provides a new strategy to overcome the trade-off relationship between the two thermochromic properties of W-VO2.
查看更多>>摘要：In this study, ZnO thin films were spin coated on FTO coated glass substrates with varying precursor molarities (0.3 M, 0.5 M, 0.7 M, and 0.9 M). The impact of molarity on the structural, morphological, optical, and electrical properties of the films was comprehensively investigated. X-ray diffraction (XRD) patterns confirmed the hexagonal wurtzite structure of the films, with optimal crystallite size and reduced dislocation density for 0.7 M films. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) revealed uniform film growth with roughness values ranging from 4.6 nm to 9.2 nm. UV-visible spectroscopy showed an absorption edge in the near UV region. Schottky diodes were fabricated using Ni as the top contact. The I-V characteristics showed nonlinear behaviour with a rectification of 2 orders for 0.5 M and 0.7 M films. The photoresponse studies indicated significant photocurrent enhancement under UV illumination, with the 0.7 M sample exhibiting a responsivity of 3.5 A/W and detectivity of 2 x 1011 Jones. Transient response analysis demonstrated fast switching behaviour with rise and decay times of approximately 3 and 7 s, respectively.
Navya, N.Krushna, B. R. RadhaSharma, S. C.Sumathi, S....
1.1-1.22页
查看更多>>摘要：This study explores the synthesis, characterization, and multifunctional applications of Sm3+ doped V2O5 nanoparticles (NPs) with varying concentrations (1-5 mol %). The optimized composition of 3 mol % Sm3+ doping exhibited exceptional structural, optical, and photoluminescence (PL) properties, making it suitable for diverse applications. The optimized V2O5:3Sm3+ NPs showed a CCT of 5788 K, a CRI of 92, and CIE coordinates of (0.326, 0.342) at 300 mA. In forensic science, the V2O5:3Sm3+ NPs achieved precise visualization of latent fingerprints (LFPs) at all three levels of detail on various substrates without post-treatment. The NPs revealed critical features such as ridge characteristics and sweat pores, essential for accurate personal identification. Additionally, the You Only Look Once version 8 (YOLOv8x) deep learning model integrated with these NPs provided rapid and precise analysis of Finger print (FP) minutiae, including bifurcations and ridge ends, with high accuracy and robust detection performance. In biomedical applications, the V2O5:3Sm3+ NPs exhibited potent antioxidant activity by scavenging free radicals and restoring oxidative stress (OS) markers in NaNO2 induced RBC models. Their anti-inflammatory properties were evident through the inhibition of protein denaturation and membrane stabilization, while their anti-platelet activity demonstrated significant inhibition of ADP-induced platelet aggregation. The non-toxic nature and multifunctional capabilities of these NPs make them promising candidates for managing OS related conditions, inflammation, and thrombosis. This study underscores the versatility of V2O5:3Sm3+ NPs, establishing them as valuable materials for optoelectronic, forensic, and biomedical applications. Their combined properties open new avenues for advanced technological and therapeutic innovations.
Al-Qahtani, Salhah D.Al-Senani, Ghadah M.Al-Wallan, Amal A.
1.1-1.10页
查看更多>>摘要：New photoluminescent coatings were developed for safety applications using an acrylic emulsion combined with cellulose nanofibers (CNF; 15-28 nm) and rare-earth doped strontium aluminate (RSA) nanoparticles (8-22 nm). The impact of the RSA content on the coating formulation features was examined. CNF serves as a compelling reinforcing material for coatings due to its unique characteristics, including biodegradability, renewability, and biocompatibility. The prepared coatings were applied to tinplate panels. RSA was synthesized in its nanosized form, as characterized by transmission electron microscopy (TEM), to enhance its distribution and functional properties within the coating formulation. The prepared coatings were analyzed using X-ray fluorescence (XRF), energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The transparency and coloring properties of the coating films were analyzed using photoluminescence spectra and three-dimensional coloration measurements. An emission peak was detected at 517 nm upon excitation at 365 nm. The scratch resistance, superhydrophobic properties, and corrosion resistance were examined. CNF was identified as a crucial element in the anti-corrosion efficacy. The provided acrylic emulsion paints exhibited favorable outcomes when combined with cellulose nanofibers and sodium hexametaphosphate. The most prolonged luminescence emission was monitored for almost 60 min in darkness for the RSA content of 12 % (w/w).
查看更多>>摘要：Organic-inorganic hybrid perovskite phenylethylammonium lead bromide has demonstrated exceptional photoelectric performance in the ultraviolet spectrum, yet its potential in the visible spectrum remains largely unexplored. This study presents a comprehensive investigation of visible-infrared broadband photodetection and terahertz modulation utilizing phenylethylammonium lead bromide (C6H5CH2CH2NH3)2PbBr4, (PEA)2PbBr4) single crystals. We have developed and implemented three distinct crystallization techniques to fabricate bulk, film, and needle-like single crystal samples, enabling thorough exploration of their properties across the visiblenear-infrared spectrum (405 nm-780 nm). The carrier dynamics and modulation characteristics of (PEA)2PbBr4 single crystals were meticulously examined through a non-contact terahertz time-domain spectroscopy pumping system, providing insights into the fundamental mechanisms of charge carrier generation. Our experimental findings demonstrate that (PEA)2PbBr4 single crystals exhibit significant potential for application in visible-nearinfrared broadband photodetectors, offering promising avenues for future optoelectronic device development.
查看更多>>摘要：Current research on rare-earth-doped phosphors often faces challenges related to thermal stability, energy transfer efficiency, and color purity, which limit their practical application in lighting technologies. In this study, we address these issues by synthesizing a series of thermally stable Sr2ZnSi2O7: Er3+ (SZSi: Er3+) phosphors via the high-temperature solid-state reaction method. X-ray diffraction (XRD) confirmed the formation of a tetragonal crystalline phase (space group: P-421m) however, scanning electron microscopy (SEM) revealed comprehensive surface morphology and particle size distribution of irregularly shaped particles. Diffuse reflectance spectroscopy (DRS) was used to calculate the optical band gap of the synthesized phosphors. The photoluminescence (PL) studies demonstrated efficient near-ultraviolet (n-UV) excitation (lambda(ex) = 378 nm). Energy transfer analysis using the Dexter theory and the Inokuti-Hirayama (I-H) model indicated that dipole-dipole interactions dominate the energy transfer process between Er3+-Er3+ ions. The optimized SZSi: Er3+ phosphor exhibited high color purity (96 %) with Commission Internationale de l'Eclairage (CIE) chromaticity coordinates of (0.3279, 0.6651) under lambda(ex) = 378 nm. The upconversion luminescence intensity at 661 nm [F-4(9/2) -> I-4(15/2) (Er3+)], when excited at 980 nm, was enhanced with a higher magnitude when increasing the doping concentration from 1 to 10 mol% of Er3+ ions. The dependence of the laser pump power concerning the upconversion luminescence intensity depicts that the emission at 661 nm is due to a two-photon absorption process. In addition, under 980 nm, visible upconversion emissions (in the green and red regions) were observed, attributed to a two-photon absorption mechanism involving intermediate energy levels of Er3+ ions. Thermal quenching analysis demonstrated a moderate decrease in emission intensity (similar to 24 % at 100 degrees C and similar to 36 % at 150 degrees C), suggesting reasonable thermal stability. These findings underscore the potential of Er3+-activated Sr2ZnSi2O7 phosphors in non-display photonic applications, such as bioimaging, anti-counterfeiting, or infrared-pumped display technologies.
查看更多>>摘要：As a potential Fenton catalyst, Fe-based organic frameworks (Fe-MOFs) severely limit their application in practical heavy pollution due to their slow cycling rate. In this work, a novel photocatalyst (NH2-MIL101(Fe, Cu)/WO3) was synthesized using a two-step hydrothermal method. Research on photocatalytic activity revealed that NH2-MIL101(Fe, Cu)/WO3, when combined with H2O2, exhibits higher degradation efficiency compared than pure NH2-MIL101(Fe, Cu) or WO3 alone, achieving up to 90 % degradation of levofloxacin (LEV) under visible light irradiation. In addition, the effects of hydrogen peroxide dosage, pH and other factors on degradation performance were studied, and the results demonstrated good stability even after multiple cycles. This excellent photocatalytic performance is attributed to the formation of heterogeneous structures as well as the doping of copper ions. This not only inhibits the electron-hole recombination, but also improves the redox capacity of the catalyst accelerating the regeneration of Fe3+. This work offers a way to enhance the photo-Fenton activity of Fe-MOF-based catalysts.
查看更多>>摘要：Photo- and radio-luminescence and scintillation properties of Y1.75Gd1.25Al2.8Ga2.2O12:Ce,Mo (Mo = 0, 40, 100, 200 ppm) single-crystalline films grown by the isothermal liquid phase epitaxy technique and microcrystalline powders (Mo = 0 and 600 ppm) were investigated. The onset temperature at 375 K for luminescence quenching was determined from the temperature-dependent photoluminescence kinetics. Under excitation with 5.5 MeV alpha particles, the Y1.75Gd1.25Al3Ga2O12:Ce,Mo40 exhibited the highest light yield of 8900 photons/MeV and energy resolution of 4.8 % along with scintillation decay times of 115 ns (20.3 %) + 967 ns (29.9 %) + 2825 (49.8 %).
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