Optical Materials最新文献

With the development of deep space exploration, nuclear medical imaging, high-energy physics experiments, and other fields, the demand for large-size CsI:Na crystals is increasing due to the low cost of use, high light yield, and excellent irradiation resistance of CsI:Na crystals. In this work, we investigated the scintillation characteristics of thirty-five Ø76 mm × 76 mm CsI:Na single crystals, delving into the variation of energy resolution and light yield. Meanwhile, a method based on ¹³⁷Cs source collimation and coupling the crystal to PMT in different directions was used to reveal the uniformity of scintillation performance of large-size CsI:Na single crystals. The Bridgman-grown 51 mm × 51 mm × 152 mm CsI:Na single crystals have an energy resolution of 6.5 % at 662 keV, which does not change significantly regardless of irradiation location or irradiation method.

Interest in composite ceramics based on silicon nitride (Si₃N₄) and aluminum oxide (Al₂O₃) is due to the possibility of using them as semiconductor applications associated with their operation under conditions of external influences, including heating. The paper presents the results of assessing the influence of variations in the phase composition of (1-x)Si₃N₄ – xAl₂O₃ ceramics on alterations in optical and thermophysical parameters, as well as their relationships. Analysis of the optical characteristics of the ceramics under study showed that changes in the phase composition associated with the dominance of the Al₂O₃ phase in the composition of the ceramics lead to a change in covalent bonds and an increase in the number of ionic bonds, which also affects the change in the semiconductor nature of the ceramics, and therefore, a change in the thermophysical properties. According to the assessment of changes in the thermal conductivity coefficient of the studied ceramics, with the dominance of the Al₂O₃ phase in the composition, the observed growth in the concentration of structural defects, as well as oxygen vacancies, results in the thermal conductivity coefficient decrease, as well as an elevation in the thermal expansion of ceramics during thermal heating. It has been determined that the presence of a combination of Al₂(SiO₄)O and Si₃N₄ phases in the ceramic composition leads to an increase in the thermal conductivity coefficient, as well as maintaining its stability over a wide temperature range.

Crystal engineering is critical for improving the crystal quality and tuning the optoelectronic properties of metal-organic frameworks (MOFs) materials. Doping MOFs is one of the practical approaches to improve the optoelectronic properties of MOFs. Here, a simple and effective method is used to grow MOF nanoparticles as films on the surface of the material. MOF-5 and ZIF-8 nanoparticles can be uniformly grown as films on the Si substrates. The crystalline quality of MOF films is improved after doping with Tb. Meanwhile, two-dimensional conducting photodetectors and photodetector arrays were prepared with perovskite films. Meanwhile, planar conducting photodetector arrays were prepared with MOF films. The photoluminescence (PL) intensity of the Tb-ZIF-8 and Tb-MOF-5 films shows an improvement compared to both ZIF-8 and MOF-5 layers, which leads to improved charge carriers transfer. The maximum photocurrents were about 4 × 10⁻⁸ A and 3 × 10⁻⁸ A of exposed light at 525 and 425 nm, respectively, at a fixed bias of 10 V for Tb-ZIF-8. The highest photo response of approximately 2.4 × 10⁻⁷ and 1.2 × 10⁻⁷ A was measured under 525 and 450 nm for the Tb-MOF-5-based device, respectively. The photocurrent behavior is optimized in the visible range due to the increased number of photo-generated carriers at 525 nm. The Tb-MOF-5 based device is a more powerful photodetector than the Tb-ZIF-8 based device under the same conditions. In addition, the stability of Tb-MOF-5 and Tb-ZIF-8 based photodetectors was obtained 77 % and 30 %, respectively. The photodetectors of Tb-MOF-5 have higher stability and better performance than Tb-ZIF-8.

We conducted a study on composites made of polyurethane and graphene (PU-G). We synthesized these composites and then examined their far-field diffraction patterns at various concentrations of dimethylformamide (DMF) using the spatial self-phase modulation (SSPM) method. By analyzing the intensity-dependent far-field ring patterns, we were able to estimate the samples' thermally induced nonlinear refractive index and thermo-optical coefficient. We found that these variables, as well as other observable phenomena such as the “diffraction ring collapse effect” and “variation in nonlinear refractive index,” depended on the sample's concentration rate. Our results indicate that the laser-induced thermal effect is a significant factor in the SSPM phenomena observed in our experiments. Furthermore, our findings suggest that the PU/G combination in DMF has promising nonlinear optical properties that could be beneficial in a variety of nonlinear optics applications.

Here we report a promising whey protein isolate (WPI)-stabilized emulsion microgels for targeted drug delivery into the kidney. Investigation of stability revealed time-dependent degradation of the microgels starting at 72 h. Cytotoxicity studies showing increased sensitivity in Hek239 and Jurkat cells. A biodegradation assay underscored the role of macrophages in the destruction process of microgel particles. The efficiency of targeting the microgels for the kidney was assessed by biodistribution using intravenous and intraarterial delivery. Tail vein administration demonstrated long-term (minimum 5 days) selective accumulation not only in the liver but also in the kidneys. Renal artery injection of microgels resulted in an expected local increase in fluorescence in the target kidney in the first minutes after injection. In contrast, at 1 and 3 h there was an atypical accumulation of the Cy7 fluorescent signal in the opposite kidney. However, at 1 and 5 d the fluorescent signal predominated in the target kidney again and was higher in comparison with intravenous administration. Histological analysis validated the safety of WPI-based microgels using different methods of administration. By fine-tuning the physicochemical properties and delivery methods, the developed microgels offer an adjusted therapeutic approach with reduced side effects. They present new prospects for the treatment of kidney disorders using both intravenous administration and minimally invasive endovascular approach.

In the current Study, undoped and bismuth doped CuO + ZnO coupled oxide thin films were meticulously deposited on glass substrates utilizing the spray pyrolysis technique. The effect of bismuth doping level in the structural, morphological, optical, electrical and electrochemical properties of these thin films were systematically investigated. X-ray diffraction patterns unequivocally confirmed the polycrystalline nature of the films, showcasing a combination of monoclinic CuO and hexagonal wurtzite ZnO phases. Furthermore, at a doping level of 8 %, the presence of the bismuth phase was observed, indicating its incorporation into the CuO–ZnO matrix. As the bismuth doping level increased, we observed a noticeable improvement in crystallinity and grain size. The distinctive characteristics of the developed thin films underscored a discernible enhancement in physical and electrochemical properties with the increase of bismuth doping level. Subsequently, The 8 % bismuth-doped CuO–ZnO thin films exhibit remarkable efficiency in degrading pharmaceutical compounds. Specifically, within a mere 2-h timeframe, these films demonstrate an exceptional degradation efficiency of 99 % towards Rifampicin, a widely used antibiotic. Moreover, their efficacy extends to other pharmaceutical pollutants, showcasing a significant degradation of 77 % for Ampicillin, an antibiotic commonly used to treat bacterial infections, and an even more substantial degradation of 90 % for Rhodamine B, a prominent dye compound. This underscores the promising potential of 8 % bismuth-doped CuO–ZnO thin films in addressing environmental and health-related challenges associated with pharmaceutical contaminants.

Six samarium complexes that radiated orange color, were synthesized with the chelation of organic sensitizer using solvent-assisted grinding method. The complexes were analyzed by various techniques elemental analysis, XRD, FTIR, NMR, UV–visible spectroscopy and photoluminescent spectra in solid and solution states respectively. The calorimetry aspects of the complexes in both states were also determined through the MATLAB software. FWHM values for the corresponding transition were assessed by the Gaussian fitting, which was used to compute the lasing properties. Optical properties and Urbach energy investigation have been done by the diffused reflectance spectra, which suggest that these complexes are good contenders for semiconductor devices. Judd-Ofelt parameter indicates that these complexes possess an asymmetric environment around samarium ion with covalent character and moderate rigidity. For justification of the optical band gap, computational study (HOMO-LUMO) difference was found by DFT calculation in ORCA software. Thermal stability and biological properties of the complexes were also determined.

As a new display mode, laser display is becoming popular in the industry, and it has served our lives. In addition, a new material, perovskite quantum dots(QDs) is more capable of energizing laser displays with a narrow half-peak width, tunable emission and high color purity. Here, by incorporating perovskite CsPb(Br_xI_1-x)₃ quantum dots into the glass, we explored the performance of large-size glass in laser display. It is demonstrated that the sheet of CsPbBr₃ and CsPb(Br_0.25I_0.75)₃ glasses has good wavelength uniformity, and the phosphor wheel with the sheets yields a wide color gamut (its color gamut reaches 124.3 % of NTSC and 91.3 % of Rec.2020), which will play a significant advantage in the field of laser projection.

Thanks to their ability to control light, research on metalenses is developing rapidly. However, it is still quite difficult to design broadband metalenses with high polarization conversion efficiency. In this study, an alternative plasmonic material, aluminum-doped zinc oxide, is presented for metalens operating in near-infrared regime. We propose simple and hybrid metalenses with high polarization conversion efficiency and high transmission values that can focus efficiently in a wide near-infrared bandwidth (700–1000 nm). We design metalens consisting of subwavelength aluminum-doped zinc oxide nanoblocks based the Pancharatnam-Berry phase method and utilizing the finite-difference time-domain method. The polarization conversion efficiency (minimum 87 %) and transmission values (minimum 85 %) calculated for the metalens unit cell are higher than those previously obtained over the entire 300 nm bandwidth. In addition, we propose hybrid metalens to focus the incident beam in right and left handed circular polarized states in the studied frequency range. The presented aluminum-doped zinc oxide metalens with high polarization conversion efficiency and transmission values can find a place in the applications of near-infrared nanophotonic systems.

In the present work, investigations on the second and third-order NLO properties of, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) reddye co-doped bis(8-hydroxyquinoline) Zinc (Znq₂) thin films with different concentrations were investigated. The samples have a thickness of 100 nm. They were prepared using the physical vapor deposition (PVD) method under a high vacuum. The morphological properties were studied by atomic force microscopy. The second-order nonlinear susceptibility χ⁽²⁾ after applying the corona poling technique was estimated using the comparative model of Lee, while the third-order nonlinear susceptibility χ⁽³⁾ was estimated using the comparative model of Kubodera and Kobayashi. The tested samples varied in terms of the concentration of DCM in the structure, which visibly influenced their nonlinear response. The pure DCM thin film showed a large value of the second and third-order nonlinear susceptibility, while pure Znq₂ had only the second harmonic response with a low value. In this study, we have demonstrated that doping with DCM, even with small concentrations, has also strongly enhanced the non-linearity of Znq₂. The obtained results show that such compositions can be a good alternative for optoelectronic applications.