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1.
ACS Appl Bio Mater ; 7(5): 3483-3495, 2024 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-38685505

RESUMO

The two-dimensional (2D) WSe2 nanostructure was successfully synthesized via the hydrothermal method and subjected to comprehensive characterization using various spectroscopic techniques. X-ray diffraction (XRD) analysis confirmed the formation of nanosheets with a hexagonal crystal structure having a space symmetry of P63/mmc. Scanning electron microscopy (SEM) images showed irregular and nonuniform morphology. The size of the 2D nanosheets was determined using transmission electron microscopy (TEM) providing insights intotheir physical characteristics. The optical spectrum analysis yielded a discernible band gap value of 2.1 eV, as determined by the Tauc equation. Photoluminescence (PL) spectra display an emission at a wavelength of 610 nm, showing a broad emission associated with self-trapped excitons. Under excitation at λexc = 360 nm, PL emission spectra displayed a distinct peak at 610 nm, demonstrating the ability of the nanostructure to emit vivid red light. Photometric analysis underscored the potential of this nanostructure as a prominent red-light source for diverse display applications. The optimized photodetection performance of a device showcases a photoresponsivity of approximately 1.25 × 10-3 AW-1 and a detectivity of around 5.19 × 108 Jones at a wavelength of 390 nm. Additionally, the quantum efficiency is reported to be approximately 6.99 × 10-3 at a wavelength of 635 nm. These findings highlight the capability of the device for efficient photoconversion at specified wavelengths, indicating potential applications in sensing, imaging, and optical communication. The combination of structural, morphological, and optical characterizations highlights the suitability of 2D WSe2 nanostructure for practical optoelectronic applications, particularly in display technologies.


Assuntos
Teste de Materiais , Nanoestruturas , Tamanho da Partícula , Dispositivos Eletrônicos Vestíveis , Nanoestruturas/química , Materiais Biocompatíveis/química , Materiais Biocompatíveis/síntese química
2.
3.
J Phys Chem Lett ; 14(4): 888-896, 2023 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-36662270

RESUMO

Herein, we report temperature- and field-induced magnetic states in CsPbBr3 perovskite quantum dots (PQDs) attributed to Br defects. We find that temperature-dependent structural distortion is the main source of various temperature-induced magnetic states in Br-defect host CsPbBr3 PQDs. Comprehensively examined magnetization data through Arrott plots, Langevin and Brillouin function fitting, and structural analysis reveal the presence of various oxidation states (i.e., Pb0, Pb+, Pb2+, and Pb3+) yielding different magnetic states, such as diamagnetic states above 90 K, paramagnetic states below ≈90 K, and perhaps locally ordered states between 58 and 90 K. It is realized from theoretical fits that paramagnetic ions exist (i.e., superparamagnetic behavior) due to Br defects causing Pb+ (and/or Pb3+ ions) in the diamagnetic region. We anticipate that our findings will spur future research of the development of spin-optoelectronics, such as spin light-emitting diodes, and spintronics devices based on CsPbBr3 PQDs.

4.
ACS Omega ; 7(27): 22987-22996, 2022 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-35847261

RESUMO

In this paper, we report the synthesis of zinc indium sulfide (ZnIn2S4) microspheres synthesized via a low-temperature route, and the as-synthesized material was used for photocatalytic degradation of malachite green (MG), methyl orange (MO), and Direct Red 80 (DR-80) dyes. The as-synthesized material was characterized by powder X-ray diffraction and field-emission scanning electron microscopy for studying the crystal structure and surface morphology, respectively. Fourier transform infrared spectroscopy was performed to determine the functional groups attached. UV-Visible absorption spectrometry was done for light absorbance and band gap analysis, and Mott-Schottky analysis was performed to determine the nature and flat band potential of the material. A scavenger study was performed to analyze the active species taking part in the degradation process. The reusability of the material was tested up to four cycles to check the reduction in efficiency after each cycle. A time-correlated single-photon counting study was performed to observe the average lifetime of generated excitons during photocatalysis. It was found that the as-synthesized porous sample is more efficient in degrading the cationic dye than anionic dyes, which is further explained in the article.

5.
Curr Mol Pharmacol ; 15(1): 77-107, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34551693

RESUMO

Polyphenolic phytoconstituents have been widely in use worldwide for ages and are categorised as secondary metabolites of plants. The application of polyphenols such as quercetin, resveratrol, curcumin as nutritional supplements has been researched widely. The use of polyphenols and specifically quercetin, for improving memory and mental endurance has shown significant effects among rats. Even though similar results have not been resonated among humans, but preclinical results have encouraged researchers to explore other polyphenols to study the effects as supplements among athletes. The phytopharmacological research has elucidated the use of natural polyphenols to prevent and treat various physiological and metabolic disorders owing to their free radical scavenging properties, anti-inflammatory, anti-cancer, and immunomodulatory effects. In- -spite of the tremendous pharmacological profile, one of the most dominant problem regarding the use of polyphenolic compounds is their low bioavailability. Nanonization is considered as one of the most prominent approaches among many. This article aims to review and discuss the molecular mechanisms of recently developed nanocarrier-based drug delivery systems for polyphenols and their application as drugs and supplements. Nanoformulations of natural polyphenols as bioactive agents, such as quercetin, kaempferol, fisetin, rutin, hesperetin, and naringenin epigalloccatechin- 3-gallate, genistein, ellagic acid, gallic acid, chlorogenic acid, ferulic acid, curcuminoids, and stilbenes is expected to have better efficacy. These delivery systems are expected to provide higher penetrability of polyphenols at cellular levels and exhibit a controlled release of the drugs. It is widely accepted that natural polyphenols do demonstrate significant therapeutic effects. However, the hindrances in their absorption, specificity, and bioavailability can be overcome using nanotechnology.


Assuntos
Curcumina , Polifenóis , Animais , Curcumina/farmacologia , Curcumina/uso terapêutico , Humanos , Preparações Farmacêuticas , Polifenóis/farmacologia , Polifenóis/uso terapêutico , Quercetina/farmacologia , Ratos , Resveratrol
6.
RSC Adv ; 10(57): 34651-34657, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-35514400

RESUMO

In the field of optoelectronics, all-inorganic CsPbBr3 perovskite nanocrystals (PNCs) have gained significant interest on account of their superb processability and ultra-high stability among all the counterparts. In this study, we conducted an in-depth analysis of CsPbBr3 PNCs using joint transient optical spectroscopies (time-resolved photoluminescence and ultrafast transient absorption) in a very comprehensive manner. In order to understand the in-depth analysis of excited-state kinetics, the transient absorption spectroscopy has been performed. The structure of interest of CsPbBr3 PNCs was subjected to the rates of the radiation energy of 0.10 mW (κ r/κ nr = ∼0.62) and 0.30 mW (κ r/κ nr = ∼0.64). With the rate of radiation energy 0.30 mW, it was observed that there was a significant increase in hot carrier relaxation together with high radiative recombination, resulting in a decrease in charge trappings. Herein, we demonstrate that the tuning of the rate of radiation energies helps to understand the charge-carrier kinetics of CsPbBr3 PNCs, which would thus improve the manufacturing of efficient photovoltaic devices.

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