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The nanosecond Nd:YAG pulsed laser ablation in liquid (PLAL) technique was used to successfully synthesize hybrid Fe3O4-Au nanoparticles (NPs). The synthesized nanoparticles were investigated using different techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-VIS spectroscopy, field emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), UV-VIS spectroscopy, and photoluminescent spectroscopy (PL). Then the NP concentration in the bacterial pathogen was investigated. The FTIR and XRD data confirmed the successful synthesis of Fe3O4 NPs doped with Au. The morphology of hybrid Fe3O4-Au NPs was observed to be agglomerated into semispherical nanostructure particles. The absorption and PL properties of the nanoparticles were found to vary with doping concentrations. Additionally, bacterial activity was effectively inhibited by the hybrid NPs, which were found to be more effective against gram-negative and gram-positive strains, with a highly inhibited zone against Acinetobacter baumannii. Also, the inhibition zone increased with increasing doping concentrations of NPs. [ABSTRACT FROM AUTHOR]

High electric fields affect the diffusion dynamics of atoms on a metal surface, causing biased surface diffusion that possibly leads to the growth of intensively field emitting protrusions and consequent vacuum breakdown (VBD). The scientific understanding of this process, as well as other fundamental VBD initiation mechanisms, is far from complete. Here we investigate the exact atomic behaviour of metal surfaces exposed to extremely high electric fields using density functional theory (DFT). Previous theories describe the field-surface dynamics in terms of the effective dipole moments and polarizability of surface atoms, disregarding higher-order (hyperpolarizability) terms. The validity of this approximation has been evaluated only for electric fields up to 3 GV/m, due to computational limitations of the plane-wave DFT basis used in previous works. In this work, we test the validity of this approximation for a much wider field range, relevant for VBD and field emission (FE), using Cu nanoparticles as our test structures. We find that although such high fields can change the entire structure of Cu nanoparticles, their energetics are described very precisely by the permanent dipole moment and polarizability terms. Thus, we show that neglecting the hyperpolarizability terms is valid even for field values that exceeds the range that is relevant for intense FE and VBD. This work lays a solid foundation for further developing atomic-level simulation models for electric field-induced surface diffusion on metal surfaces and its effects on protrusion growth and VBD initiation. [ABSTRACT FROM AUTHOR]

In this study, a novel core/shell nanocomposite structure (h-BN@Gd2O3 NCs) was created for the first time by combining hexagonal boron nitride (h-BN) with doped gadolinium oxide (Gd2O3) using different laser pulse numbers, i.e., 150, 338, and 772 pulses. We employed various analytical techniques, including mapping analysis, FE-SEM, EDS, HRTEM, SAED, XRD, zeta potential analysis, DLS, FTIR, Raman spectroscopy, and PL measurements, to characterize the synthesized h-BN, c-Gd2O3, and h-BN@Gd2O3 NCs (338 pulses). XRD results indicated hexagonal and cubic crystal structures for BN and Gd2O3, respectively, while EDS confirmed their chemical composition and elemental mapping. Chemical bonds between B–N–Gd, B–N–O, and Gd–O bands at 412, 455, 474, and 520 cm−1 were identified by FTIR analysis. The antimicrobial and anticancer activities of these NCs using agar well diffusion and MTT assays. They exhibited potent antibacterial properties against both Gram-positive and Gram-negative pathogens. Furthermore, NCs have reduced the proliferation of cancerous cells, i.e., human colon adenocarcinoma cells (HT-29) and human breast cancer cells (MCF-7), while not affecting the proliferation of the normal breast cell line (MCF-10). The anticancer efficacy of NCs was validated by the AO/EtBr assay, which confirmed apoptotic cell death. Blood compatibility on human erythrocytes was also confirmed by hemolytic and in vitro toxicity assessments. The compiled results of the study proposed these nanoparticles could be used as a promising drug delivery system and potentially in healthcare applications. [ABSTRACT FROM AUTHOR]

Pulsed laser ablation in liquid technique was used to prepare pure and doped CdO NPs with varied Ag concentrations. The prepared nanoparticles were characterized using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV–vis spectroscopy, Field-emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS), and atomic force microscopy. The FTIR and XRD data confirm the construction of CdO NPs doped with Ag. The morphology of pure CdO NPs was found to be agglomerated in bundles that resemble tangled nanowires, which changed to nanorods and interconnecting web architectures as Ag concentration increased. The absorption of these nanoparticles varied with Ag doping concentrations. Additionally, the gas-sensing properties of the pure and doped CdO sensor were investigated. The gas-sensing response of the composite nanoparticles' sensor to NO2 was 46, which was 1.8 times larger than the response of the pure CdO NP sensor (24.9). Thus, oxidizing gas (NO2) was found to be less sensitive to Ag-doped CdO nanocomposite sensors than reducing gas (H2S). [ABSTRACT FROM AUTHOR]

Colloidal In2O3NPs-MWCNTs heterostructure (NPs) were successfully synthesized by a facile one-step Q-switched Nd: YAG laser ablation of indium target in CNTs suspension at room temperature. Raman spectroscopy and optical absorption analysis of the prepared samples confirmed the formation of In2O3NPs-MWCNTs heterostructure. Transmission electron microscope (TEM) investigation of In2O3-CNTs structure and pure In2O3 nanoparticles revealed the formation of spherical nanoparticles with average size of 66 nm and 19 nm, respectively. The heterojunction photodetectors were fabricated by drop casting of colloidal In2O3NPs-MWCNTs NPs onto a single crystal silicon wafer. I–V characteristics of the In2O3NPs/Si and In2O3NPs-MWCNTs/Si heterojunctions under both dark and light conditions revealed rectifying properties and good photo-response. The built-in voltage was determined from the C–V measurements which revealed an abrupt junction and their values of 1.05 V and 0.59 V for In2O3NPs-MWCNTs/Si and In2O3NPs/Si, respectively. In2O3NPs-MWCNTs/Si photodetector demonstrated the highest responsivity and quantum efficiency of 1.3 A/W and 3.5 × 102% at 450 nm, respectively. This In2O3-MWCNTs heterostructure-based photodetector with improved performance may open the door to effective Vis–NIR photodetection applications.Graphical Abstract: Colloidal In2O3NPs-MWCNTs heterostructure (NPs) were successfully synthesized by a facile one-step Q-switched Nd: YAG laser ablation of indium target in CNTs suspension at room temperature. Raman spectroscopy and optical absorption analysis of the prepared samples confirmed the formation of In2O3NPs-MWCNTs heterostructure. Transmission electron microscope (TEM) investigation of In2O3-CNTs structure and pure In2O3 nanoparticles revealed the formation of spherical nanoparticles with average size of 66 nm and 19 nm, respectively. The heterojunction photodetectors were fabricated by drop casting of colloidal In2O3NPs-MWCNTs NPs onto a single crystal silicon wafer. I–V characteristics of the In2O3NPs/Si and In2O3NPs-MWCNTs/Si heterojunctions under both dark and light conditions revealed rectifying properties and good photo-response. The built-in voltage was determined from the C–V measurements which revealed an abrupt junction and their values of 1.05 V and 0.59 V for In2O3NPs-MWCNTs/Si and In2O3NPs/Si, respectively. In2O3NPs-MWCNTs/Si photodetector demonstrated the highest responsivity and quantum efficiency of 1.3 A/W and 3.5 × 102% at 450 nm, respectively. This In2O3-MWCNTs heterostructure-based photodetector with improved performance may open the door to effective Vis–NIR photodetection applications. [ABSTRACT FROM AUTHOR]