Classification and application of metal-based nanoantioxidants in medicine and healthcare

• Nguyen Nhat Nam,
• Nguyen Khoi Song Tran,
• Tan Tai Nguyen,
• Nguyen Ngoc Trai,
• Nguyen Phuong Thuy,
• Hoang Dang Khoa Do,
• Nhu Hoa Thi Tran and
• Kieu The Loan Trinh

Beilstein J. Nanotechnol. 2024, 15, 396–415, doi:10.3762/bjnano.15.36

• natural antioxidants because of their high stability, easy storage, time effectiveness, and low cost. Also, progress in nanotechnology enables us to easily control size, morphology, surface coating, and chemical configuration, which are highly related to the antioxidant activities. The integration of

• than copper content and size. The enzyme activity of natural CAT highly depends on the three-dimensional (3D) structure of the protein. A significant decrease or even loss of CAT activity can be caused already by small changes in the protein conformation and structure. As a matter of fact, cellular

• stability during long-term storage [54][55][56]. Relying on the mechanism of chain-breaking antioxidants, nanomaterials can be synthesized to directly react with ROS after the oxidative reaction begins. Chain-breaking antioxidant nanomaterials are materials or chemical substances having a size between 0–100

Insect attachment on waxy plant surfaces: the effect of pad contamination by different waxes

• Elena V. Gorb and
• Stanislav N. Gorb

Beilstein J. Nanotechnol. 2024, 15, 385–395, doi:10.3762/bjnano.15.35

• [8] tests up to precise measurements of attachment forces with different experimental techniques, such as pulling [9] and centrifugal [10] setups. It has been demonstrated that not only the presence of wax projections on the plant cuticle surface, but also their size, distribution, and density

• centrifugal and pulling tests with some insect species bearing hairy attachment pads and mostly artificial substrates having different surface roughness. Insects showed several times higher attachment forces on both smooth and rather coarse microrough surfaces (>3 μm asperity size) compared to force values on

• projections depending on the plant species (Figure 1). Both ribbon-shaped polygonal rodlets in A. negundo (Figure 1a) and apical filamentous branches of tubules in B. oleracea (Figure 1d), although differing greatly in size (length ca. 20 μm in A. negundo according to [7][34] and 2 μm in B. oleracea according

On the mechanism of piezoresistance in nanocrystalline graphite

• Sandeep Kumar,
• Simone Dehm and
• Ralph Krupke

Beilstein J. Nanotechnol. 2024, 15, 376–384, doi:10.3762/bjnano.15.34

• and dislocations are currently under development [13][14]. This leads to the situation that the role of grain boundaries for graphene-based sensing of strain, pressure, and motion has not been explored and remains unresolved [15][16][17][18], although in CVD graphene the domain size is typically of

• the order of a few micrometers [11]. We speculated that if grain boundaries are responsible for piezoresistivity in graphene, then the gauge factor should be enhanced if one reduces the grain size to a few nanometers. Nanocrystalline graphene (NCG) is graphitic material with a crystal size of

• the crystallite size based on the full width at half maximum (FWHM) and intensity ratios of D and G peaks. Similar to our previous work [19], we use the FWHM of D and G peaks here at zero strain to calculate the crystallite size. The G peak gives a crystallite size of 2–3 nm, and the D peak

Investigating ripple pattern formation and damage profiles in Si and Ge induced by 100 keV Ar⁺ ion beam: a comparative study

• Indra Sulania,
• Harpreet Sondhi,
• Tanuj Kumar,
• Sunil Ojha,
• G R Umapathy,
• Ambuj Mishra,
• Ambuj Tripathi,
• Richa Krishna,
• Devesh Kumar Avasthi and
• Yogendra Kumar Mishra

Beilstein J. Nanotechnol. 2024, 15, 367–375, doi:10.3762/bjnano.15.33

• ripple formation on Ge is also confirmed. A. AFM images of pristine and 100 keV Ar+ ion-irradiated Si samples. (a) Pristine and irradiated samples with (b) 3 × 1017, (c) 5 × 1017, (d) 7 × 1017, and (e) 9 × 1017 ions/cm2 (all images are in 5 µm × 5 µm scan size) with corresponding wavelength distribution

• shown in B. A: AFM images of pristine and 100 keV Ar+ ion-irradiated Ge samples (a) pristine, (b) 3 × 1017, (c) 5 × 1017 (d) 7 × 1017 and (e) 9 × 1017 ions/cm2 irradiated samples (all images are in 5 µm × 5 µm scan size), B shows the corresponding wavelength distribution. TEM images of A. Si and B. Ge

Modulated critical currents of spin-transfer torque-induced resistance changes in NiCu/Cu multilayered nanowires

• Mengqi Fu,
• Roman Hartmann,
• Julian Braun,
• Sergej Andreev,
• Torsten Pietsch and
• Elke Scheer

Beilstein J. Nanotechnol. 2024, 15, 360–366, doi:10.3762/bjnano.15.32

• thickness of the NiCu and Cu layers [10][21]. To be specific, as the size of the magnetic layer (especially for soft magnets as NiCu) continues to shrink below a critical value, its magnetization is increasingly affected by thermal fluctuations, and its coercivity shrinks [22]. It has been reported that the

Controllable physicochemical properties of WO_x thin films grown under glancing angle

• Rupam Mandal,
• Aparajita Mandal,
• Alapan Dutta,
• Rengasamy Sivakumar,
• Sanjeev Kumar Srivastava and
• Tapobrata Som

Beilstein J. Nanotechnol. 2024, 15, 350–359, doi:10.3762/bjnano.15.31

• WOx films having thicknesses of 6, 10, 30, and 60 nm on p-Si substrates. It is observed that the films are granular in nature. RMS roughness (blue-green circles) and average grain size (red-blue circles) increase as the film thickness increases from 6 to 60 nm (Figure 1i). Figure 1e–h shows the AFM

• images of vacuum-annealed (at 673 K for 1 h) WOx films prepared by the same set of deposition conditions. Similar to the as-deposited ones, all annealed WOx films possess prominent granular structures and an increasing trend in grain size and RMS roughness with film thickness (Figure 1j). However, the

• -deposited and (e–h) vacuum-annealed WOx films grown at a fixed glancing angle of 87°. (i, j) Variations in RMS roughness and grain size with WOx films thickness before and after annealing, respectively. (a) Transmittance plots of the as-deposited NS-WOx films and (b) bandgap variation with film thickness

Nanomedicines against Chagas disease: a critical review

• Maria Jose Morilla,
• Kajal Ghosal and
• Eder Lilia Romero

Beilstein J. Nanotechnol. 2024, 15, 333–349, doi:10.3762/bjnano.15.30

• -II drugs with low solubility, or low or irregular bioavailability, and promoting adhesion to the gastrointestinal wall [95]. The small size of the crystals is associated with a large surface area, which increases interactions with the dissolving medium and accelerates the dissolution rate. The latest

• , nanomedicines are highly susceptible to aggregation, hygroscopicity, contamination, phase transition, amorphous-to-crystalline transitions, and degradation. It is critical to maintain batch-to-batch reproducibility (in terms of mean size, polydispersity, ζ-potential, and drug loading) not only during large

• indicative of the drug’s bioavailability. Because of their huge size, nanomedicines in the blood cannot escape from vascular confinement and are not readily able to extravasate across the endothelium. Moreover, neither their extravasation in areas of high vascular permeability, nor their accumulation in the

Comparative electron microscopy particle sizing of TiO₂ pigments: sample preparation and measurement

• Ralf Theissmann,
• Christopher Drury,
• Markus Rohe,
• Thomas Koch,
• Jochen Winkler and
• Petr Pikal

Beilstein J. Nanotechnol. 2024, 15, 317–332, doi:10.3762/bjnano.15.29

• ) pigment is a non-toxic, particulate material in widespread use and found in everyone’s daily life. The particle size of the anatase or rutile crystals are optimised to produce a pigment that provides the best possible whiteness and opacity. The average particle size is intentionally much larger than the

• for product quality assurance by three TiO2 manufacturing companies and present number-based primary particle size distributions (PSDs) obtained in a round-robin study performed on five anatase pigments fabricated by means of sulfate processes in different plants and commonly used worldwide in food

• regulatory classification for some of the samples tested. The electron microscopy results published here are supported by results from other complementary methods including surface area measurements. It is the intention of this publication to contribute to an ongoing discussion on size measurements of TiO2

Investigating structural and electronic properties of neutral zinc clusters: a G₀W₀ and G₀W₀Г₀⁽¹⁾ benchmark

• Sunila Bakhsh,
• Muhammad Khalid,
• Sameen Aslam,
• Muhammad Sohail,
• Muhammad Aamir Iqbal,
• Mujtaba Ikram and
• Kareem Morsy

Beilstein J. Nanotechnol. 2024, 15, 310–316, doi:10.3762/bjnano.15.28

• /bjnano.15.28 Abstract The structural and electronic properties of zinc clusters (Znn) for a size range of n = 2–15 are studied using density functional theory. The particle swarm optimization algorithm is employed to search the structure and to determine the ground-state structure of the neutral Zn

• ability to lose electrons quickly to oxygen makes it unsuitable as a coating material. Zinc exhibits a s2 closed-shell structure, and its dimer forms through van der Waal (vdW) forces [4]. As the cluster size increases, the properties of the clusters change significantly, and the effect of vdW forces

• properties of the clusters. Previous attempts to study the electronic properties of Zn clusters based on ∆-SCF methods tended to underestimate the ionization energies of the clusters as the size grew. State-of-the-art techniques, such as the GW method, can effectively describe the electronic properties of

Exploring the relationships between physiochemical properties of nanoparticles and cell damage to combat cancer growth using simple periodic table-based descriptors

• Joyita Roy and
• Kunal Roy

Beilstein J. Nanotechnol. 2024, 15, 297–309, doi:10.3762/bjnano.15.27

• interpretability [21][22][23][24][25]. This type of descriptors can indicate relevant features and mend the mechanism interpretation. Some properties (size, zeta potential, molecular weight, mass percentage of metal elements, and cation charge) are investigated to have a better understanding of the structure of

• descriptors were calculated without any expert intervention and are independent of size variations. Splitting of the data sets Splitting of the datasets into training sets and test sets is essential for developing statistically robust nano-QSPR models. Each of the datasets, that is, the zeta potential dataset

• *). Here, h* is the warning leverage in the Williams plot or applicability domain; compounds lying above this critical value are considered as outliers. The critical leverage h* is calculated as h* = 3p/n, where p stands for the number of modeled variables plus one and n stands for the data size of the

Determining by Raman spectroscopy the average thickness and N-layer-specific surface coverages of MoS₂ thin films with domains much smaller than the laser spot size

• Felipe Wasem Klein,
• Jean-Roch Huntzinger,
• Vincent Astié,
• Damien Voiry,
• Romain Parret,
• Houssine Makhlouf,
• Sandrine Juillaguet,
• Jean-Manuel Decams,
• Sylvie Contreras,
• Périne Landois,
• Ahmed-Azmi Zahab,
• Jean-Louis Sauvajol and
• Matthieu Paillet

Beilstein J. Nanotechnol. 2024, 15, 279–296, doi:10.3762/bjnano.15.26

• injection pulsed-pressure chemical vapor deposition (DLI-PP-CVD). Such samples are constituted of nanoflakes (with a lateral size of typically 50 nm, i.e., well below the laser spot size), with possibly a distribution of thicknesses and twist angles between stacked layers. As an essential preliminary, we

• . However, atomic force microscopy revealed that they are constituted of nanoflakes (with a lateral size of typically 50 nm) with possibly a distribution of thicknesses. Furthermore, depending on the synthesis conditions, the MoS2 surface coverage can be incomplete, and the thin film average thickness can

• vary. These samples thus have characteristics, especially thickness inhomogeneities smaller than the laser spot size, that differ from the ones used to establish Raman spectroscopy-based MoS2 layer counting methods [26][28][29][30][31][32][33]. In this context, the primary purpose of this work is to

Ultrasensitive and ultrastretchable metal crack strain sensor based on helical polydimethylsiloxane

• Shangbi Chen,
• Dewen Liu,
• Weiwei Chen,
• Huajiang Chen,
• Jiawei Li and
• Jinfang Wang

Beilstein J. Nanotechnol. 2024, 15, 270–278, doi:10.3762/bjnano.15.25

• (with an error range of approximately 5%) to 116.52 Ω. However, during the subsequent stretching period of 160–220 cycles, the resistance remains relatively stable, ranging from 116.52 to 117.49 Ω. Based on these observations, it is inferred that quantity and size of the cracks in the helical samples

Vinorelbine-loaded multifunctional magnetic nanoparticles as anticancer drug delivery systems: synthesis, characterization, and in vitro release study

• Zeynep Özcan and
• Afife Binnaz Hazar Yoruç

Beilstein J. Nanotechnol. 2024, 15, 256–269, doi:10.3762/bjnano.15.24

• morphology and a size of 18 nm. After coating with PDA at different ratios, the size reaches up to 28, 61, and 225 nm. Another point is that PEGylation has been applied using SH-PEG polymer to enhance biocompatibility. Notably, our study demonstrates a significantly higher drug loading efficiency of 98

• a solvothermal technique in a stainless steel reactor at 200 °C for 6 h. According to the results of FE-SEM and STEM examinations, the Fe3O4 NPs are spherical, as depicted in Figure 1a–c. When examining the STEM size distribution, it was observed that Fe3O4 NPs were efficiently synthesized with an

• average size of 18 nm. The Fe3O4 NPs consist of 99.9% magnetite and have a cubic reverse spinel structure. Magnetite exhibits a spinel crystal structure resulting in a face-centered cubic arrangement in which oxygen atoms are positioned opposite the other constituent atoms. The Fe3O4 NP (311) reflection

Design, fabrication, and characterization of kinetic-inductive force sensors for scanning probe applications

• August K. Roos,
• Ermes Scarano,
• Elisabet K. Arvidsson,
• Erik Holmgren and
• David B. Haviland

Beilstein J. Nanotechnol. 2024, 15, 242–255, doi:10.3762/bjnano.15.23

• L and capacitance C. The relatively small size available from the cantilever dimensions motivates the use of kinetic inductance to achieve a compact lumped-element inductor with negligible stray capacitance. Mattis–Bardeen theory [30] relates the kinetic inductance of a film with thickness t much

• with 600 nm low-stress (<100 MPa) Si-N films. The sensor chips are 1.6 mm by 3.4 mm, about the size of a standard AFM cantilever chip. The steps are as follows: (a) Superconducting film. We first deposit a 15 nm thick thin film of superconducting Nb60Ti40N by reactive co-sputtering from separate

• different radii to achieve a total tip height in the range of 1–2 μm. This conical structure gives added rigidity to lateral forces while scanning. We form a sharp tip at the apex of the cone by exposing a circular area with a diameter of 10 nm, which is smaller than the nominal electron-beam spot size, and

Quantitative wear evaluation of tips based on sharp structures

• Ke Xu and
• Houwen Leng

Beilstein J. Nanotechnol. 2024, 15, 230–241, doi:10.3762/bjnano.15.22

• studies. Another approach involves blind reconstruction based on AFM images. Bellotti et al. [15] introduced a uniquely shaped nanoparticle as a tip characterizer. They conducted tip shape analysis using AFM images centered on a single nanoparticle on a flat substrate to investigate the critical size of

• . Assuming that the image size is M × N and the initial probe template size is m × n, the center point of the subgraph T must correspond to the local maximum within the subgraph T. In other words, the value of the center of T should be greater than or equal to the value of its adjacent points in the subgraph

Multiscale modelling of biomolecular corona formation on metallic surfaces

• Parinaz Mosaddeghi Amini,
• Ian Rouse,
• Julia Subbotina and
• Vladimir Lobaskin

Beilstein J. Nanotechnol. 2024, 15, 215–229, doi:10.3762/bjnano.15.21

• orientation of each individual protein, a primary coarse-graining step was performed. In this part, we use the UA model to predict the protein–NP binding energies. This model takes into account various factors, such as the material’s chemical composition, size, shape, surface roughness, charge

• , all proteins underwent a 50 ns equilibration in water using NVT and NPT ensembles. The UA computations were conducted using nine different Al NPs with varying radii, namely 2, 5, 10, 20, 30, 40, 50, 80, and 100 nm, to investigate the influence of size and curvature on the adsorption energies. The

• results and detailed information on the calculation can be found in Supporting Information File 1, Figure S2 and Figure S3, which illustrate the variations in adsorption energies as a function of NP size. Within the range of 2–20 nm the binding energies of ALAC, BLAC, BC, and BSA show an initial increase

Ion beam processing of DNA origami nanostructures

• Leo Sala,
• Agnes Zerolová,
• Violaine Vizcaino,
• Alain Mery,
• Alicja Domaracka,
• Hermann Rothard,
• Philippe Boduch,
• Dominik Pinkas and
• Jaroslav Kocišek

Beilstein J. Nanotechnol. 2024, 15, 207–214, doi:10.3762/bjnano.15.20

• the trenches [21]. Even in these elevated areas very close to the line edge, the trimmed DNA origami nanostructures merely follow the contours. For the FIB-SEM setup used, this was the narrowest beam generated. Reducing the beam size would allow for even more precise trimming of the nanostructures for

Exploring disorder correlations in superconducting systems: spectroscopic insights and matrix element effects

• Vyacheslav D. Neverov,
• Alexander E. Lukyanov,
• Andrey V. Krasavin,
• Alexei Vagov,
• Boris G. Lvov and
• Mihail D. Croitoru

Beilstein J. Nanotechnol. 2024, 15, 199–206, doi:10.3762/bjnano.15.19

• take N = 50, which our calculations show is sufficiently large to mitigate finite-size effects. BdG equations (Equation 2) are solved together with the self-consistency conditions (Equation 3) in the usual way until the order parameter and the Hartree potential reach a predefined accuracy threshold [63

• potential), α = 1 (modest correlation with a finite correlation length), and α = 2 (strong correlation with the correlation length reaching the sample size). The solutions to the Bogoliubov–de Gennes (BdG) equations, encompassing an examination of their statistical attributes, spatial characteristics of the

Graphene removal by water-assisted focused electron-beam-induced etching – unveiling the dose and dwell time impact on the etch profile and topographical changes in SiO₂ substrates

• Aleksandra Szkudlarek,
• Jan M. Michalik,
• Inés Serrano-Esparza,
• Zdeněk Nováček,
• Veronika Novotná,
• Piotr Ozga,
• Czesław Kapusta and
• José María De Teresa

Beilstein J. Nanotechnol. 2024, 15, 190–198, doi:10.3762/bjnano.15.18

• is dependent on the precursor dynamics (adsorption/desorption rate, diffusion), electron beam (lateral size, electron flux, energy), and scanning parameters (dwell time, refresh time, scanning strategy) [22]. Additionally, residual hydrocarbons inside the scanning electron microscope chamber manifest

• be optimized to prevent unnecessary defects and reduce the detrimental impact on the underlying substrate. The optical microscope image of the graphene flake before the patterning process is shown in Figure 2A. The size of the etched lines, estimated based on SEM measurements, is usually smaller than

• estimated beam size equal to 10 nm (FWHM), are summarized in Table 1. The results of Raman spectroscopy measurements are shown in Figure 2C and Figure 2D. This technique is not only sensitive to the number of graphitic layers in graphene but, more importantly, also to the number of defects, which can be

Nanocarrier systems loaded with IR780, iron oxide nanoparticles and chlorambucil for cancer theragnostics

• Phuong-Thao Dang-Luong,
• Hong-Phuc Nguyen,
• Loc Le-Tuan,
• Xuan-Thang Cao,
• Vy Tran-Anh and
• Hieu Vu Quang

Beilstein J. Nanotechnol. 2024, 15, 180–189, doi:10.3762/bjnano.15.17

• alcohol)-based nanoparticles (NPs) using the single emulsion technique. Then the NPs were coated with F127 and F127-folate by simple incubation for five days. The nanoparticles have the hydrodynamic size of approx. 250 nm with negative charge. Similar to chlorambucil and IR780, iron oxide loadings were

• cells. Hydrodynamic size and zeta potential Dynamic light scattering (DLS) and zeta potential spectra were obtained for three replicates on a nanoPartical Horiba SZ-100 (Japan) with the scattering angle of 90° to determine the size distribution and stability of the nanoparticles. The DLS measurements

• assay, and the absorbance was read at 562 nm (Biotek ELX800, Agilent, USA). Results The morphology, size, and zeta potential of the particles The hydrodynamic size of the three types of NPs (Figure 1A) ranged from 245 ± 11 nm to 246 ± 2 nm with the polydispersity index (PDI) smaller than 0.12, which

Modification of graphene oxide and its effect on properties of natural rubber/graphene oxide nanocomposites

• Nghiem Thi Thuong,
• Le Dinh Quang,
• Vu Quoc Cuong,
• Cao Hong Ha,
• Nguyen Ba Lam and
• Seiichi Kawahara

Beilstein J. Nanotechnol. 2024, 15, 168–179, doi:10.3762/bjnano.15.16

• efficiently attached to GO, and the attachment was more efficient in basic conditions rather than acidic conditions. Scanning electron microscopy images Figure 8 shows SEM images for GO-VTES(a) and GO-VTES(b). As can be seen, silica was produced with a size of approx. 50 nm for GO-VTES(a) and GO-VTES(b). It

Ferromagnetic resonance spectra of linear magnetosome chains

• Elizaveta M. Gubanova and
• Nikolai A. Usov

Beilstein J. Nanotechnol. 2024, 15, 157–167, doi:10.3762/bjnano.15.15

• nanoparticles; numerical simulation; Introduction Magnetotactic bacteria are living organisms that grow within themselves magnetite nanoparticles called magnetosomes [1][2][3][4]. In contrast to chemically synthesized magnetite nanoparticles [5][6], magnetosomes have a perfect crystal structure, a narrow size

CdSe/ZnS quantum dots as a booster in the active layer of distributed ternary organic photovoltaics

• Gabriela Lewińska,
• Piotr Jeleń,
• Zofia Kucia,
• Maciej Sitarz,
• Łukasz Walczak,
• Bartłomiej Szafraniak,
• Jerzy Sanetra and
• Konstanty W. Marszalek

Beilstein J. Nanotechnol. 2024, 15, 144–156, doi:10.3762/bjnano.15.14

• . The emission wavelength is determined by the crystal size and structure; crystals of the same chemistry can have emission maxima spanning a wide range. As the size of the dots decreases, both their optical absorption and emission shift to higher energies [41]. Because hydrophilic QDs are coated with

• impact on the layer under consideration, a weight ratio of 1:0.5:0.5 was chosen (donor:acceptor:QDs). The quantum dot designations used in the paper are summarized in Table 1. The numbers next to the abbreviation QD refer to the maximum luminescence suggested by the manufacturer. The size of the

• nanoparticles, including the size of the shell (0.6 nm), and the core size declared by the manufacturer are included in Table 1. UV–vis spectroscopy was conducted with an Avantes Sensline Ava-Spec ULS-RS-TEC fiber-optic spectrophotometer and an Avantes AvaLight DH-S-BAL-Hal lamp. The absorption and luminescence

In situ optical sub-wavelength thickness control of porous anodic aluminum oxide

• Aleksandrs Dutovs,
• Raimonds Popļausks,
• Oskars Putāns,
• Vladislavs Perkanuks,
• Aušrinė Jurkevičiūtė,
• Tomas Tamulevičius,
• Uldis Malinovskis,
• Iryna Olyshevets,
• Donats Erts and
• Juris Prikulis

Beilstein J. Nanotechnol. 2024, 15, 126–133, doi:10.3762/bjnano.15.12

• the central 5 × 5 mm2 part of the sample surface, in a grid of 20 × 20 with 254 μm distance between each position. The spot size for SE mapping was 365 μm × 470 μm at 75° angle of incidence. The fitting of the optical model to the experimental data was done in Spectroscopic Ellipsometry Analyzer

Assessing phytotoxicity and tolerance levels of ZnO nanoparticles on Raphanus sativus: implications for widespread adoptions

• Pathirannahalage Sahan Samuditha,
• Nadeesh Madusanka Adassooriya and
• Nazeera Salim

Beilstein J. Nanotechnol. 2024, 15, 115–125, doi:10.3762/bjnano.15.11

• to the reflection from (100), (002), (101), (102), (110), (103), (200), (112), and (201) crystal planes of ZnO NPs, respectively. The average size reported in the particle size analyzer for ZnO NPs was 122.4 nm, as shown in Figure 1b, with a polydispersity index of 0.332. The FTIR spectrum of ZnO NPs

• ZnO NPs characterization The PXRD technique provides important insights into the chemical composition, physical characteristics of the material and crystallographic structure, and crystalline particle size based on the scattered X-ray beam intensity [20][21]. The PXRD pattern (Figure 1a) of

• absorption peak below 400 nm due to the nanometric size effect of the synthesized ZnO and characteristic hexagonal ZnO NPs [32]. A broad band at 362 nm in the UV–vis spectrum was reported, indicating the formation of ZnO NPs, and it could be due to an electron transfer from the valence to the conduction band