Recent advances in nanoarchitectures of monocrystalline coordination polymers through confined assembly

• Lingling Xia,
• Qinyue Wang and
• Ming Hu

Beilstein J. Nanotechnol. 2022, 13, 763–777, doi:10.3762/bjnano.13.67

• packing than spherical particles. In addition, their porous structure can accommodate guest molecules, which can further alternate the properties of the whole assembly. These features give the assembled superstructures more freedom to change their properties, such as the photonic bandgap, which has been

Hierarchical Bi₂WO₆/TiO₂-nanotube composites derived from natural cellulose for visible-light photocatalytic treatment of pollutants

• Zehao Lin,
• Zhan Yang and
• Jianguo Huang

Beilstein J. Nanotechnol. 2022, 13, 745–762, doi:10.3762/bjnano.13.66

• ][8]. However, the wide bandgap of TiO2 inhibits the absorption of light in the visible region and the rapid recombination of photogenerated electron−hole pairs restrains its photocatalytic activity. It has been verified that constructing TiO2-based heterostructured composites by using visible-light

• (Supporting Information File 1, Figure S7), the cellulose-derived 70%−Bi2WO6/TiO2-NT nanocomposite possesses wider absorption edge in the UV–vis DRS, corresponding narrower bandgap, and weaker PL intensity in the PL spectra, suggesting stronger response to visible light and more efficient separation of the

Direct measurement of surface photovoltage by AC bias Kelvin probe force microscopy

• Masato Miyazaki,
• Yasuhiro Sugawara and
• Yan Jun Li

Beilstein J. Nanotechnol. 2022, 13, 712–720, doi:10.3762/bjnano.13.63

• [41][42][43][44]. Rutile TiO2 has a bandgap of 3.0 eV [45] and shows the SPV under UV illumination [46][47][48]. A clean rutile TiO2(110) surface (Crystal Base) was prepared by several cycles of Ar+ sputtering (1 keV, 1 × 10−6 Torr, 15 min) and annealing (993 K, less than 2 × 10−10 Torr, 30 min

Sodium doping in brookite TiO₂ enhances its photocatalytic activity

• Boxiang Zhuang,
• Honglong Shi,
• Honglei Zhang and
• Zeqian Zhang

Beilstein J. Nanotechnol. 2022, 13, 599–609, doi:10.3762/bjnano.13.52

• mixes with anatase or rutile [14][15]. (2) The bandgap Eg is important for the photocatalytic behavior of brookite TiO2; however, the precise value of Eg is still unknown. The measured Eg value varies from 1.9 to 3.4 eV [16][17], and the theoretical value ranges from 1.8 to 3.3 eV [18]. (3) The

• , the reaction rate constant in this report was about three times higher than that of the quasi-spherical brookite TiO2 (k = 0.0206) [22]. The excellent photocatalytic activity can be correlated with the crystal structure, micromorphology, and chemical composition [23][24][25]. The bandgap is useful to

• understand the photocatalytic behavior of a given material. The bandgap values were determined from the diffuse reflectance spectra using the Tauc plot method [26]: where A in Equation 1 is a proportional constant, α is the absorption coefficient, and n depends on the type of electron transition. The bandgap

Revealing local structural properties of an atomically thin MoSe₂ surface using optical microscopy

• Lin Pan,
• Peng Miao,
• Anke Horneber,
• Alfred J. Meixner,
• Pierre-Michel Adam and
• Dai Zhang

Beilstein J. Nanotechnol. 2022, 13, 572–581, doi:10.3762/bjnano.13.49

• fascinating optical and electronic properties [1]. In particular, the optical absorption, direct bandgap, and broken inversion symmetry of 2D transition-metal dichalcogenide (2D-TMDC) monolayers make these materials promising candidates for light-emitting diodes, photodetectors, field-effect transistors

• all Raman peaks. This is attributed to the fact that these vibrational modes possess large dipoles leading to a strong dipole–dipole interaction with the underlying h-BN. The MoSe2 monolayer used in our work is a direct-bandgap semiconductor and has a polar covalent bond (Mo–Se). The Raman peaks of

• region (bilayer) and the center position (monolayer) of CuPc on MoSe2 flake. The photoluminescence peak is due to the direct bandgap emission in the MoSe2 monolayer. (c) A sketch of the energy level diagram at the interface between CuPc molecule and 2H MoSe2 monolayer. The ground-state charge transfer

Zinc oxide nanostructures for fluorescence and Raman signal enhancement: a review

• Ioana Marica,
• Fran Nekvapil,
• Maria Ștefan,
• Cosmin Farcău and
• Alexandra Falamaș

Beilstein J. Nanotechnol. 2022, 13, 472–490, doi:10.3762/bjnano.13.40

• their wide bandgap energy (3.3–3.7 eV), strong luminescence [4][5], antibacterial properties, and UV-protection properties. Additionally, ZnO nanomaterials can be designed into various morphologies, such as nanoparticles, nanoneedles, nanorods, nanocages, nanocombs, and nanoflowers [5][6][7][8]. Hybrid

• shapes used for SERS applications, as well as spherical ZnO nanoparticles [8] are given in Figure 1. Combination of ZnO nanostructures with noble metals The use of inexpensive semiconducting materials, such as wide-bandgap ZnO or TiO2, for SPR-based substrates has gained increased attention in recent

• decrease of the bandgap of ZnO. All of these are contributing to the SERS enhancement. A SERS substrate enhancement factor of 5.4 × 107 and an analytical enhancement factor of 1.3 × 1010 were obtained with Ag–ZnO heterostructures on glass substrates for the detection of methylene orange molecules. These

Selected properties of Al_xZn_yO thin films prepared by reactive pulsed magnetron sputtering using a two-element Zn/Al target

• Witold Posadowski,
• Artur Wiatrowski,
• Jarosław Domaradzki and
• Michał Mazur

Beilstein J. Nanotechnol. 2022, 13, 344–354, doi:10.3762/bjnano.13.29

• shorter wavelengths, from about 370 to 342 nm (Figure 5b). The measured light transmission characteristics were further used to determine the thickness and the optical bandgap energy of the prepared films. For the analysis, the reverse synthesis method was applied. The analysis allowed for simultaneous

• distance of about 70 mm from the target axis. Therefore, one can conclude that the area for the substrate placement with favorable conditions for the preparation of transparent and well-conductive films is located outside the radial boundary of the target. The analysis of the optical bandgap energy (Eg) as

• a function of X for the films deposited at the front side of the substrate is presented in Figure 8. As one can see, with increasing X, the optical bandgap increased from about 3.10 to about 3.55 eV. Such a large change suggests a relatively large change in the material composition, which will be

The effect of metal surface nanomorphology on the output performance of a TENG

• Yiru Wang,
• Xin Zhao,
• Yang Liu and
• Wenjun Zhou

Beilstein J. Nanotechnol. 2022, 13, 298–312, doi:10.3762/bjnano.13.25

• –semiconductor and semiconductor–metal contact pairs [14][15]. A semiconductor–metal contact can be described by the band diagram shown in Figure 1. The frictional electrical properties of materials depend on their work functions and Fermi levels [16][17]. The intermediate state in the bandgap can reduce the

Investigation of a memory effect in a Au/(Ti–Cu)Ox-gradient thin film/TiAlV structure

• Damian Wojcieszak,
• Jarosław Domaradzki,
• Michał Mazur,
• Tomasz Kotwica and
• Danuta Kaczmarek

Beilstein J. Nanotechnol. 2022, 13, 265–273, doi:10.3762/bjnano.13.21

• resistive switching behavior. Results of optical, X-ray, and ultraviolet photoelectron spectroscopy measurements allowed us to elaborate the scheme of the bandgap alignment of the prepared thin films with respect to the Au and TiAlV electrical contacts. Detailed structure and elemental profile

• and reaches 40% on average. Visible maxima and minima result from multiple interferences of the light reflected from interfaces between air and thin film and thin film and SiO2 substrate. From the optical spectra, an optical bandgap width of about 2.8 eV was determined for the allowed indirect

• spectrum as marked in Figure 7a; it is 1.20 eV below the Fermi level (EF). Taking into consideration the bandgap energy of the thin films equal to 2.80 eV, the thin film surface exhibits p-type conduction. The electron affinity (χ) of the thin film surface was equal to 2.41 eV and was calculated based on

Engineered titania nanomaterials in advanced clinical applications

• Padmavati Sahare,
• Paulina Govea Alvarez,
• Juan Manual Sanchez Yanez,
• Gabriel Luna-Bárcenas,
• Samik Chakraborty,
• Sujay Paul and
• Miriam Estevez

Beilstein J. Nanotechnol. 2022, 13, 201–218, doi:10.3762/bjnano.13.15

• therapy. The cytotoxic properties of TiO2 are related to differences in phase composition. The anatase phase has a higher toxicity due to its wider bandgap and effectiveness in the generation of ROS [27]. Lower amounts of ROS, which operate as redox signaling messengers, are essential for optimal

• direct route for both bandgap engineering and photoactivity enhancement. One strategy employed was high-pressure and high-temperature hydrogenation, resulting in reduced “black TiO2” (B-TiO2−x) nps with a crystalline center and a disordered surface that absorbs light in the visible range. Chen et al

Theoretical understanding of electronic and mechanical properties of 1T′ transition metal dichalcogenide crystals

• Seyedeh Alieh Kazemi,
• Sadegh Imani Yengejeh,
• Vei Wang,
• William Wen and
• Yun Wang

Beilstein J. Nanotechnol. 2022, 13, 160–171, doi:10.3762/bjnano.13.11

• well-known differences between these two phases is their electronic properties. Using MoS2 as an example, its 1T′ and 2H polytypes are discussed by presenting their DOS and band structure, as illustrated in Figure 5a. There is a bandgap in the 2H polytype, which indicates that it is a semiconductor. On

A comprehensive review on electrospun nanohybrid membranes for wastewater treatment

• Senuri Kumarage,
• Imalka Munaweera and
• Nilwala Kottegoda

Beilstein J. Nanotechnol. 2022, 13, 137–159, doi:10.3762/bjnano.13.10

A photonic crystal material for the online detection of nonpolar hydrocarbon vapors

• Evgenii S. Bolshakov,
• Aleksander V. Ivanov,
• Andrei A. Kozlov,
• Anton S. Aksenov,
• Elena V. Isanbaeva,
• Sergei E. Kushnir,
• Aleksei D. Yapryntsev,
• Aleksander E. Baranchikov and
• Yury A. Zolotov

Beilstein J. Nanotechnol. 2022, 13, 127–136, doi:10.3762/bjnano.13.9

• qualitative detection of saturated vapors of volatile organic compounds due to configuration changes of the photonic bandgap, recorded by diffuse reflectance spectroscopy. The exposure of the sensor to aromatic (benzene, toluene and p-xylene) and aliphatic (n-pentane, n-heptane, n-octane and n-decane

• removed, then it is an inverse opal structure [11][12][13]. A photonic bandgap (PBG) appears in colloidal crystals due to the periodic modulation of the refractive index. At the bandgap, selective reflection of light is observed, which is connected to a low photon density of states within the materials

• [14]. Most of the configuration changes of the photonic bandgap in opal and inverse opal structures occur due to swelling or compression of the polymer matrix or gel. To date, four main methods for the modification of photonic crystals are used for the creation of stimuli-responsive materials: (a

Tin dioxide nanomaterial-based photocatalysts for nitrogen oxide oxidation: a review

• Viet Van Pham,
• Hong-Huy Tran,
• Thao Kim Truong and
• Thi Minh Cao

Beilstein J. Nanotechnol. 2022, 13, 96–113, doi:10.3762/bjnano.13.7

• morphology. Recent studies have been focused on the modification of properties of SnO2 to increase the photocatalytic efficiency of SnO2, including bandgap engineering, defect regulation, surface engineering, heterojunction construction, and using co-catalysts, which will be thoroughly highlighted in this

• morphology [25][26][27][28][29][30]. However, pure SnO2 suffers from some inherent drawbacks that limit its practical applications. With a wide bandgap (3.5–3.7 eV) [31][32], SnO2 can only be excited by UV irradiation. As a typical oxidation photocatalyst with the CB edge energy level, which is not conducive

• depends on many factors, including the structure and energy band, surface and defect states, morphology, etc. For that reason, recent studies are being focused on the modification of properties of SnO2 to upgrade the photocatalytic efficiency of SnO2, including bandgap engineering, defect regulation

Chemical vapor deposition of germanium-rich CrGe_x nanowires

• Vladislav Dřínek,
• Stanislav Tiagulskyi,
• Roman Yatskiv,
• Jan Grym,
• Radek Fajgar,
• Věra Jandová,
• Martin Koštejn and
• Jaroslav Kupčík

Beilstein J. Nanotechnol. 2021, 12, 1365–1371, doi:10.3762/bjnano.12.100

• undoped Ge nanowires or intrinsic bulk germanium [21]. One of the possible explanations is that Cr can form deep levels within the Ge bandgap [22]. These levels act as recombination centers and increase the resistivity. However, a precise determination of the influence of Cr incorporation on the

First-principles study of the structural, optoelectronic and thermophysical properties of the π-SnSe for thermoelectric applications

• Muhammad Atif Sattar,
• Najwa Al Bouzieh,
• Maamar Benkraouda and
• Noureddine Amrane

Beilstein J. Nanotechnol. 2021, 12, 1101–1114, doi:10.3762/bjnano.12.82

• (DFT). Our DFT calculations reveal that π-SnSe features an optical bandgap of 1.41 eV and has an exceptionally large lattice constant (12.2 Å, P213). We report several thermodynamic, optical, and thermoelectric properties of this π-SnSe phase for the first time. Our finding shows that the π-SnSe alloy

• the next generation of electronic and photonic systems [35][36]. The orthorhombic α-SnSe, an indirect bandgap (0.9 eV) semiconductor, has been an immense research topic in the TE field since the highest ZT value of ≈2.6 at 923 K was reported in the p-type single crystal along the b axis [1]. The n

• coordinates along with the volume of the π-SnSe system are allowed to fully relax. We used the PBEsol exchange-correlation functional [52] and the PAW projections were carried out within the reciprocal space. For more accurate electronic structures (e.g., bandgap), we used the computationally inexpensive

Assessment of the optical and electrical properties of light-emitting diodes containing carbon-based nanostructures and plasmonic nanoparticles: a review

• Keshav Nagpal,
• Erwan Rauwel,
• Frédérique Ducroquet and
• Protima Rauwel

Beilstein J. Nanotechnol. 2021, 12, 1078–1092, doi:10.3762/bjnano.12.80

• semiconductors and emit from the UV to the red region of the visible spectrum via bandgap tuning (i.e., on alloying with In and Al [5][6][7]). Similarly, other active materials for quantum dot light-emitting diodes (QLED), such as the II–VI semiconductor family include ZnO, CdSe, CdS, CdTe, ZnSe, ZnS, ZnTe, and

• their core–shell structures with Zn-based compounds possessing higher bandgaps than Cd-based compounds [8][9][10][11][12]. The wide bandgap of Zn-based compounds has provided an opportunity to produce blue-emitting ‘all ZnO’-based LED, following the successful fabrication of p-type ZnO [13]. Organic

A Au/CuNiCoS₄/p-Si photodiode: electrical and morphological characterization

• Adem Koçyiğit,
• Adem Sarılmaz,
• Teoman Öztürk,
• Faruk Ozel and
• Murat Yıldırım

Beilstein J. Nanotechnol. 2021, 12, 984–994, doi:10.3762/bjnano.12.74

• have revealed that the bandgap value is suitable for optoelectronic devices. To the best of our knowledge, there is no study on the electrical properties of CuNiCoS4-based photodiodes. The usage of different materials as interfacial layers in metal–semiconductor devices is a hot research topic

• from 1200 to 300 nm, which is compatible with the absorbance result. The optical bandgap of thiospinel CuNiCoS4 was calculated from the Tauc and Kubelka–Munk equations. The graph of (F(R∞)hν)2 as function of the photon energy was plotted to estimate the bandgap of nanocrystals with direct band

• transition [8]. The bandgap was determined as 1.66 eV by extrapolating the linear portion of the band energy graph given in Figure 3b. Electrical properties In order to determine the electrical performance of the Au/CuNiCoS4/p-Si device, I–V measurements were performed on the photodiode in the dark and under

Molecular assemblies on surfaces: towards physical and electronic decoupling of organic molecules

• Sabine Maier and
• Meike Stöhr

Beilstein J. Nanotechnol. 2021, 12, 950–956, doi:10.3762/bjnano.12.71

• of the substrate, for instance by adding or intercalating a decoupling layer, are often the better choice. In the best case, these interfacial layers have a large bandgap to prevent a hybridization with molecular states as well as with the metallic/semiconducting substrate. All the strategies for

• inertness and the low density of states near the Fermi level. However, the electronic decoupling efficiency also depends on the electronic structure of the 2D material. Sometimes, only molecular states in the bandgap of the 2D material can be decoupled. Moreover, ultrathin organic spacer layers can

• bandgap. Hence, Yousofnejad et al. [85] found using MoS2 on Ag(111) as substrate that the HOMO of tetracyanoquinodimethane (TNCQ) is not decoupled because it is located in the MoS2 valence band, while the lowest unoccupied molecular orbital narrows but still suffers from lifetime broadening because it is

Comprehensive review on ultrasound-responsive theranostic nanomaterials: mechanisms, structures and medical applications

• Sepand Tehrani Fateh,
• Lida Moradi,
• Elmira Kohan,
• Michael R. Hamblin and
• Amin Shiralizadeh Dezfuli

Beilstein J. Nanotechnol. 2021, 12, 808–862, doi:10.3762/bjnano.12.64

9.1% efficient zinc oxide/silicon solar cells on a 50 μm thick Si absorber

• Rafal Pietruszka,
• Bartlomiej S. Witkowski,
• Monika Ozga,
• Katarzyna Gwozdz,
• Ewa Placzek-Popko and
• Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 766–774, doi:10.3762/bjnano.12.60

• ) measurements were visible. Figure 5a shows the EQE as a function of the wavelength. The measurements were carried out in the wavelength range from 300 to 1200 nm. For photon energies greater than the ZnO bandgap, significant contributions to the external quantum efficiency were not observed. High-energy

• silicon). For photon energies lower than the ZnO bandgap, the rapid increase of the EQE value was observed. The photovoltaic cell effectively separates e–h pairs in the wavelength range from 370 to 850 nm. The average EQE values were at the level of 50%. There were clearly visible interference peaks for

Prediction of Co and Ru nanocluster morphology on 2D MoS₂ from interaction energies

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2021, 12, 704–724, doi:10.3762/bjnano.12.56

• adsorption. The metal d-orbital contribution increases for both Co and Ru as more adatoms are added, causing the total DOS to become increasingly more metallic compared to bare MoS2, which is a semiconductor. Metal d-orbital states appear in the bandgap for as little as a single adatom. These increase in

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

High-yield synthesis of silver nanowires for transparent conducting PET films

• Gul Naz,
• Hafsa Asghar,
• Muhammad Ramzan,
• Muhammad Arshad,
• Rashid Ahmed,
• Muhammad Bilal Tahir,
• Bakhtiar Ul Haq,
• Nadeem Baig and
• Junaid Jalil

Beilstein J. Nanotechnol. 2021, 12, 624–632, doi:10.3762/bjnano.12.51

• . These peaks depict transitions at different energy levels within the bandgap. The AgNWs prepared in this experiment give red emission that attributed to deep holes. Figure 3d shows the transmittance spectra of AgNW-loaded PET films. The transmittance (T) of the as-fabricated PET films was determined by

Nanoporous and nonporous conjugated donor–acceptor polymer semiconductors for photocatalytic hydrogen production

• Zhao-Qi Sheng,
• Yu-Qin Xing,
• Yan Chen,
• Guang Zhang,
• Shi-Yong Liu and
• Long Chen

Beilstein J. Nanotechnol. 2021, 12, 607–623, doi:10.3762/bjnano.12.50

• tuning the bandgap, enlarging the surface area, enabling more efficient separation of electron–hole pairs, and enhancing the charge carrier mobility. In particular, donor–acceptor (D–A) polymers were demonstrated as a promising platform to develop high-performance photocatalysts due to their easily

• , for example, La, Bi, and Ta, which are often rare, toxic, and expensive [6]. Also, expensive noble metal-based cocatalysts (e.g., Pt) are required to improve the photocatalytic performance. As such, an ideal photocatalyst for water splitting reaction should fit the following criteria: suitable bandgap

• photocatalysts with narrow bandgap and high charge carrier mobility could, therefore, facilitate light harvesting and the reduction of protons [38]. In terms of structural design, D–A polymers are a good platform to narrow the bandgap, enhance the charge carrier mobility and promote electron–hole separation