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

Impact of GaAs(100) surface preparation on EQE of AZO/Al₂O₃/p-GaAs photovoltaic structures

• Piotr Caban,
• Rafał Pietruszka,
• Jarosław Kaszewski,
• Monika Ożga,
• Bartłomiej S. Witkowski,
• Krzysztof Kopalko,
• Piotr Kuźmiuk,
• Katarzyna Gwóźdź,
• Ewa Płaczek-Popko,
• Krystyna Lawniczak-Jablonska and
• Marek Godlewski

Beilstein J. Nanotechnol. 2021, 12, 578–592, doi:10.3762/bjnano.12.48

• ) properties and bandgap measurements of the deposited layers were also reported. The highest EQE value was obtained for the samples initially etched with a citric acid-based etchant and, in the last preparation step, either passivated with ammonium sulfide aqueous solution or treated with ammonium hydroxide

• intensities of NBE and DLE change depending on the GaAs surface preparation method. However, there is no clear correlation between the use of SA10 for GaAs passivation and the luminescence of the AZO layer. Bandgap size of the AZO layers Various surface treatments conducted in four different stages (see

• Figure 1) might induce specific initial growth conditions of proximate layers, possibly resulting in various bandgap sizes of deposited AZO. In order to verify the influence of potential differences of Eg on the quantum efficiency of the devices, reflectance (diffuse and specular) examinations were

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

• Abhishek Grewal,
• Yuqi Wang,
• Matthias Münks,
• Klaus Kern and
• Markus Ternes

Beilstein J. Nanotechnol. 2021, 12, 559–565, doi:10.3762/bjnano.12.46

• materials at the nanoscale. In this work, we study hexagonal boron nitride (h-BN), an atomically thin 2D layer, that is van der Waals-coupled to a Cu(111) surface. The system is of interest as a decoupling layer for functional 2D heterostructures due to the preservation of the h-BN bandgap and as a template

• for graphene and MoS2-based electronics utilising the small lattice mismatch, the large optical phonon modes, and particularly the large bandgap [3][4][5][6][7][8][9][10]. Furthermore, when grown on metal substrates h-BN can be used as a nanoscale template for atoms, molecules, and nanostructures with

• ]. Recently, however, Zhang et al. used STM in combination with DFT simulations to study the variation of the local work function and bandgap within the Moiré superlattice and found that the variation depends on the angle of the Moiré with respect to the substrate lattice, but inferred only marginal structure

Influence of electrospray deposition on C₆₀ molecular assemblies

• Antoine Hinaut,
• Sebastian Scherb,
• Sara Freund,
• Zhao Liu,
• Thilo Glatzel and
• Ernst Meyer

Beilstein J. Nanotechnol. 2021, 12, 552–558, doi:10.3762/bjnano.12.45

• used as model surface in nc-AFM measurements [31][32][33][34], and, finally, NiO(001), a p-type wide-bandgap metal oxide with potential applications in photovoltaics [35][36][37]. For all cases, we show the typical C60 structures formed by TE and compare these with the results from HV-ESD. This allows

• molecular trapping and their creation is therefore studied for those reasons [32][43][45][46]. In HV-ESD deposition, their presence can be reduced but not inhibited without annealing of the surface [44]. C60 on NiO(001) surface NiO is a wide-bandgap metal oxide with potential applications in organic

Boosting of photocatalytic hydrogen evolution via chlorine doping of polymeric carbon nitride

• Malgorzata Aleksandrzak,
• Michalina Kijaczko,
• Wojciech Kukulka,
• Daria Baranowska,
• Martyna Baca,
• Beata Zielinska and
• Ewa Mijowska

Beilstein J. Nanotechnol. 2021, 12, 473–484, doi:10.3762/bjnano.12.38

• the hydrogen evolution reaction. The following aspects were found to enhance the photocatalytic efficiency of Cl-PCN: (i) unique location of Cl atoms at the interlayers of PCN instead of on its π-conjugated planes, (ii) slight bandgap narrowing, (iii) lower recombination rate of the electron–hole

• -PCN were investigated via UV–vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) emission spectroscopy. Figure 8a shows the Kubelka–Munk function curves of the fabricated materials. The bandgap is 2.78 and 2.77 eV for PCN and Cl-PCN, respectively, indicating that the Cl-doping had no

• significant effect on the bandgap shift. This might be attributed to the low content of chlorine atoms in the material. The PL spectra of PCN and Cl-PCN are presented in Figure 8b. The emission peak of PCN is located at approx. 440 nm, which is in accordance with the optical bandgap defined by the DRS

Structural and optical characteristics determined by the sputtering deposition conditions of oxide thin films

• Petronela Prepelita,
• Florin Garoi and
• Valentin Craciun

Beilstein J. Nanotechnol. 2021, 12, 354–365, doi:10.3762/bjnano.12.29

• thickness. The optical constants (i.e., the refractive index n, the extinction coefficient k, and the absorption coefficient α) of the SiO2 and ZnO oxide films were determined from the transmission spectra recorded in the range of 190–2500 nm by using the Swanepoel method, while the energy bandgap was

• as SiO2 and ZnO, are used to build devices with metasurface structures whose properties can be observed in the visible spectrum. They are intensely investigated due to their versatile properties, such as high transmission in the visible range [12][13] and broad energy bandgap [14][15][16], among

• ZnO thin films, between the extinction coefficient, k, (Figure 9) and the absorption coefficient, α, there is this following relation: where λ is the wavelength. We determined the optical bandgap, corresponding to the direct optical transitions, by extrapolating the linear portion of the dependency

Nickel nanoparticle-decorated reduced graphene oxide/WO₃ nanocomposite – a promising candidate for gas sensing

• Ilka Simon,
• Alexandr Savitsky,
• Rolf Mülhaupt,
• Vladimir Pankov and
• Christoph Janiak

Beilstein J. Nanotechnol. 2021, 12, 343–353, doi:10.3762/bjnano.12.28

• 200 to 400 °C, which means a high power consumption [4]. WO3 is a wide-bandgap [12][13] n-type semiconductor [14][15] with good sensitivity towards NO2 [16] and CO [17]. Known successful routes to improve the MOS gas sensing performance are doping with transition metals, decoration with noble metals

• , formation of heterojunctions, or size reduction [18][19]. Doping of WO3 with nickel improves the humidity sensing compared to neat WO3. Attributed to a greater number of electrons donated by Ni atoms, higher surface area, and smaller bandgap energy, Ni-doped WO3 has a faster response, higher sensitivity

Extended iron phthalocyanine islands self-assembled on a Ge(001):H surface

• Rafal Zuzak,
• Marek Szymonski and
• Szymon Godlewski

Beilstein J. Nanotechnol. 2021, 12, 232–241, doi:10.3762/bjnano.12.19

• associated with the bandgap of the FePc island. The gap reaches approximately 2.7 eV, which correlates well with the recently reported data for FePc on graphene where the molecules were decoupled from the substrate [17]. Therefore, our results suggest that the FePc islands are well isolated electronically

ZnO and MXenes as electrode materials for supercapacitor devices

• Ameen Uddin Ammar,
• Ipek Deniz Yildirim,
• Feray Bakan and
• Emre Erdem

Beilstein J. Nanotechnol. 2021, 12, 49–57, doi:10.3762/bjnano.12.4

• in semiconductors is fundamentally the same, regardless of composition. Defects generate bandgap states that either generate electrons in the conduction band or holes in the valence band. Therefore, we believe that the discussion, based on experimental results, of the magnitude of this effect for 2D

• and 3D materials will be of utmost benefit to the interested community. Review ZnO as electrode material for supercapacitors Zinc oxide (ZnO) is a highly defective semiconductor material, regardless of its synthesis route, that has a large bandgap energy (Eg) at room temperature. However, defect types

• environment of the lattice atoms and defects. With the aid of advanced characterization techniques one may get valuable information on site symmetry, atomic bonding, and, in particular, on the bandgap energy of semiconductors. Raman, photoluminescence (PL), UV–vis, and electron paramagnetic resonance (EPR

Kondo effects in small-bandgap carbon nanotube quantum dots

• Patryk Florków,
• Damian Krychowski and
• Stanisław Lipiński

Beilstein J. Nanotechnol. 2020, 11, 1873–1890, doi:10.3762/bjnano.11.169

• Patryk Florkow Damian Krychowski Stanislaw Lipinski Department of Theory of Nanostructures, Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17,60-179 Poznań, Poland 10.3762/bjnano.11.169 Abstract We study the magnetoconductance of small-bandgap carbon nanotube

• periodic conditions along the circumference. When the closest quantization line misses the K point, a bandgap appears. The bandgap depends on the minimum separation of the circular quantization lines from the Dirac points. The semiconducting gaps are of the order of a few hundred millielectronvolts [9

• ][46][47], other perturbations such as axial strain or twists can shift the dispersion cones in CNTs and open the bandgap [44][48][49][50]. Unlike the quantization bandgaps, which depend on the inverse of the diameter, these narrow perturbation gaps are inversely proportional to the square of the

Unravelling the interfacial interaction in mesoporous SiO₂@nickel phyllosilicate/TiO₂ core–shell nanostructures for photocatalytic activity

• Bridget K. Mutuma,
• Xiluva Mathebula,
• Isaac Nongwe,
• Bonakele P. Mtolo,
• Boitumelo J. Matsoso,
• Rudolph Erasmus,
• Zikhona Tetana and
• Neil J. Coville

Beilstein J. Nanotechnol. 2020, 11, 1834–1846, doi:10.3762/bjnano.11.165

• yielded the mSiO2@NiPS/TiO2 composite. The bandgap energy of mSiO2@NiPS and of mSiO2@NiPS/TiO2 were estimated to be 2.05 and 2.68 eV, respectively, indicating the role of titania in tuning the optoelectronic properties of the SiO2@nickel phyllosilicate. As a proof of concept, the core–shell nanostructures

• the core–shell nanostructure and yielded superior photocatalytic properties. Keywords: bandgap energy; core–shell; dye degradation; nickel phyllosilicate; photocatalysts; Introduction Textile dyes and organic compounds are major water pollutants, which create an environmental hazard to aquatic

• brookite phases, the anatase phase has been extensively used for photocatalysis owing to its enhanced surface properties [7][8][9][10]. In a typical photocatalytic process, photons of energy greater than the bandgap energy of TiO2 excite electrons to the conduction band leaving holes in the valence band

Nanocasting synthesis of BiFeO₃ nanoparticles with enhanced visible-light photocatalytic activity

• Thomas Cadenbach,
• Maria J. Benitez,
• A. Lucia Morales,
• Cesar Costa Vera,
• Luis Lascano,
• Francisco Quiroz,
• Alexis Debut and
• Karla Vizuete

Beilstein J. Nanotechnol. 2020, 11, 1822–1833, doi:10.3762/bjnano.11.164

• photocatalysts with narrow bandgaps in the visible-light region in combination with a slow electron–hole recombination has attracted a great deal of interest [18]. Bismuth ferrite (BiFeO3) is one of those photocatalysts and has been intensively researched in the past few years due to its narrow bandgap in the

• the particle size. The smaller the particle, the greater the specific surface area is and, thus, the more active sites are available for photodegradation [15][18]. In addition, it was shown that size and shape of BiFeO3 particles have a direct influence on the bandgap of the material. Smaller BiFeO3

• electron microscope (TEM). Fourier-transform infrared (FTIR) spectra of the nanoscale materials were recorded using a Jasco FT IR-4700 spectrometer. Bandgap information was obtained using the spectra recorded in a Perkin Elmer UV–vis spectrometer with an integrating sphere. Spectra were suitably

Absorption and photoconductivity spectra of amorphous multilayer structures

• Oxana Iaseniuc and
• Mihail Iovu

Beilstein J. Nanotechnol. 2020, 11, 1757–1763, doi:10.3762/bjnano.11.158

• of the photocurrent spectra is attributed to the different values of the optical bandgap of the involved amorphous layers (Eg ≈ 2.0 eV for As0.40S0.30Se0.30 and Ge0.09As0.09Se0.82 and Eg ≈ 3.0 eV for Ge0.30As0.04S0.66). The obtained experimental results are discussed taking into account the light

• mono- and bimolecular and that the transport is controlled through multiple trapping processes with exponential distribution of the localized states in the bandgap. Regarding the physics and applications of chalcogenide materials, multilayered amorphous thin-film structures are especially interesting

• ), Ge0.09As0.09Se0.82 (2), As0.40S0.30Se0.30 (3), and the HS As0.40S0.30Se0.30/Ge0.09As0.09Se0.82/Ge0.30As0.04S0.66 (4). The thin film layer Ge0.30As0.04S0.66 with the largest bandgap energy, Eg ≈ 3.0 eV [11], which was placed on the top of the multilayer structure, has a thickness of d ≈ 200 nm and was transparent to

The influence of an interfacial hBN layer on the fluorescence of an organic molecule

• Christine Brülke,
• Oliver Bauer and
• Moritz M. Sokolowski

Beilstein J. Nanotechnol. 2020, 11, 1663–1684, doi:10.3762/bjnano.11.149

• order to support tunneling [11][12][13]. A single layer or films of hBN are attractive for decoupling a molecule from an underlying metal substrate as hBN exhibits a wide bandgap of 5.9 eV [14]. Perspectively, it could also provide a substrate for STM-LE experiments. Furthermore, it is of interest due

• bandgap of hBN, as indicated in Figure 1b. This is in agreement with the findings by Martínez-Galera et al. for PTCDA/hBN/Rh(110) [34]. From scanning tunneling spectroscopy (STS) experiments, the authors concluded that the coupling is only weak. They deduced further that the CT (in the ground state

A self-powered, flexible ultra-thin Si/ZnO nanowire photodetector as full-spectrum optical sensor and pyroelectric nanogenerator

• Liang Chen,
• Jianqi Dong,
• Miao He and
• Xingfu Wang

Beilstein J. Nanotechnol. 2020, 11, 1623–1630, doi:10.3762/bjnano.11.145

• wide bandgap (3.2 eV), which absorbs UV light and can be easily prepared [11][12]. A pyroelectric potential will be generated in ZnO when the temperature changes upon illumination. The internal electric field can effectively drive the flow of electrons through an external circuit, yielding a short

• -powered PDs yields full-spectrum (UV–visible–NIR) detection. The broad spectral photoresponse from UV to NIR is related to two different bandgap materials (wide bandgap = 3.2 eV and narrow bandgap = 1.1 eV). Remarkably, the photoresponse current is significantly enhanced by introducing the pyroelectric

High-responsivity hybrid α-Ag₂S/Si photodetector prepared by pulsed laser ablation in liquid

• Raid A. Ismail,
• Hanan A. Rawdhan and
• Duha S. Ahmed

Beilstein J. Nanotechnol. 2020, 11, 1596–1607, doi:10.3762/bjnano.11.142

• fabricated by a chemical method. They show that the Ag2S quantum dots (QDs) planted on the surface of Si create impurity states in the Si bandgap. In pulsed laser ablation, the interaction between laser and material particles leads to severe particle aggregation and broad particle size distributions via