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

• optical bandgap and work function is thoroughly investigated by employing various spectroscopic and microscopic techniques. The systematic investigation of the work function of the films reveals a distinct trend with thickness, originating from the thickness-dependent defect concentration within the films

• for indirect transitions). The optical bandgap values (considering an indirect transition in WO3) of the as-deposited and annealed films are estimated from (αhv)1/2 versus hv plots (Tauc plots, see Figure S3 in Supporting Information File 1). Figure 2b shows the optical bandgap variation of WOx films

• variability in bandgap energies, we recall that the optical bandgap of this class of materials is a function of defect density and stoichiometric composition, which is mainly governed by the OV concentration within the films [39][40]. To probe any possible variation in OV concentration and stoichiometry

A visible-light photodetector based on heterojunctions between CuO nanoparticles and ZnO nanorods

• Doan Nhat Giang,
• Nhat Minh Nguyen,
• Duc Anh Ngo,
• Thanh Trang Tran,
• Le Thai Duy,
• Cong Khanh Tran,
• Thi Thanh Van Tran,
• Phan Phuong Ha La and
• Vinh Quang Dang

Beilstein J. Nanotechnol. 2023, 14, 1018–1027, doi:10.3762/bjnano.14.84

• NPs were successfully decorated onto ZnO NRs; this enhanced the absorption ability from UV to the visible-light region because of the narrow optical bandgap of the CuO NPs/ZnO NRs heterojunction. The recorded highest photocurrent was 10 μA under 1.28 mW·cm−2 illumination at 395 nm and 2 V bias. The

Electrical and optical enhancement of ITO/Mo bilayer thin films via laser annealing

• Abdelbaki Hacini,
• Ahmad Hadi Ali,
• Nurul Nadia Adnan and
• Nafarizal Nayan

Beilstein J. Nanotechnol. 2022, 13, 1589–1595, doi:10.3762/bjnano.13.133

• crystalline improvement leads to less light scattering in the metal layer [29][30]. Moreover, laser annealing reduces the defects, including grain boundaries and impurities, reducing light scattering and photon–electron interactions [29][30][31]. The optical bandgap energy Eg of ITO/Mo thin film was studied

• optical bandgap. Electrical properties of ITO/Mo and ITO films obtained from four-point probe measurements are shown in Figure 6. The results exhibit a decrease in the resistivity from 15.63 × 10−4 to 1.73 × 10−4 Ω/cm, for the as-deposited sample and the sample annealed at 120 mJ. An increase in

Photoelectrochemical water oxidation over TiO₂ nanotubes modified with MoS₂ and g-C₃N₄

• Phuong Hoang Nguyen,
• Thi Minh Cao,
• Tho Truong Nguyen,
• Hien Duy Tong and
• Viet Van Pham

Beilstein J. Nanotechnol. 2022, 13, 1541–1550, doi:10.3762/bjnano.13.127

• spectroscopy (DRS) was carried out to measure the optical bandgap of the semiconductor materials through the Tauc method using the absorption coefficient α of the material, according to Equation 1 [42]: where h, ν, Eg, and B are the Planck constant, the frequency of the photon, the bandgap energy, and a

• visible-light range in comparison to that of the remaining samples. To evaluate the optical bandgap energy of TNAs and g-C3N4, Tauc plots were extrapolated in Figure 4b. The bandgap values of TNAs, g-C3N4, and MoS2 were calculated as about 3.15, 2.67, and 1.47 eV, respectively. These results are agreement

A TiO₂@MWCNTs nanocomposite photoanode for solar-driven water splitting

• Anh Quynh Huu Le,
• Ngoc Nhu Thi Nguyen,
• Hai Duy Tran,
• Van-Huy Nguyen and
• Le-Hai Tran

Beilstein J. Nanotechnol. 2022, 13, 1520–1530, doi:10.3762/bjnano.13.125

• -scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and linear sweep voltammetry. The results show that the TiO2@MWCNTs nanocomposite has an optical bandgap of 2.5 eV, which is a significant improvement in visible-light absorption capability compared to TiO2 (3.14 eV). The

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

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

• 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

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

• increasing film thickness [45]. Zhou et al. indicated that the direct bandgap transition of SnO2 has an absorption coefficient α and the optical bandgap (Eg) can be determined by the calculation of α(hν)2 ∝ (hν − Eg)1/2/hν, and the plot of α(hν)2 vs photon energy hν, respectively. For example, the bandgap of

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

• energy, and then another broader peak is observed at ≈10 eV in which α(ω) reaches its maximum value of 154.23 104/cm. From the literature, we have noted that the α-SnSe has an indirect bandgap of 0.9 eV and a direct gap of 1.3 eV [5][74][75][76]. On the other hand, the optical bandgap value of the 2D

• in Figure 12d as a function of photon energy. It can be seen from Figure 12d that there is no real optical conductivity σ(ω) found in the optical bandgap of this compound, which proves the nonexistence of electrons in unoccupied bands. After the photon energy value of 1.4 eV, there is an abrupt

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

• 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

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

• pyrazole-triazine-based CTFs, that is, P9 (A–D–A) and P10 (D–A) (Figure 2) by a metal-free catalyzed approach [50]. Compared with P10, introducing a benzothiadiazole unit into P9 effectively reduced the optical bandgap from 2.94 eV to the ideal value of 2.33 eV. They further probed the influence of

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

• 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

• 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

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

• support for TiO2 creating a photocatalyst with improved photoactivity due to the presence of more active sites for the adsorption of the MV dye molecules. Additionally, from the diffuse reflectance UV–vis data, an optical bandgap of approximately 2.05 eV was obtained for mSiO2@NiPS while that of mSiO2

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

Recent progress in perovskite solar cells: the perovskite layer

• Xianfeng Dai,
• Ke Xu and
• Fanan Wei

Beilstein J. Nanotechnol. 2020, 11, 51–60, doi:10.3762/bjnano.11.5

• perovskites is lower than that of their 3D counterparts because of the lower carrier mobility, the wide optical bandgap, the low conductivity and the large exciton binding energy. Therefore, Priya et al. [8] created a methylammonium (MA)-based 2D perovskite film by using the vapor-fumigation technique. The

Charge-transfer interactions between fullerenes and a mesoporous tetrathiafulvalene-based metal–organic framework

• Manuel Souto,
• Joaquín Calbo,
• Samuel Mañas-Valero,
• Aron Walsh and
• Guillermo Mínguez Espallargas

Beilstein J. Nanotechnol. 2019, 10, 1883–1893, doi:10.3762/bjnano.10.183

• intermolecular CT excitation between the C60 and TTF ligands, as supported by theoretical calculations (see below). The experimental optical bandgap calculated from the onset is near 1.4 eV (885 nm), which is in agreement with the calculated electrochemical bandgap (1.43 eV) since the redox potential of TTF

Zn/F-doped tin oxide nanoparticles synthesized by laser pyrolysis: structural and optical properties

• Florian Dumitrache,
• Iuliana P. Morjan,
• Elena Dutu,
• Ion Morjan,
• Claudiu Teodor Fleaca,
• Monica Scarisoreanu,
• Alina Ilie,
• Marius Dumitru,
• Cristian Mihailescu,
• Adriana Smarandache and
• Gabriel Prodan

Beilstein J. Nanotechnol. 2019, 10, 9–21, doi:10.3762/bjnano.10.2

• dopant concentration). Keywords: laser pyrolysis; nanoparticles; optical bandgap; Zn/F-doped SnO2; Introduction Recently, there has been growing interest in the field of transparent conducting oxides and wide bandgap oxide nanocrystalline materials such as tin oxide (SnO2). It is generally agreed that

Lead-free hybrid perovskites for photovoltaics

• Oleksandr Stroyuk

Beilstein J. Nanotechnol. 2018, 9, 2209–2235, doi:10.3762/bjnano.9.207

• 1.79 eV and an increase of the solar cell performance (Figure 3c) from 8.25% for the undoped Pb-HP to 11.33% for the CsSn0.1Pb0.9IBr2-based device [69]. The latter cell also exhibited a record Voc of 1.26 V amounting to ≈70% of the optical bandgap and vividly showing a high potential of such

Sb₂S₃ grown by ultrasonic spray pyrolysis and its application in a hybrid solar cell

• Erki Kärber,
• Atanas Katerski,
• Ilona Oja Acik,
• Arvo Mere,
• Valdek Mikli and
• Malle Krunks

Beilstein J. Nanotechnol. 2016, 7, 1662–1673, doi:10.3762/bjnano.7.158

• between the Sb/S ratio in the films and the corresponding values of Eg suggest that values around 1.6 eV are expected for crystalline and stoichiometric Sb2S3 (S/Sb = 1.5) films [60]. Thus, based on the low optical bandgap of 1.6 eV, along with the S/Sb ratio of 1.53 obtained by EDX, we can deduce that

Optical absorption signature of a self-assembled dye monolayer on graphene

• Tessnim Sghaier,
• Sylvain Le Liepvre,
• Céline Fiorini,
• Ludovic Douillard and
• Fabrice Charra

Beilstein J. Nanotechnol. 2016, 7, 862–868, doi:10.3762/bjnano.7.78

• changes of the optical bandgap. However, alkyl chains present here should reduce such interactions by maintaining the conjugated moiety at a larger distance from graphene. This is substantiated by the preservation of the absorption line-shape and the balance between vibronic contributions. This also means

An insight into the mechanism of charge-transfer of hybrid polymer:ternary/quaternary chalcopyrite colloidal nanocrystals

• Parul Chawla,
• Son Singh and
• Shailesh Narain Sharma

Beilstein J. Nanotechnol. 2014, 5, 1235–1244, doi:10.3762/bjnano.5.137

• in Figure 3C(a–c), which shows the enhancement of the optical bandgap (as calculated from the Tauc’s plot involving the absorption coefficient, α and the photon energy hν) from CISe to CZTSe. The bandgap values of pristine CISe, CIGSe and CZTSe are ≈1.03 eV, 1.1 eV and 1.15 eV, respectively (Figure

Surface passivation and optical characterization of Al₂O₃/a-SiC_x stacks on c-Si substrates

• Gema López,
• Pablo R. Ortega,
• Cristóbal Voz,
• Isidro Martín,
• Mónica Colina,
• Anna B. Morales,
• Albert Orpella and
• Ramón Alcubilla

Beilstein J. Nanotechnol. 2013, 4, 726–731, doi:10.3762/bjnano.4.82

• and glass respectively. The results of the absorbance measurements are shown in Figure 2. Other works have previously reported an optical bandgap of Eopt = 6.4 ± 0.1 eV for as-deposited and annealed ALD Al2O3 films [18]. This means that this material is transparent for wavelengths above 200 nm

Photoelectrochemical and Raman characterization of In₂O₃ mesoporous films sensitized by CdS nanoparticles

• Mikalai V. Malashchonak,
• Sergey K. Poznyak,
• Eugene A. Streltsov,
• Anatoly I. Kulak,
• Olga V. Korolik and
• Alexander V. Mazanik

Beilstein J. Nanotechnol. 2013, 4, 255–261, doi:10.3762/bjnano.4.27

• optical bandgap of bulk CdS. The observed increase in Eg with the decreasing number of SILAR cycles can be explained by the well-known quantum-confinement effect related to the discretization of energy levels in nanoparticles and the increase in the energy gap between LUMO and HOMO levels with the