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

• spectra of the prepared catalysts are shown in Figure 6b. The optical absorption of TiO2 is in the UV region, while the light absorption edge of TiO2@MWCNTs redshifts to the visible-light region. As seen from the Tauc plots (inset of Figure 6b), the optical band gap of TiO2 and TiO2@MWCNTs catalysts are

• exhibits poor hydrogen production under sunlight irradiation. It could be explained by the 3.14 eV optical band gap of TiO2, which absorbs only UV light. In addition, the fast recombination of the photogenerated (h+/e−) pairs contributes to the poor photochemical catalysis activity of the TiO2 electrode

Revealing the formation mechanism and band gap tuning of Sb₂S₃ nanoparticles

• Maximilian Joschko,
• Franck Yvan Fotue Wafo,
• Christina Malsi,
• Danilo Kisić,
• Ivana Validžić and
• Christina Graf

Beilstein J. Nanotechnol. 2021, 12, 1021–1033, doi:10.3762/bjnano.12.76

• reaction allowed tuning of the optical band gap of the amorphous nanoparticles in the range of 2.2–2.0 eV. On the contrary, the optical band gap of the crystalline particles decreased to a value of 1.7 eV and remained constant when the reaction progressed. Based on the proposed formation mechanism, future

• . Subsequently, the type I nanoparticles aggregated into type II nanoparticles and formed superordinated type III structures that finally crystallized in an orthorhombic crystal structure. Furthermore, the kinetic control of the reaction enabled tuning of the optical band gap of the amorphous material in the

• range of 2.18 ± 0.03 to 2.01 ± 0.03 eV. In contrast, the optical band gap of the crystalline particles decreased to a value of 1.71 ± 0.03 eV and did not change any further. The reduction of the mobility gap of the amorphous states of the particles was likely due to an electronic relaxation effect with

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

• with CTAB due to quantum size effects [31]. The absorption of the Ag2S NPs decreased sharply above λ = 302 nm for Ag2S prepared in pure Tu solution, while it decreased slowly for Ag2S prepared in Tu with CTAB, indicating different absorption edges. The optical band gap of the Ag2S NPs prepared in pure

Rapid thermal annealing for high-quality ITO thin films deposited by radio-frequency magnetron sputtering

• Petronela Prepelita,
• Ionel Stavarache,
• Doina Craciun,
• Florin Garoi,
• Catalin Negrila,
• Beatrice Gabriela Sbarcea and
• Valentin Craciun

Beilstein J. Nanotechnol. 2019, 10, 1511–1522, doi:10.3762/bjnano.10.149

• treatment on the ITO chemical composition. Using a Tauc plot, values of the optical band gap ranging from 3.17 to 3.67 eV were estimated. These values depend on the heat treatment and the thickness of the sample. Highly conductive indium tin oxide thin films (ρ = 7.4 × 10−5 Ω cm) were obtained after RTA

Uniform Sb₂S₃ optical coatings by chemical spray method

• Jako S. Eensalu,
• Atanas Katerski,
• Erki Kärber,
• Ilona Oja Acik,
• Arvo Mere and
• Malle Krunks

Beilstein J. Nanotechnol. 2019, 10, 198–210, doi:10.3762/bjnano.10.18

• )1/r vs hν, where h is the Planck constant, ν is the frequency and r = 1/2 is the exponent corresponding to the assumed direct optical transition [57]. Extrapolating the linear region of this curve to the hν-axis yields the optical band gap. Thin film interference could not be completely removed by

Electrospun one-dimensional nanostructures: a new horizon for gas sensing materials

• Muhammad Imran,
• Nunzio Motta and
• Mahnaz Shafiei

Beilstein J. Nanotechnol. 2018, 9, 2128–2170, doi:10.3762/bjnano.9.202

• type of ZnO doping is with indium, for which the product is called “IZO”. When the amount of indium is greater than 0.05, amorphous In2O3 forms and leads to a pronounced decrease in grain size. The optical band gap energy of IZO NTs also decreases with increased doping levels. Doped indium atoms may

Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

• Sri Kasi Matta,
• Chunmei Zhang,
• Yalong Jiao,
• Anthony O'Mullane and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1247–1253, doi:10.3762/bjnano.9.116

• GW results, the BSE method was adopted to obtain the light absorption spectrum [21][22] and the optical band gap. BSE was solved by using the ten highest valance bands and ten lowest conduction bands and with a 13 × 5 × 1 k-grid. Using the band gaps obtained from GW and BSE functional methods the

Facile synthesis of a ZnO–BiOI p–n nano-heterojunction with excellent visible-light photocatalytic activity

• Mengyuan Zhang,
• Jiaqian Qin,
• Pengfei Yu,
• Bing Zhang,
• Mingzhen Ma,
• Xinyu Zhang and
• Riping Liu

Beilstein J. Nanotechnol. 2018, 9, 789–800, doi:10.3762/bjnano.9.72

• to 1:4 displayed a gradually decreasing adsorption edge from the visible light range to the ultraviolet region. To determine the conduction positions, the Tauc relation is utilized to estimate the optical band gap. According to the following relational expression proposed by Tauc, Davis and Mott

• : where h is Plank’s constant, ν is the frequency of vibration, α is the adsorption coefficient, Eg is the optical band gap and A is a proportionality constant [51][52]. The value of the constant n denotes the characteristics in the transition of a semiconductor. For the case that both ZnO and BiOI

• 1:2). Schematic band energy diagram of BiOI and ZnO before (a) and after (b) interfacial contact. The optical band gap, degree of degradation for 100 min and the reaction rate coefficient of the as-prepared samples as compared to the reference samples (blanks). Supporting Information Supporting

Hydrothermal synthesis of ZnO quantum dot/KNb₃O₈ nanosheet photocatalysts for reducing carbon dioxide to methanol

• Xiao Shao,
• Weiyue Xin and
• Xiaohong Yin

Beilstein J. Nanotechnol. 2017, 8, 2264–2270, doi:10.3762/bjnano.8.226

• displayed an absorption threshold at 376 nm. Compared with the pure KNb3O8 nanosheets, we found a significant red-shift of the absorption edge, which could attribute to the enhancement observed by the ZnO quantum dots upon visible-light absorption. The optical band gap (Eg) of semiconductors could be

Performance of colloidal CdS sensitized solar cells with ZnO nanorods/nanoparticles

• Anurag Roy,
• Partha Pratim Das,
• Mukta Tathavadekar,
• Sumita Das and
• Parukuttyamma Sujatha Devi

Beilstein J. Nanotechnol. 2017, 8, 210–221, doi:10.3762/bjnano.8.23

• Henglein’s empirical equation [39]. The corresponding optical band gap was calculated to be 2.33 eV from the Tauc plot, considering allowed direct transition for synthesized CdS NPs (inset of Figure 2c). The emission spectrum of CdS NPs was monitored at room temperature by varying the excitation wavelength

• NPs. (c) UV–vis absorption spectrum (Inset: corresponding Tauc Plot for optical band gap measurement) and (d) excitation wavelength dependent emission spectra of the CdS NP dispersion at room temperature. (a) Respective X-ray diffraction patterns of the CdS-sensitized ZnO-P and ZnO-R films. (b

Characterization of nanostructured ZnO thin films deposited through vacuum evaporation

• Jose Alberto Alvarado,
• Arturo Maldonado,
• Héctor Juarez,
• Mauricio Pacio and
• Rene Perez

Beilstein J. Nanotechnol. 2015, 6, 971–975, doi:10.3762/bjnano.6.100

• appears in this spectrum is attributed to the porosity of this material and the spaces between the nanostructures; this is confirmed by the HRSEM images. Estimation of the optical band gap Ignoring the reflectivity, which is expected to be low, the coefficient α may be determined from the results of the

• transmittance by using Equation 1: where d is the thickness of the thin film, and T is measured transmission. In consequence, the relation between the coefficient and the photon energy for direct transition is , where A is a constant, Eg is the optical band gap, the plot of this relation has a linear region

Transformation of hydrogen titanate nanoribbons to TiO₂ nanoribbons and the influence of the transformation strategies on the photocatalytic performance

• Melita Rutar,
• Nejc Rozman,
• Matej Pregelj,
• Carla Bittencourt,
• Romana Cerc Korošec,
• Andrijana Sever Škapin,
• Aleš Mrzel,
• Srečo D. Škapin and
• Polona Umek

Beilstein J. Nanotechnol. 2015, 6, 831–844, doi:10.3762/bjnano.6.86

• Figure 6), which is reflected in the increase of specific surface area, i.e., by a factor of about 3 compared to TO-650. As expected, an additional calcination of CH-W and MW-W caused a slight decrease in the specific surface area of CH-W+TN and MW-W+TO. Optical band-gap features The band gap of the

Novel ZnO:Ag nanocomposites induce significant oxidative stress in human fibroblast malignant melanoma (Ht144) cells

• Syeda Arooj,
• Samina Nazir,
• Akhtar Nadhman,
• Nafees Ahmad,
• Bakhtiar Muhammad,
• Ishaq Ahmad,
• Kehkashan Mazhar and
• Rashda Abbasi

Beilstein J. Nanotechnol. 2015, 6, 570–582, doi:10.3762/bjnano.6.59

• formulations of ZnO:Ag (1, 3, 5, 10, 20 and 30% Ag) were synthesized by a simple co-precipitation method and characterized by powder X-ray diffraction, scanning electron microscopy, Rutherford back scattering and diffuse reflectance spectroscopy for their structure, morphology, composition and optical band gap

Structural, optical, opto-thermal and thermal properties of ZnS–PVA nanofluids synthesized through a radiolytic approach

• Alireza Kharazmi,
• Nastaran Faraji,
• Roslina Mat Hussin,
• Elias Saion,
• W. Mahmood Mat Yunus and
• Kasra Behzad

Beilstein J. Nanotechnol. 2015, 6, 529–536, doi:10.3762/bjnano.6.55

• concentration in agreement with the FTIR results. The optical band gap energy of the ZnS NPs was estimated through the Tauc equation as follows [6]: where α is the absorption coefficient, hν is the photon energy of the incident light, Eg is the band gap energy, B is a constant and n depends on the type of

• . Illustration of hydrolyzed PVA. TEM images of ZnS NPs within PVA matrix at (a) 10 kGy, (b) 30 kGy and (c) 50 kGy dose. XRD pattern of ZnS NPs mediated by PVA from 10 to 50 kGy doses. Optical spectra of ZnS–PVA nanofluids synthesized at various doses. Optical band gap energy of ZnS NPs after irradiation with

Synthesis of boron nitride nanotubes and their applications

• Saban Kalay,
• Zehra Yilmaz,
• Ozlem Sen,
• Melis Emanet,
• Emine Kazanc and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2015, 6, 84–102, doi:10.3762/bjnano.6.9

• and optical band gap properties was evaluated [91]. Two intense blue emission peaks at ~480 nm and ~365 nm were observed upon encapsulation of BNNTs with Ni. The time-resolved photoluminescence spectroscopy (TRPL) provided a photoluminescence spectrum with a bi-exponential decay of 280 ps. It was

Growth evolution and phase transition from chalcocite to digenite in nanocrystalline copper sulfide: Morphological, optical and electrical properties

• Priscilla Vasthi Quintana-Ramirez,
• Ma. Concepción Arenas-Arrocena,
• José Santos-Cruz,
• Marina Vega-González,
• Omar Martínez-Alvarez,
• Víctor Manuel Castaño-Meneses,
• Laura Susana Acosta-Torres and
• Javier de la Fuente-Hernández

Beilstein J. Nanotechnol. 2014, 5, 1542–1552, doi:10.3762/bjnano.5.166

• structure. All CuxS products could be promising for optoelectronic applications. Keywords: abundant materials in the crust of Earth; electrical resistance; nanocrystals; nanodisks; non-toxic semiconductors; optical band gap; phase transition; photocurrent; Introduction Metallic chalcogenides based on

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

• pattern of (A) pristine and (B) light-soaked, optical band gap determination based on Tauc’s plot, (αhν)2 vs hν plot of (C) pristine (D) light-soaked chalcopyrite nanocrystals of (a) CISe, (b) CIGSe and (c) CZTSe. UV-lamp exposed photographs of polymer P3HT, P3HT:CISe, P3HT:CIGSe and P3HT:CZTSe

Study of mesoporous CdS-quantum-dot-sensitized TiO₂ films by using X-ray photoelectron spectroscopy and AFM

• Mohamed N. Ghazzal,
• Robert Wojcieszak,
• Gijo Raj and
• Eric M. Gaigneaux

Beilstein J. Nanotechnol. 2014, 5, 68–76, doi:10.3762/bjnano.5.6

• between the optical band gap and the average particle size of CdS made by a different number of deposition cycles is shown in Figure 6c. As deduced from the band-gap and particle-size correlation curves, the smaller the particle size, the larger the band gap. This clearly demonstrates the quantum

• confinement characteristics of the CdS nanoparticles. The dependence of the optical band gap on the particle size observed in this study is consistent with previously reported data [12]. Conclusion This article has placed emphasis on the formation of the CdS particles on TiO2 films and characterizes those by

Synthesis of indium oxi-sulfide films by atomic layer deposition: The essential role of plasma enhancement

• Cathy Bugot,
• Nathanaëlle Schneider,
• Daniel Lincot and
• Frédérique Donsanti

Beilstein J. Nanotechnol. 2013, 4, 750–757, doi:10.3762/bjnano.4.85

• successfully grown by using O2 plasma as oxygen source at a deposition temperature of T = 160 °C, because of an exchange reaction between S and O atoms. By adjusting the number of In2O3 growth cycles in relation to the number of In2S3 growth cycles, the optical band gap of the resulting thin films could be

• chemistry, which is usually too sensitive for a direct deposition of the window layers. However, because of the toxicity of cadmium and the low optical band gap of CdS (2.4 eV [3]) that limits the light conversion of CIGS in the UV range of the solar spectrum, alternative materials have been developed. Most

• ]. Oxygen-doping of In2S3 films is known to increase their optical band gap value [6][17][18]. Indeed, by O-doping of In2S3 films deposited by thermal evaporation, Barreau et al. could increase the optical band gap value of In2S3 thin films from 2.1 to 2.9 eV [17]. In the same way, by using the spray

Photocatalytic antibacterial performance of TiO₂ and Ag-doped TiO₂ against S. aureus. P. aeruginosa and E. coli

• Kiran Gupta,
• R. P. Singh,
• Ashutosh Pandey and
• Anjana Pandey

Beilstein J. Nanotechnol. 2013, 4, 345–351, doi:10.3762/bjnano.4.40

• indirect optical band gap of 3.2 eV, while the rutile phase has a direct band gap of 3.06 eV and an indirect one of 3.10 eV [7]. However, crude nanoparticles are amorphous in nature, with decreased surface area, and show a fast recombination rate of electrons and holes. Finally the antibacterial activity

• absorption coeffiecient α to zero for indirect-band-gap nanoparticles. The obtained band-gap energy for indirect allowed transitions is in good harmony with the previously reported values [18]. The optical band-gap energies decrease with the doping of silver ions, which allow the delay in recombination rate

Effect of deposition temperature on the structural and optical properties of chemically prepared nanocrystalline lead selenide thin films

• Anayara Begum,
• Amir Hussain and
• Atowar Rahman

Beilstein J. Nanotechnol. 2012, 3, 438–443, doi:10.3762/bjnano.3.50

• crystallite size. The optical absorption spectra of the nanocrystalline PbSe films showed a blue shift, and the optical band gap (Eg) was found to increase from 1.96 to 2.10 eV with the decrease in crystallite size. Keywords: chemical bath deposition; lattice parameter; lead selenide; Nelson–Riley plot

• defects. The (αhν)2 versus (hν) plots of PbSe thin films are linear over a wide range of photon energies, as shown in Figure 7b. This indicates the presence of a direct optical band gap in the as-prepared PbSe thin films [23]. The optical band gap of these films was obtained by extrapolating the linear

• an increase in the band gap with a decrease in crystallite size (the structural parameters and band-gap energies are also summarized in Table 1). Clearly, the observed values of Eg are higher than the value of the bulk optical band gap of PbSe [0.27 eV] [1] due to quantum confinement in the

Junction formation of Cu₃BiS₃ investigated by Kelvin probe force microscopy and surface photovoltage measurements

• Fredy Mesa,
• William Chamorro,
• William Vallejo,
• Robert Baier,
• Thomas Dittrich,
• Alexander Grimm,
• Martha C. Lux-Steiner and
• Sascha Sadewasser

Beilstein J. Nanotechnol. 2012, 3, 277–284, doi:10.3762/bjnano.3.31

• ) and Cu3BiS3/In2S3 (b) samples. The x-signal begins at photon energies significantly below the optical band gap of Cu3BiS3. For Cu3BiS3 the in-phase PV signal is initially positive and increases to about 13 µV with increasing photon energy. Before a strong increase of the signal up to 114 µV at photon

Investigation on structural, thermal, optical and sensing properties of meta-stable hexagonal MoO₃ nanocrystals of one dimensional structure

• Angamuthuraj Chithambararaj and
• Arumugam Chandra Bose

Beilstein J. Nanotechnol. 2011, 2, 585–592, doi:10.3762/bjnano.2.62

• characteristic peaks of molybdenum and oxygen. Thermogravimetric (TG) analysis on metastable MoO3 revealed that the hexagonal phase was stable up to 430 °C and above this temperature complete transformation into a highly stable orthorhombic phase was achieved. The optical band gap energy was estimated from the

• for indirect transition. The indirect optical band gap energy is determined by extrapolating the linear portion of the plots of (F(R∞)hν)1/2 versus (hν) shown as an inset in Figure 9. The estimated energy band gap value is about 2.99 eV and is considerably higher than that of the bulk (2.95 eV). This

• -dimensional structure of h-MoO3. HRTEM image of an as-synthesized h-MoO3 nanorod and their electron diffraction pattern (inset). EELS spectrum of resultant h-MoO3. TG/DTG and DTA curve of h-MoO3. DRS spectrum of h-MoO3 (Inset: optical band gap energy of h-MoO3). Spectral response of h-MoO3 for varying