TiO₂ immobilized on 2D mordenite: effect of hydrolysis conditions on structural, textural, and optical characteristics of the nanocomposites

• Marina G. Shelyapina,
• Rosario Isidro Yocupicio-Gaxiola,
• Gleb A. Valkovsky and
• Vitalii Petranovskii

Beilstein J. Nanotechnol. 2025, 16, 128–140, doi:10.3762/bjnano.16.12

• -axis of the linear fit of the Tauc plot. As one can see from Figure 7b, the Eg values for the studied TiO2/2D mordenite nanocomposites are sensitive to the hydrolysis medium. The samples obtained by hydrolysis in water exhibit Eg values of about 3.22 eV, which is close to the value of bulk anatase [45

Mn-doped ZnO nanopowders prepared by sol–gel and microwave-assisted sol–gel methods and their photocatalytic properties

• Cristina Maria Vlăduț,
• Crina Anastasescu,
• Silviu Preda,
• Oana Catalina Mocioiu,
• Simona Petrescu,
• Jeanina Pandele-Cusu,
• Dana Culita,
• Veronica Bratan,
• Ioan Balint and
• Maria Zaharescu

Beilstein J. Nanotechnol. 2024, 15, 1283–1296, doi:10.3762/bjnano.15.104

• determined using the Tauc plot method, considering direct transitions. The method consists in the extrapolation of the linear region of the rising part of the curve (αhν)1/η as a function of hν to zero to get the bandgap (where α is the Kubelka–Munk function, hν is the energy of the photons, and η has the

• samples: SG (left) and MW (right). Comparative UV–vis spectra of SG and MW; the inset illustrates the Tauc plot for SG and MW samples. Photoluminescence spectra of the powders suspended in water (SG and MW) collected for λexc = 270 nm. Quenching of catalyst photoluminescence with increasing oxalic acid

Isolation of cubic Si₃P₄ in the form of nanocrystals

• Polina K. Nikiforova,
• Sergei S. Bubenov,
• Vadim B. Platonov,
• Andrey S. Kumskov,
• Nikolay N. Kononov,
• Tatyana A. Kuznetsova and
• Sergey G. Dorofeev

Beilstein J. Nanotechnol. 2023, 14, 971–979, doi:10.3762/bjnano.14.80

• agglomeration for at least a month. The synthesized samples were brown powders that formed brown sols in acetonitrile, quite similar in appearance to those of Si NPs. Upon examination of the UV–vis absorption spectra, a bandgap of 1.25 eV was established using Tauc plot (Figure 5). A simpler approach for a

• theoretical diffraction pattern of Si3P4; the vertical lines height is scaled to relative intensity of the respective maximum. Raman scattering spectra of (a) SP900, (b) SP670, and (c) SP550. IR spectra of (a) Si, (b) SP900, (c) SP670, and (d) SP400. Tauc plot of the optical absorption of a Si3P4 NPs sample

Titania nanoparticles for photocatalytic degradation of ethanol under simulated solar light

• Evghenii Goncearenco,
• Iuliana P. Morjan,
• Claudiu Teodor Fleaca,
• Florian Dumitrache,
• Elena Dutu,
• Monica Scarisoreanu,
• Valentin Serban Teodorescu,
• Alexandra Sandulescu,
• Crina Anastasescu and
• Ioan Balint

Beilstein J. Nanotechnol. 2023, 14, 616–630, doi:10.3762/bjnano.14.51

• direct and indirect transitions, which are related to the crystal structure. To distinguish these two types of transition, it is common to use the Tauc plot [55][56][57][58], where the absorbance coefficient is multiplied with the photon energy and plotted as an exponential function of the photon energy

LED-light-activated photocatalytic performance of metal-free carbon-modified hexagonal boron nitride towards degradation of methylene blue and phenol

• Nirmalendu S. Mishra and
• Pichiah Saravanan

Beilstein J. Nanotechnol. 2022, 13, 1380–1392, doi:10.3762/bjnano.13.114

• function by utilizing the Tauc plot mentioned in Equation 3. The obtained values were depicted in Figure 5a–e. The enhanced light absorption properties could be attributed to the grey/black colour of MBN and enhanced charge transfer attained due to the change in the electronic structure through the

• Tauc plot, (f) RI plot, and (g) LHE plot for the studied materials. (a) Nyquist plot for HBN and MBN-80, (b, c) MS-plot, (d) Wsc analysis for HBN and MBN-80, (e, f) OCPT, and (g) LSV plots for HBN and MBN-80. (a) Adsorption of MB and phenol at varied pH values. (b) The effect of pH variation on

Near-infrared photoactive Ag-Zn-Ga-S-Se quantum dots for high-performance quantum dot-sensitized solar cells

• Roopakala Kottayi,
• Ilangovan Veerappan and
• Ramadasse Sittaramane

Beilstein J. Nanotechnol. 2022, 13, 1337–1344, doi:10.3762/bjnano.13.110

• spectrum of colloidal AZGSSe QDs (Figure 4a) reveals a wide absorption range in the near-infrared (NIR) region. This confirms the NIR photoactive nature of the synthesized QDs. Figure 4b depicts the Tauc plot [30] of the synthesized QDs. From this, the bandgap energy of AZGSSe QDs was found to be 1.37 eV

• –vis–NIR absorption spectrum; (b) Tauc Plot; (c) PL emission; (d) PL decay spectrum of AZGSSe QDs. (a) HRTEM image and (b) EDX spectrum of AZGSSe QDs/TiO2 NFs. (a) UV–vis absorbance spectra; (b) PL decay spectra; (c) PL emission spectra of the AZGSSe/TiO2 NF-based photoanode. Nyquist plot of the

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

• 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

• Eg is the x-axis interception when linear fitting the absorption edge of the Tauc plot. As both the direct and the indirect electron transition in the brookite were reported, two transitions were considered in this work. Figure 2 shows the Tauc plot derived from the diffuse reflectance spectra of

• of the MB (≈665 nm) acquired by a UV–vis spectrophotometer. The diffuse reflectance spectra were measured in the wavelength range of 300–800 nm using a UV–vis spectrophotometer. The bandgap was determined by linear fitting the absorption edge of the Tauc plot of the absorption spectra. Structure

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

• the amorphous particles, until a grayish-black mixture of crystalline material without spherical, amorphous particles (≈18 h) was finally obtained. Optical characterization The optical properties of the materials were measured by reflectance spectroscopy and analyzed by applying the Tauc plot to

• amorphous materials can be divided into localized and delocalized states, forming a so-called mobility gap [46]. Initially, the Tauc plot (Equation 1) was used to calculate band gap values for amorphous materials, i.e., mobility gaps, with a transition factor γ equal to 2 [37]. Hence, an amorphous material

• et al., who evaluated the accuracy of the Tauc plot for 120 individual analyses of polycrystalline ZnO and found a deviation of about 0.03 eV [52]. XRD For XRD measurements, a minimum amount of 10 mg of dried particles was used. The samples were measured in a capillary in transmission geometry. Two

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

• ionized oxygen vacancies located either in volume or at the surface of the material. (b) PL spectra showing all possible defect centers, including non-paramagnetic ones. The defects emit visible light yielding a broad emission band [4]. (c) Tauc plot obtained from UV–vis reflectance measurements

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

• plot of the square root of the Kubelka–Munk function vs the photon energy (Tauc plot, Figure 6). The observed bandgap energy of 2.07 eV is considerably smaller than that of bulk BiFeO3 and comparable to those found in the literature for similarly sized particles [6][23][29][53]. However, we would like

• particles (b) particle size analysis (c) particles synthesized by a previously reported co-precipitation method, avg. size 20 nm (d) bulk material. Absorbance spectra and Tauc plot (inset) for 5.5 nm BiFeO3 nanoparticles. Photocatalytic degradation of RhB as a function of irradiation time under visible

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

• Tu and Tu with CTAB was calculated by using a Tauc plot. As shown in Figure 5b, the extrapolation of the linear part of the curve to the photon energy axis produces the optical energy gap. The energy gap of Ag2S NPs synthesized in Tu and Tu with CTAB was 1.5 and 2 eV, respectively. The energy gap was

Effect of Ag loading position on the photocatalytic performance of TiO₂ nanocolumn arrays

• Jinghan Xu,
• Yanqi Liu and
• Yan Zhao

Beilstein J. Nanotechnol. 2020, 11, 717–728, doi:10.3762/bjnano.11.59

• indirect bandgap semiconductor, since the grains are small and the energy levels are discrete: In Equation 1, h is Plank’s constant (6.626 × 10−34 J s), ν is the frequency of light, and Eg represents the bandgap energy. For the calculation of Eg by the Tauc plot absorbance the value of the absorption (Abs

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

• width of the bandgap can be determined from the study of fundamental (intrinsic) absorption in thin layers. We determined the optical width of the bandgap corresponding to the direct optical transitions, , by extrapolating the linear portion of the dependence (αhν)2 = f(hν) to (αhν)2 → 0. Using a Tauc

• plot, the bandgap width for the ITO films was determined to be between 3.17 eV and 3.67 eV (Figure 7). The values of the bandgap width corresponding to direct optical transitions, determined from these dependencies, are shown in Table 4. In agreement with other researchers [28][29] regarding ITO films

Hierarchical heterostructures of Bi₂MoO₆ microflowers decorated with Ag₂CO₃ nanoparticles for efficient visible-light-driven photocatalytic removal of toxic pollutants

• Shijie Li,
• Wei Jiang,
• Shiwei Hu,
• Yu Liu,
• Yanping Liu,
• Kaibing Xu and
• Jianshe Liu

Beilstein J. Nanotechnol. 2018, 9, 2297–2305, doi:10.3762/bjnano.9.214

• absorption of the Ag2CO3/Bi2MoO6 heterostructures was substantially improved owing through the introduction of Ag2CO3 nanoparticles. Ag/Ag2CO3/Bi2MoO6 [32], Ag2MoO4/Bi2MoO6 [22], and Ag2CO3/Bi2MoO6 heterostrutures are VLD photocatalysts. The band gap energy (Eg) can be estimated from the Tauc plot: (αhν) = A

Facile synthesis of ZnFe₂O₄ photocatalysts for decolourization of organic dyes under solar irradiation

• Arjun Behera,
• Debasmita Kandi,
• Sanjit Manohar Majhi,
• Satyabadi Martha and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 436–446, doi:10.3762/bjnano.9.42

• samples with different calcination temperatures. (a) FESEM image and (b) enlarged view of ZFO-500. (a) TEM image and (b) magnified TEM image of ZFO-500. (a) Diffuse reflectance spectra of ZFO samples with different calcinantion temperatures with ZFO-500 showing the highest absorbance; (b) Tauc plot of ZFO

High photocatalytic activity of Fe₂O₃/TiO₂ nanocomposites prepared by photodeposition for degradation of 2,4-dichlorophenoxyacetic acid

• Shu Chin Lee,
• Hendrik O. Lintang and
• Leny Yuliati

Beilstein J. Nanotechnol. 2017, 8, 915–926, doi:10.3762/bjnano.8.93

• additional absorption peak corresponding to the Fe species. The bandgap energy (Eg) of the unmodified TiO2 and the nanocomposites were studied by a Tauc plot, considering the indirect transition in anatase TiO2 [34]. The Tauc plot of the TiO2 (NT) and the Fe2O3/TiO2 (IM) nanocomposites was derived by

Investigation of the photocatalytic efficiency of tantalum alkoxy carboxylate-derived Ta₂O₅ nanoparticles in rhodamine B removal

• Subia Ambreen,
• Mohammad Danish,
• Narendra D. Pandey and
• Ashutosh Pandey

Beilstein J. Nanotechnol. 2017, 8, 604–613, doi:10.3762/bjnano.8.65

• nanoparticles display a characteristic absorbance onset at ca. 360 nm (Figure 5). The deviation in the absorbance of nanoparticles may be attributed to the disparity in crystallite size and surface morphologies. The band gap is calculated from the Tauc plot [21]. Band gap energy and particle size are in

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

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

• Jasco V-670 spectrophotometer equipped with an integrating sphere. The absorption coefficient was calculated as α = d−1·ln(T−1), where d is the layer thickness and T is the total transmittance, i.e. the sum of diffuse and specular transmittance. A Tauc plot was used to determine the bandgap of Sb2S3

• is around 3.3 eV. Tauc plot of the optical transmittance spectra of the glass/ITO/TiO2/Sb2S3 layer stack, using α from Figure 4B. The linear part of the absorption edge when extended to the x-axis at y = 0 is used to determine the bandgap of Sb2S3. Sb2S3 was grown for three, five, seven and nine

Photocurrent generation in carbon nanotube/cubic-phase HfO₂ nanoparticle hybrid nanocomposites

• Protima Rauwel,
• Augustinas Galeckas,
• Martin Salumaa,
• Frédérique Ducroquet and
• Erwan Rauwel

Beilstein J. Nanotechnol. 2016, 7, 1075–1085, doi:10.3762/bjnano.7.101

• ] and put alongside for comparison in Figure 2. The absorption thresholds marked by the dashed lines in the Tauc plot in Figure 2b are consistent with the reported bandgap energies for hafnia (theoretical 4.9–5.7 eV and experimental 5–6 eV [14][42]) as well as with defect-related absorption showing up

Influence of wide band gap oxide substrates on the photoelectrochemical properties and structural disorder of CdS nanoparticles grown by the successive ionic layer adsorption and reaction (SILAR) method

• Mikalai V. Malashchonak,
• Alexander V. Mazanik,
• Olga V. Korolik,
• Еugene А. Streltsov and
• Anatoly I. Kulak

Beilstein J. Nanotechnol. 2015, 6, 2252–2262, doi:10.3762/bjnano.6.231

• significantly depends on the WBGO substrate used. The amount of deposited CdS has a significant impact on the shape of the photocurrent spectra of the heterostructures. This is characterized by a red shift of the photocurrent edge with increasing N (Figure 2a–c). The Tauc plot for direct optical transitions

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

• is clear, that the deficiencies of copper generate a displacement or shift of the optical absorption, which is consistent to the transition of the phases. The energy band gaps of the samples were computed by the Tauc plot for direct transition (Figure 5). The indirect plot (inset) did not present a

Microstructural and plasmonic modifications in Ag–TiO₂ and Au–TiO₂ nanocomposites through ion beam irradiation

• Venkata Sai Kiran Chakravadhanula,
• Yogendra Kumar Mishra,
• Venkata Girish Kotnur,
• Devesh Kumar Avasthi,
• Thomas Strunskus,
• Vladimir Zaporotchenko,
• Dietmar Fink,
• Lorenz Kienle and
• Franz Faupel

Beilstein J. Nanotechnol. 2014, 5, 1419–1431, doi:10.3762/bjnano.5.154

• wavelengths, which indicates an improvement in crystallinity of the matrix. From Tauc plot analyses for both nanocomposites, a shift of ca. 0.1 eV in the band-edge energy of TiO2 (between pristine and 1 × 1013 ions/cm2) is observed, which also confirms the structural changes in the TiO2 matrix. The red shift

Characterization and photocatalytic study of tantalum oxide nanoparticles prepared by the hydrolysis of tantalum oxo-ethoxide Ta₈(μ₃-O)₂(μ-O)₈(μ-OEt)₆(OEt)₁₄

• Subia Ambreen,
• N D Pandey,
• Peter Mayer and
• Ashutosh Pandey

Beilstein J. Nanotechnol. 2014, 5, 1082–1090, doi:10.3762/bjnano.5.121

• characterized by various techniques such as TGA-DTA-DSC, UV–vis DRS, XRD, SEM, TEM, particle size analyzer (DLS) and the Brunauer–Emmett–Teller (BET) method. The band gap of the particles was calculated by using the Tauc plot. The photocatalytic activity of Ta2O5 nanoparticles was tested by the degradation of

• the organic dye rhodamine B. Keywords: bandgap; tantalum-oxo-ethoxide; Tauc plot; tantalum pentoxide (Ta2O5); Introduction Metal alkoxides, being excellent precursors in the sol–gel process for preparation of metal oxides have attained huge attention of researchers. Several attempts have been made

• material, E is the photon energy, Eg is the band gap energy and n is a constant of different values, 1/2, 3/2, 2 and 3, depending on the type of electronic transition, i.e., permitted/prohibited-direct or indirect transition. The band gap is calculated from a Tauc plot [27][28][29][30]. The band gap of the

Mesoporous cerium oxide nanospheres for the visible-light driven photocatalytic degradation of dyes

• Subas K. Muduli,
• Songling Wang,
• Shi Chen,
• Chin Fan Ng,
• Cheng Hon Alfred Huan,
• Tze Chien Sum and
• Han Sen Soo

Beilstein J. Nanotechnol. 2014, 5, 517–523, doi:10.3762/bjnano.5.60

• P25 TiO2 nanomaterials. The estimated band gap from the Tauc plot is approximately 2.7 eV (Figure 2b), which corresponds to an absorption edge in the blue region (460 nm). The reduced band gap compared to CeO2 can be attributed to the presence of oxygen vacancies, as previously reported [32]. The

• spectrum. (c) High-resolution XPS spectrum of mesoporous cerium oxide (black circles) with the overall fit (black) and the fits to Ce4+ (blue) and Ce3+ (red). (a) UV–vis diffuse reflectance spectra of cerium oxide nanospheres (black), 7 nm CeO2 (red) nanopowder, and P25 TiO2 (blue). (b) Tauc plot for