Bombyx mori silk/titania/gold hybrid materials for photocatalytic water splitting: combining renewable raw materials with clean fuels

• Stefanie Krüger,
• Michael Schwarze,
• Otto Baumann,
• Christina Günter,
• Michael Bruns,
• Christian Kübel,
• Dorothée Vinga Szabó,
• Rafael Meinusch,
• Verónica de Zea Bermudez and
• Andreas Taubert

Beilstein J. Nanotechnol. 2018, 9, 187–204, doi:10.3762/bjnano.9.21

• to a wealth of studies on photocatalytic water splitting [6][7][8][9][10]. To be successful, the water splitting catalyst needs to have a certain set of properties. Most prominently, it should have a bandgap of at least 1.23 eV to provide the energy needed to split water. However, the bandgap should

• not exceed ca. 3 eV to most efficiently use the visible spectral range of the sunlight [6]. As a result, numerous water-splitting catalysts with various efficiencies have been reported [6][7][8][11][12][13]. Because of its bandgap of 3.0–3.2 eV (depending on the crystal structure and particle size [14

• bandgap of the TiO2 semiconductors [21]. Gallo et al. used amorphous TiO2 doped with Au and/or platinum (Pt) NPs to split water under ultraviolet (UV)-A light and simulated sunlight. Best results with 1.6 mmol/(h·g) of H2 production were obtained with Au0.5Pt0.5/TiO2 catalysts [22]. Chen et al. used

Design of photonic microcavities in hexagonal boron nitride

• Sejeong Kim,
• Milos Toth and
• Igor Aharonovich

Beilstein J. Nanotechnol. 2018, 9, 102–108, doi:10.3762/bjnano.9.12

• attractive candidate for a monolithic cavity system. In particular, hBN has a wide bandgap of ≈6 eV which makes it transparent in the visible spectral range that contains the zero phonon lines (ZPLs) of a range of ultra-bright emitters [21]. Furthermore, hBN has properties which are desirable for micro

• full photonic bandgap between the first and the second lowest photonic energy bands even when the effective index contrast is low [31]. The combination of a high Q-factor and a low refractive index enables a broad range of applications such as flexible photonic crystal devices and high figure of merit

Review on optofluidic microreactors for artificial photosynthesis

• Xiaowen Huang,
• Jianchun Wang,
• Tenghao Li,
• Jianmei Wang,
• Min Xu,
• Weixing Yu,
• Abdel El Abed and
• Xuming Zhang

Beilstein J. Nanotechnol. 2018, 9, 30–41, doi:10.3762/bjnano.9.5

• energy could be offered by external light. In principle, a semiconductor photocatalyst (e.g., TiO2, C3N4) absorbs the appropriate photon (hν ≥ E0, where E0 is the bandgap of the semiconductor photocatalyst) to excite an electron in the conduction band, leaving a hole in the valence band. The electron

Thermo- and electro-optical properties of photonic liquid crystal fibers doped with gold nanoparticles

• Agata Siarkowska,
• Miłosz Chychłowski,
• Daniel Budaszewski,
• Bartłomiej Jankiewicz,
• Bartosz Bartosewicz and
• Tomasz R. Woliński

Beilstein J. Nanotechnol. 2017, 8, 2790–2801, doi:10.3762/bjnano.8.278

• PLCF with a Ti-doped 5CB nematic LC has been recently reported in [18], where a noticeable difference in both the orientation of the molecules and the propagation spectra of the PLCF was observed. The light was guided according to a mechanism known as the photonic bandgap (PBG) effect, in which only

Facile synthesis of silver/silver thiocyanate (Ag@AgSCN) plasmonic nanostructures with enhanced photocatalytic performance

• Xinfu Zhao,
• Dairong Chen,
• Abdul Qayum,
• Bo Chen and
• Xiuling Jiao

Beilstein J. Nanotechnol. 2017, 8, 2781–2789, doi:10.3762/bjnano.8.277

• catalyst due to its wide bandgap of 3.2 eV, which limits its practical application. Therefore, the development of new photocatalysts with visible-light catalytic performance, high surface active sites and long life of separated electron and hole pairs, has become a hot research topic in recent years. Ag

• importance. As one of the Ag-containing semiconductor materials, AgSCN exhibits superior stability under irradiation [23][24]. The relatively large bandgap of AgSCN (3.4 eV) makes it only ultraviolet light active, largely limiting the wide utilization of the solar light energy spectrum. The addition of Ag on

• absorption of Ag@AgSCN in both the UV and visible region, which is beneficial for application as a visible-light catalyst. The bandgap of AgSCN can be determined according to the Kubelka–Munk equation, which is estimated as 3.4 eV for sample M0 (Figure 2b), and the valence band value of 1.12 eV is obtained

CdSe nanorod/TiO₂ nanoparticle heterojunctions with enhanced solar- and visible-light photocatalytic activity

• Fakher Laatar,
• Hatem Moussa,
• Halima Alem,
• Lavinia Balan,
• Emilien Girot,
• Ghouti Medjahdi,
• Hatem Ezzaouia and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2017, 8, 2741–2752, doi:10.3762/bjnano.8.273

• the narrow bandgap of CdSe NRs serves to increase the photoresponse of CdSe/TiO2 composites until ≈725 nm. The CdSe (2 wt %)/TiO2 composite exhibits the highest photocatalytic activity for the degradation of rhodamine B in aqueous solution under simulated sunlight or visible light irradiation. The

• suffers from two main drawbacks. First, due to its wide bandgap (Eg = 3.2 and 3.0 eV for anatase and rutile, respectively), TiO2 can only be activated by light with a wavelength of less than 390 nm to trigger the electron–hole separation. Second, TiO2 exhibits a low quantum efficiency due to the fast

• recombination of photogenerated charge carriers (electrons and holes). To address these problems, a number of studies have been devoted to the improvement of light absorption and charge separation by hybridizing TiO2 with narrow bandgap semiconductors, doping with metal or nonmetal elements, association with

Ab initio study of adsorption and diffusion of lithium on transition metal dichalcogenide monolayers

• Xiaoli Sun and
• Zhiguo Wang

Beilstein J. Nanotechnol. 2017, 8, 2711–2718, doi:10.3762/bjnano.8.270

• in the 1T or 1T' phase, but only a few of them were stable in both 2H/1T or 2H/1T' phases. The results show that lithium is energetically favourable for adsorption on MX2 monolayers, which can be semiconductors with a narrow bandgap and metallic materials. Lithium cannot be adsorbed onto 2H-WS2 and

• group VI for a given element M. The variation can be explained by the increasing atomic radius of elements X from S to Te. The band structures of MX2 monolayers in the stable phase are shown in Figure 2. The MX2 monolayers can be semiconducting with a direct and indirect bandgap or metallic materials

• , 1T-ZrX2 and 1T-HfX2 show semiconducting and metallic behaviour with X = S/Se and X = Te, respectively. 1T'-VTe2 and 1T'-MoTe2 show metallic behaviour and 1T'-WTe2 has a narrow bandgap of 0.50 eV. The obtained bandgap values are close to those previously reported for TiS2 [32], CrTe2 [40], TiX2 [32

Enhanced photoelectrochemical water splitting performance using morphology-controlled BiVO₄ with W doping

• Xin Zhao and
• Zhong Chen

Beilstein J. Nanotechnol. 2017, 8, 2640–2647, doi:10.3762/bjnano.8.264

• . Photoelectrochemical (PEC) water splitting generates hydrogen through chemical reactions assisted by photo-generated electrons and holes in semiconductor materials [1][2][3]. An ideal semiconductor for PEC water splitting requires a small bandgap to capture enough solar light, a high conversion efficiency, a good

• developing photoanode materials and optimizing their performance. Monoclinic BiVO4 is one of the most promising photoanode materials for PEC water splitting, as it meets most of the requirements. It has a theoretical conversion efficiency of 9.1% with a bandgap of 2.4 eV. Moreover, it also possesses a

Optical contrast and refractive index of natural van der Waals heterostructure nanosheets of franckeite

• Patricia Gant,
• Foad Ghasemi,
• David Maeso,
• Carmen Munuera,
• Elena López-Elvira,
• Riccardo Frisenda,
• David Pérez De Lara,
• Gabino Rubio-Bollinger,
• Mar Garcia-Hernandez and
• Andres Castellanos-Gomez

Beilstein J. Nanotechnol. 2017, 8, 2357–2362, doi:10.3762/bjnano.8.235

• bandgap (below 0.7 eV) and p-type doping, and that they are very resilient upon atmospheric exposure. These characteristics makes franckeite an excellent alternative to black phosphorus which tends to degrade quickly upon air exposure [20][21][22][23]. Here we study the thickness dependence of the optical

Substrate and Mg doping effects in GaAs nanowires

• Perumal Kannappan,
• Nabiha Ben Sedrine,
• Jennifer P. Teixeira,
• Maria R. Soares,
• Bruno P. Falcão,
• Maria R. Correia,
• Nestor Cifuentes,
• Emilson R. Viana,
• Marcus V. B. Moreira,
• Geraldo M. Ribeiro,
• Alfredo G. de Oliveira,
• Juan C. González and
• Joaquim P. Leitão

Beilstein J. Nanotechnol. 2017, 8, 2126–2138, doi:10.3762/bjnano.8.212

• for application in solar cells owing to their high absorption, direct bandgap, high carrier mobility and well-developed synthesis techniques [5][6][7][8][9]. Among the group III–V semiconductors, GaAs is one of the most intensively studied materials and has a suitable bandgap energy value for solar

• phase is favored [2]. In general, GaAs nanowires show a polytypic structure along the gowth axis that is characterized by the occurrence of a mixture of WZ and ZB phases [12][13][14]. This fact creates an unintentional bandgap that critically influences the optical and electrical properties of the

• level structure of the nanowires, a detailed investigation on the temperature-dependent PL is required. Before the presentation of the results, we will mention briefly the common temperature dependence of the bandgap in a semiconductor. As the temperature increases, the thermal expansion coefficient of

Optical techniques for cervical neoplasia detection

• Tatiana Novikova

Beilstein J. Nanotechnol. 2017, 8, 1844–1862, doi:10.3762/bjnano.8.186

• fluorophores for cellular imaging [57][83][85][90][91][92][93]. The unique optical properties of semiconductor quantum dots including quantum confinement effect, wide absorption spectrum (i.e., broad excitation band), and narrow emission spectrum (i.e., tunable fluorescence emission via QD bandgap engineering

Two-dimensional silicon and carbon monochalcogenides with the structure of phosphorene

• Dario Rocca,
• Ali Abboud,
• Ganapathy Vaitheeswaran and
• Sébastien Lebègue

Beilstein J. Nanotechnol. 2017, 8, 1338–1344, doi:10.3762/bjnano.8.135

• these monolayers were determined using density functional theory. By using accurate hybrid functionals it was found that these materials are semiconductors and span a broad range of bandgap values and types. Similarly to phosphorene, the computed effective masses point to a strong in-plane anisotropy of

• electronic structure that are markedly different from those of graphene, with, for instance, the existence of a finite bandgap in the band structure [5]. One of the latest newcomers in the family of two-dimensional materials is phosphorene [6][7][8][9], which corresponds to a single layer of black phosphorus

• , accordingly, phosphorene has an indirect gap at the PBE level of theory. However, the gap and the direct gap in Γ differs by less than 10 meV and for this reason phosphorene is commonly considered a direct bandgap semiconductor [8][35]. In Table 1 the HSE gap is denoted as direct. Very likely the difference

Enhanced catalytic activity without the use of an external light source using microwave-synthesized CuO nanopetals

• Govinda Lakhotiya,
• Sonal Bajaj,
• Arpan Kumar Nayak,
• Debabrata Pradhan,
• Pradip Tekade and
• Abhimanyu Rana

Beilstein J. Nanotechnol. 2017, 8, 1167–1173, doi:10.3762/bjnano.8.118

• absorption onset was estimated from the Tauc’s plot as shown in Figure 2b. The band gap of CuO nanopetals was calculated by extrapolating the linear part of the plot of (αhν)1/2 vs hν and is found to be ≈1.85 eV as shown in Figure 2b. This is different from the bulk bandgap of CuO, which is 1.24 eV [10

Growth, structure and stability of sputter-deposited MoS₂ thin films

• Reinhard Kaindl,
• Bernhard C. Bayer,
• Roland Resel,
• Thomas Müller,
• Viera Skakalova,
• Gerlinde Habler,
• Rainer Abart,
• Alexey S. Cherevan,
• Dominik Eder,
• Maxime Blatter,
• Fabian Fischer,
• Jannik C. Meyer,
• Dmitry K. Polyushkin and
• Wolfgang Waldhauser

Beilstein J. Nanotechnol. 2017, 8, 1115–1126, doi:10.3762/bjnano.8.113

• , recent studies demonstrated that MoS2 is stable in its few- and single-layer form [7][8] (similar to graphene) and has intriguing electrical and optical properties [9]. Bulk MoS2 is usually of 2H type and a n-type semiconductor with an indirect bandgap of ≈1.3 eV [10], whereas 2H MoS2 monolayers were

• found to have a direct bandgap of ≈1.8 eV [8]. Relatively high mechanical flexibility, good optical transmittance, high current on/off ratios in field effect transistor (FET) geometries and reasonably good field effect mobilities make atomically thin MoS2 layers a promising candidate for flexible and

ZnO nanoparticles sensitized by CuInZn_xS_2+x quantum dots as highly efficient solar light driven photocatalysts

• Florian Donat,
• Serge Corbel,
• Halima Alem,
• Steve Pontvianne,
• Lavinia Balan,
• Ghouti Medjahdi and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2017, 8, 1080–1093, doi:10.3762/bjnano.8.110

• bandgap (≈3.2–3.3 eV) restricts light activation to the UV range (which accounts for only ≈4% of the solar spectrum) for the generation of the charge carriers responsible for the surface redox reactions. To improve the efficient use of solar light, visible-light-responsive photocatalysts should be

• developed. This can be achieved by combining TiO2 or ZnO with narrow bandgap semiconductors such as quantum dots (QDs), where generally cadmium or lead chalcogenides are applied [9]. Due to the close interfacial contact between the semiconductors, the electronic structures of ZnO or TiO2 are strongly

• CIS core QDs using the Zn(OAc)2-OA complex [23]. The obtained ZCIS QDs absorb light until ca. 700 nm and their PL maximum is located at ca. 620 nm (Supporting Information File 1, Figure S1). The PL quantum yield of these red-emitting dots is 50% in toluene and their bandgap, estimated through the

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

Photocatalysis applications of some hybrid polymeric composites incorporating TiO₂ nanoparticles and their combinations with SiO₂/Fe₂O₃

• Andreea Laura Chibac,
• Tinca Buruiana,
• Violeta Melinte and
• Emil C. Buruiana

Beilstein J. Nanotechnol. 2017, 8, 272–286, doi:10.3762/bjnano.8.30

• , they are active only in UV light (<4% of sunlight) owing to their wide bandgap (3.2 eV), which absorbs photons with wavelengths shorter than 400 nm. Also, TiO2 nanoparticles (NPs) have a low adsorption capacity for hydrophobic molecules, and if they are used for water treatment, severe problems during

Impact of contact resistance on the electrical properties of MoS₂ transistors at practical operating temperatures

• Filippo Giannazzo,
• Gabriele Fisichella,
• Aurora Piazza,
• Salvatore Di Franco,
• Giuseppe Greco,
• Simonpietro Agnello and
• Fabrizio Roccaforte

Beilstein J. Nanotechnol. 2017, 8, 254–263, doi:10.3762/bjnano.8.28

• layers (where M = Mo, W, etc., i.e., a transition metal, and X = S, Se, Te, i.e., a chalcogen atom). Among the large number of existing layered materials [1], TMDs are currently attracting increasing scientific interest due to some distinct properties, such as the presence of a sizable bandgap in their

• band structure. As an example, MoS2 (the most studied among TMDs due to its high abundance in nature and relatively high stability under ambient conditions) exhibits an indirect bandgap of ≈1.3 eV in the case of few layers and bulk material and a direct bandgap of ≈1.8 eV in the case of a single layer

Monolayer graphene/SiC Schottky barrier diodes with improved barrier height uniformity as a sensing platform for the detection of heavy metals

• Ivan Shtepliuk,
• Jens Eriksson,
• Volodymyr Khranovskyy,
• Tihomir Iakimov,
• Anita Lloyd Spetz and
• Rositsa Yakimova

Beilstein J. Nanotechnol. 2016, 7, 1800–1814, doi:10.3762/bjnano.7.173

• metals. The key issue is that the heavy metal adsorption leads to band-structure reorganization and changing of the energy gap of the graphene clusters (as was discussed before). Bandgap opening may also be expected in epitaxial monolayer graphene on SiC due to the interaction with heavy metals. It is

Active and fast charge-state switching of single NV centres in diamond by in-plane Al-Schottky junctions

• Christoph Schreyvogel,
• Vladimir Polyakov,
• Sina Burk,
• Helmut Fedder,
• Andrej Denisenko,
• Felipe Fávaro de Oliveira,
• Ralf Wunderlich,
• Jan Meijer,
• Verena Zuerbig,
• Jörg Wrachtrup and
• Christoph E. Nebel

Beilstein J. Nanotechnol. 2016, 7, 1727–1735, doi:10.3762/bjnano.7.165

• a single NV centre, we have to control the position of the Fermi-level relative to charge transition levels NV+/0 and NV0/− of the centre within the bandgap of diamond. The charge transition level of a defect centre is defined as a level at which the centre takes up or loses an electron when the

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

• chemicals occurs. The aerosol is produced using an ultrasonic oscillator in a bath of precursor solution and guided by compressed air. The use of the ultrasonic CSP resulted in the growth of homogeneous and well-adhered layers that consist of submicron crystals of single-phase Sb2S3 with a bandgap of 1.6 eV

• (0.056 nm·cycle−1, 33.5 s·cycle−1) prior to annealing in H2S atmosphere [5]. Similarly, the conventional CBD requires hours of processing time prior to the annealing procedure [46][47], yielding growth speeds around 0.003 nm·s−1 for Sb2S3 films [47]. The bandgap (Eg) of Sb2S3 was 1.6 eV irrespective of

• the number of deposition cycles used when grown using spray of 1:6 solutions onto a glass/ITO/TiO2 stack (Figure 5). The bandgap of the Sb2S3 was calculated using the spectra of the absorption coefficient of the glass/ITO/TiO2/Sb2S3 layer stacks (Figure 4B). The bandgaps obtained are in accordance

Enhanced detection of nitrogen dioxide via combined heating and pulsed UV operation of indium oxide nano-octahedra

• Oriol Gonzalez,
• Sergio Roso,
• Xavier Vilanova and
• Eduard Llobet

Beilstein J. Nanotechnol. 2016, 7, 1507–1518, doi:10.3762/bjnano.7.144

• slow dynamics. The decrease in sensor resistance can be explained by different mechanisms. Electrons in the valence band of indium oxide absorb energy from the UV light to jump to the conduction band. The bandgap of cubic indium oxide is about 3 eV and the 325 nm UV diode employed (3.8 eV) should allow

Nanostructured germanium deposited on heated substrates with enhanced photoelectric properties

• Ionel Stavarache,
• Valentin Adrian Maraloiu,
• Petronela Prepelita and
• Gheorghe Iordache

Beilstein J. Nanotechnol. 2016, 7, 1492–1500, doi:10.3762/bjnano.7.142

• to the indirect bandgap issue of Ge-based materials are partially overcome, but the difficulty of controlling size and shape of the nanoparticles still remains. New approaches for fine-tuning the size and shape of nanoparticles would facilitate the understanding of their quantum confinement behavior

A composite structure based on reduced graphene oxide and metal oxide nanomaterials for chemical sensors

• Vardan Galstyan,
• Elisabetta Comini,
• Iskandar Kholmanov,
• Andrea Ponzoni,
• Veronica Sberveglieri,
• Nicola Poli,
• Guido Faglia and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2016, 7, 1421–1427, doi:10.3762/bjnano.7.133

• consumption [7][8]. Metal oxide sensors can detect ethanol and acetone only at high operating temperatures (≥300 °C) [7][9][10]. ZnO is a extensively studied and inspiring material due to its unique properties, namely the wide bandgap and large exciton binding energy [11]. Most of the literature is focused on

Electric field induced structural colour tuning of a silver/titanium dioxide nanoparticle one-dimensional photonic crystal

• Eduardo Aluicio-Sarduy,
• Simone Callegari,
• Diana Gisell Figueroa del Valle,
• Andrea Desii,
• Ilka Kriegel and
• Francesco Scotognella

Beilstein J. Nanotechnol. 2016, 7, 1404–1410, doi:10.3762/bjnano.7.131

• Figure 2, where the transmission spectrum of the photonic crystal is reported as a function of the applied voltage. The transmission is dominated by two strong bands at around 480 nm and 620 nm, ascribed to the plasmonic resonances of the silver nanoparticles and the photonic bandgap, respectively. We

• want to emphasize the fundamentally different nature of the two resonances observed in our device, namely the plasmonic resonance of the silver nanoparticle layer and that of the photonic bandgap. The pump–probe measurement in Figure 3a shows the transmission spectra of the transient absorption

• as given in [28] and two artificially increased carrier densities. Similar to the experimental results, the calculated transmission spectra show an intense band in the UV/blue region ascribed to the plasmon resonance of the silver layer and a second band corresponding to the photonic bandgap. Note