Photodetectors based on carbon nanotubes deposited by using a spray technique on semi-insulating gallium arsenide

• Domenico Melisi,
• Maria Angela Nitti,
• Marco Valentini,
• Antonio Valentini,
• Teresa Ligonzo,
• Giuseppe De Pascali and
• Marianna Ambrico

Beilstein J. Nanotechnol. 2014, 5, 1999–2006, doi:10.3762/bjnano.5.208

• deposition technique for depositing CNTs on silicon, starting from a powder, at low temperatures, without catalyst and an intermediate layer [7]. By using this spray technique, CNT films on silicon-based photodetectors were prepared, achieving quantum efficiency (QE) values in the visible light range

• . Specifically, a Thorlabs OSL1 white light source with optical fiber and a focusing lens were used to obtain a light spot on the photodetector while single wavelengths (400, 500, 600 and 700 nm) in the visible light range were selected by means of a filter set. For the UV characterization in the spectral range

• reported for SFS and DFS in Figure 5 and Figure 6 for the visible and the UV range, respectively. The higher QE of SFS with respect to DFS at lower wavelengths in the visible light range (Figure 5) can be attributed to the contribution to the photo-generated charges from the near-band-gap light absorption

A reproducible number-based sizing method for pigment-grade titanium dioxide

• Ralf Theissmann,
• Manfred Kluwig and
• Thomas Koch

Beilstein J. Nanotechnol. 2014, 5, 1815–1822, doi:10.3762/bjnano.5.192

• , the size (distribution) of the final products is optimised for the optical pigment properties, which are described by using Mie's theory. Mie's theory states that the optimum particle size for refracting light is just about half the wavelength it is meant to interact with. Speaking of visible light, a

Controlling the optical and structural properties of ZnS–AgInS₂ nanocrystals by using a photo-induced process

• Takashi Yatsui,
• Fumihiro Morigaki and
• Tadashi Kawazoe

Beilstein J. Nanotechnol. 2014, 5, 1767–1773, doi:10.3762/bjnano.5.187

• during synthesis. Detailed analysis of transmission electron microscope images confirmed that the photo-induced synthesis yielded a high crystallinity of the ZAIS nanocrystals with small variations in size and content. Keywords: low toxicity; self-assembly; visible-light-emitting nanocrystals; ZnS

Non-covalent and reversible functionalization of carbon nanotubes

• Antonello Di Crescenzo,
• Valeria Ettorre and
• Antonella Fontana

Beilstein J. Nanotechnol. 2014, 5, 1675–1690, doi:10.3762/bjnano.5.178

• aggregation of nanotubes controlled by simple irradiating the sample under UV–visible light. Chen et al. pointed out that the UV photoirradiation of well-dispersed SWCNTs coated with a poly(ethylene glycol)-terminated malachite green derivative is responsible for the CNTs reaggregation [97]. Indeed, UV light

Near-field photochemical and radiation-induced chemical fabrication of nanopatterns of a self-assembled silane monolayer

• Ulrich C. Fischer,
• Carsten Hentschel,
• Florian Fontein,
• Linda Stegemann,
• Christiane Hoeppener,
• Harald Fuchs and
• Stefanie Hoeppener

Beilstein J. Nanotechnol. 2014, 5, 1441–1449, doi:10.3762/bjnano.5.156

• lithography (CL), which is either exposed to visible light, oxygen plasma or an UV–ozone atmosphere. The gold mask has the function to inhibit the photochemical reactions by highly localized near-field interactions between metal mask and SAM and to inhibit the radiation-induced chemical reactions by casting a

• functional groups, in which metal nanostructures, fabricated by CL, served as replaceable barrier nanostructures to guide localized self-assembly processes [23]. Earlier, submicroscopic pattern replication with visible light was introduced [20][24] as a near-field photochemical process to generate chemical

• photochemical reactions through UV radiation or visible light. In this way we intend to create additional means for a more flexible formation of chemically functional nanostructures with the potential for a high spatial resolution in the range of 10 nm. Three fabrication processes are demonstrated. In process 1

Enhanced photocatalytic hydrogen evolution by combining water soluble graphene with cobalt salts

• Jing Wang,
• Ke Feng,
• Hui-Hui Zhang,
• Bin Chen,
• Zhi-Jun Li,
• Qing-Yuan Meng,
• Li-Ping Zhang,
• Chen-Ho Tung and
• Li-Zhu Wu

Beilstein J. Nanotechnol. 2014, 5, 1167–1174, doi:10.3762/bjnano.5.128

• , Co(TEOA)22+ is formed in situ and adsorbed at the surface or around the G-SO3 when cobalt salts and G-SO3 are introduced into the hydrogen evolution system. Upon irradiation by visible light (525 nm LEDs as light source) for 4 h, the system is able to produce hydrogen with a TON up to 148 with the

Photocatalysis

• Rong Xu

Beilstein J. Nanotechnol. 2014, 5, 1071–1072, doi:10.3762/bjnano.5.119

• , two review articles present an excellent overview of the significance of nanostructures in visible light photocatalysis in a timely manner. Many materials aspects of photocatalysts influence the photocatalytic performance, such as the electronic, structural, and morphological features of the

• bismuth vanadium oxide cluster exemplifies these characteristics. Besides solar fuel production, photocatalysis has a long history in water treatment. In this Thematic Series, there is also a report on the latest development in the utilization of mesoporous cerium oxide for visible light-driven dye

DFT study of binding and electron transfer from colorless aromatic pollutants to a TiO₂ nanocluster: Application to photocatalytic degradation under visible light irradiation

• Corneliu I. Oprea,
• Petre Panait and
• Mihai A. Gîrţu

Beilstein J. Nanotechnol. 2014, 5, 1016–1030, doi:10.3762/bjnano.5.115

• order to explain experimental results regarding the photocatalytic degradation of these pollutants under visible light irradiation. Based on our modeling, we are able to clarify why transparent pollutants can degrade under visible light in the presence of a catalyst that absorbs only in the UV, to

• ; density functional theory; photocatalytic degradation; titanium dioxide; visible light irradiation; Introduction Titania, TiO2, has been widely used as photocatalyst for environmental applications [1][2][3][4][5][6], particularly for waste water purification. Due to its large band gap TiO2 absorbs only

• UV radiation, a fact that limits the efficiency and keeps the costs of the photocatalytic degradation of environmental pollutants high. To be used under visible light irradiation, in the range of wavelengths where the solar spectrum has its maximum, the electronic band structure of the photocatalyst

Functionalized nanostructures for enhanced photocatalytic performance under solar light

• Liejin Guo,
• Dengwei Jing,
• Maochang Liu,
• Yubin Chen,
• Shaohua Shen,
• Jinwen Shi and
• Kai Zhang

Beilstein J. Nanotechnol. 2014, 5, 994–1004, doi:10.3762/bjnano.5.113

• : visible-light activity, chemical stability, appropriate band-edge characteristics, and potential for low-cost fabrication. Our aim is to present a short review of our recent attempts that center on the above requirements. We begin with a brief introduction of photocatalysts coupling two or more

• band (CB) must be more negative than the reduction potential of water, while the top level of the valance band (VB) should be more positive than the oxidation potential of water. In order to utilize the abundant visible light from the sun, the band gap of photocatalysts has to be less than 3.0 eV

• should be pointed out that TiO2 can only respond to UV light, even metal ion doping can hardly enhance its visible light activity. Sensitization with dyes or nanocrystals is one possible approach to extend the light absorption of TiO2. Sreethawong et al. found that eosin Y-sensitized mesoporous-assembled

Growth and characterization of CNT–TiO₂ heterostructures

• Yucheng Zhang,
• Ivo Utke,
• Johann Michler,
• Gabriele Ilari,
• Marta D. Rossell and
• Rolf Erni

Beilstein J. Nanotechnol. 2014, 5, 946–955, doi:10.3762/bjnano.5.108

• -effectively and environmentally friendly, is a good candidate for electrochemical photocatalysis [6], recent research shows that its limited absorption of only the UV part of the sunlight spectrum can be extended to visible light when forming a nanocomposite with CNTs [7][8][9]. This can significantly

• discovery that with the addition of CNTs, the light absorption of TiO2 can be extended to the visible-light region [8][9][10][11][12][13][14]. This can significantly increase the photocatalytic efficiency. In literature several photocatalysis enhancement mechanisms based on TiO2–CNT have been proposed, as

Enhancement of photocatalytic H₂ evolution of eosin Y-sensitized reduced graphene oxide through a simple photoreaction

• Weiying Zhang,
• Yuexiang Li,
• Shaoqin Peng and
• Xiang Cai

Beilstein J. Nanotechnol. 2014, 5, 801–811, doi:10.3762/bjnano.5.92

• -RGO24/Pt for hydrogen evolution rises up to 12.9% under visible light irradiation (λ ≥ 420 nm), and 23.4% under monochromatic light irradiation at 520 nm. Fluorescence spectra and transient absorption decay spectra of the EY-sensitized RGO confirm that the electron transfer ability of RGO increases with

• under visible light irradiation. Eosin Y (EY), a xanthene dye, is a very good sensitizer [13][14][15][16][17][18]. EY has been used to sensitize various matrixes such as TiO2 [13], Na2Ti2O4(OH)2 nanotubes [14], g-C3N4 [15], and α-[AlSiW11(H2O)O39]5− [18], and the sensitized photocatalysts are

• characterized by a high activity for H2 evolution under visible light irradiation. Recently, to improve the photocatalytic activity for hydrogen evolution in the visible light region, EY has been employed to sensitize RGO, and the sensitized photocatalyst displays an increased photoactivity for hydrogen

Biomolecule-assisted synthesis of carbon nitride and sulfur-doped carbon nitride heterojunction nanosheets: An efficient heterojunction photocatalyst for photoelectrochemical applications

• Hua Bing Tao,
• Hong Bin Yang,
• Jiazang Chen,
• Jianwei Miao and
• Bin Liu

Beilstein J. Nanotechnol. 2014, 5, 770–777, doi:10.3762/bjnano.5.89

• : graphitic carbon nitride (g-C3N4); heterojunction; photoelectrochemical; photocatalysis; sulfur doping; Introduction Over the past few years, graphitic carbon nitride (CN) has attracted significant research attention in visible-light-driven photocatalysis because of its unique physical and chemical

• different light source and the EQE spectra. Figure 6c exhibits the photoresponse of CN, CNS and CN/CNS under different light sources. It can be observed that the photocurrent can be reproducibly produced under AM 1.5G simulated sunlight or visible light (λ > 420 nm) with the same trend following the order

• bias vs Ag/AgCl under simulated sunlight (AM 1.5, 100 mW/cm2) and visible light (λ > 420 nm). (d) External quantum efficiency (EQE) of CN, CNS and CN/CNS photoelectrodes. Supporting Information Supporting Information File 50: Additional experimental data. Acknowledgements The authors acknowledge

Visible light photooxidative performance of a high-nuclearity molecular bismuth vanadium oxide cluster

• Johannes Tucher and
• Carsten Streb

Beilstein J. Nanotechnol. 2014, 5, 711–716, doi:10.3762/bjnano.5.83

• Johannes Tucher Carsten Streb Ulm University, Institute of Inorganic Chemistry I, Albert-Einstein-Allee 11, 89081 Ulm, Germany 10.3762/bjnano.5.83 Abstract The visible light photooxidative performance of a new high-nuclearity molecular bismuth vanadium oxide cluster, H3[{Bi(dmso)3}4V13O40], is

• oxidant. Trapping experiments using ethanol as a hydroxyl radical scavenger show significantly decreased photocatalytic substrate oxidation in the presence of EtOH. Photocatalytic performance analyses using monochromatic visible light irradiation show that the quantum efficiency Φ for indigo

• , olefins and others [1][2][3][14]. However, as POMs often only absorb light in the UV range, little is known about the visible-light photocatalytic activity of POMs [5][15]. One means of addressing this challenge is to tune the cluster structure and reactivity by incorporation of a reactive metal site into

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• Hongjun Chen Lianzhou Wang Nanomaterials Centre, School of Chemical Engineering, The University of Queensland, St. Lucia, Brisbane, QLD, 4072, Australia 10.3762/bjnano.5.82 Abstract To better utilize the sunlight for efficient solar energy conversion, the research on visible-light active

• photocatalysts has recently attracted a lot of interest. The photosensitization of transition metal oxides is a promising approach for achieving effective visible-light photocatalysis. This review article primarily discusses the recent progress in the realm of a variety of nanostructured photosensitizers such as

• quantum dots, plasmonic metal nanostructures, and carbon nanostructures for coupling with wide-bandgap transition metal oxides to design better visible-light active photocatalysts. The underlying mechanisms of the composite photocatalysts, e.g., the light-induced charge separation and the subsequent

A visible-light-driven composite photocatalyst of TiO₂ nanotube arrays and graphene quantum dots

• Donald K. L. Chan,
• Po Ling Cheung and
• Jimmy C. Yu

Beilstein J. Nanotechnol. 2014, 5, 689–695, doi:10.3762/bjnano.5.81

• incorporation of graphene quantum dots could extend the photo-response of the nanotubes to the visible-light range. Graphene quantum dot-sensitized TiO2 nanotube arrays were synthesized by covalently coupling these two materials. The product was characterized by Fourier-transform infrared spectrometry (FTIR

• have been developed to achieve photoresponse of TiO2-based catalysts towards visible light, for example, doping with metal or non-metal [7][17][18][19][20], coupling with other semiconductor materials to form composite catalysts [4][21][22][23][24]. Two-dimensional graphene has attracted immense

• visible-light-driven photocatalysis [35][36]. Very recently, the combination of GQDs with CdS-modified TNAs was reported for photoelectrochemical hydrogen production. However, GQDs did not enhance the activity of bare TNAs in the study [37]. GQDs have also been chemically coupled with ZnO nanowires for

Effects of the preparation method on the structure and the visible-light photocatalytic activity of Ag₂CrO₄

• Difa Xu,
• Shaowen Cao,
• Jinfeng Zhang,
• Bei Cheng and
• Jiaguo Yu

Beilstein J. Nanotechnol. 2014, 5, 658–666, doi:10.3762/bjnano.5.77

• 10.3762/bjnano.5.77 Abstract Silver chromate (Ag2CrO4) photocatalysts are prepared by microemulsion, precipitation, and hydrothermal methods, in order to investigate the effect of preparation methods on the structure and the visible-light photocatalytic activity. It is found that the photocatalytic

• activity of the prepared Ag2CrO4was highly dependent on the preparation methods. The sample prepared by microemulsion method exhibits the highest photocatalytic efficiency on the degradation of methylene blue (MB) under visible-light irradiation. The enhanced photocatalytic activity could be ascribed to

• ; photocatalytic activity; silver chromate; visible-light-driven; Introduction Semiconductor photocatalysis has been considered as a potential solution to the worldwide energy shortage and for counteracting environmental degradation [1][2][3][4][5]. Numerous efforts have been made to develop efficient and stable

Enhanced photocatalytic activity of Ag–ZnO hybrid plasmonic nanostructures prepared by a facile wet chemical method

• Sini Kuriakose,
• Vandana Choudhary,
• Biswarup Satpati and
• Satyabrata Mohapatra

Beilstein J. Nanotechnol. 2014, 5, 639–650, doi:10.3762/bjnano.5.75

• visible region by controlling their size, shape, inter-particle spacing and surrounding medium [25]. In case of ZnO modified with noble metal nanoparticles, LSPR absorption can lead to enhanced utilization of UV–visible light as compared to pure ZnO [26][27][28]. Silver nanoparticles decorated ZnO

High activity of Ag-doped Cd_0.1Zn_0.9S photocatalyst prepared by the hydrothermal method for hydrogen production under visible-light irradiation

• Leny Yuliati,
• Melody Kimi and
• Mustaffa Shamsuddin

Beilstein J. Nanotechnol. 2014, 5, 587–595, doi:10.3762/bjnano.5.69

• activity of Cd0.1Zn0.9S was studied for the hydrogen production from water reduction under visible light irradiation. Results: Compared to the series prepared by the co-precipitation method, samples prepared by the hydrothermal method performed with a better photocatalytic activity. The sample with the

• optimum amount of Ag doping showed the highest hydrogen production rate of 3.91 mmol/h, which was 1.7 times higher than that of undoped Cd0.1Zn0.9S. With the Ag doping, a red shift in the optical response was observed, leading to a larger portion of the visible light absorption than that of without doping

• . In addition to the larger absorption in the visible-light region, the increase in photocatalytic activity of samples with Ag doping may also come from the Ag species facilitating electron–hole separation. Conclusion: This study demonstrated that Ag doping is a promising way to enhance the activity of

Artificial sunlight and ultraviolet light induced photo-epoxidation of propylene over V-Ti/MCM-41 photocatalyst

• Van-Huy Nguyen,
• Shawn D. Lin,
• Jeffrey Chi-Sheng Wu and
• Hsunling Bai

Beilstein J. Nanotechnol. 2014, 5, 566–576, doi:10.3762/bjnano.5.67

• received much attention. In this section, we examined the photo-epoxidation of propylene over V-Ti/MCM-41 by utilizing UV-visible light (without an AM1.5G filter) and artificial sunlight (with an AM1.5G filter). With UV–visible light, the C3H6 consumption rate and the PO formation rate with time on stream

• photocatalytic epoxidation of propylene. Both of UV–visible light and artificial sunlight show a similar and stable product distribution (Figure 5b and Figure 6b). The use of AM1.5G filter decreased the photo-activity but similar trends in PO formation rate and C3H6 consumption rate with time on stream are also

• lower cut-off wavelength of irradiation light (260 nm for UV, 200 nm for visible light and 310 nm for artificial light) to the cut-off absorbance of the catalyst (380 nm). The ratio of the integrated absorbance over the filtered range of the light source to the total absorption capacity is defined as

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

• photoelectron and UV–vis spectroscopy, and transmission electron microscopy. Together with N2 sorption experiments, the data confirms that the new cerium oxide material is mesoporous and absorbs visible light. The photocatalytic degradation of rhodamin B is investigated with a series of radical scavengers

• , suggesting that the mechanism of photocatalytic activity under visible-light irradiation involves predominantly hydroxyl radicals as the active species. Keywords: cerium oxide; dye degradation; mesoporous; photocatalysis; visible light; Introduction The degradation of organic pollutants by affordable and

• semiconductors have been explored for the visible-light driven photocatalytic degradation of pollutants and microbes, such as bismuth oxides [5][6] and cerium oxides [12][13]. CeO2 specifically has been applied in a number of sustainable energy applications lately, including oxidative catalysis, hydrogen storage

Encapsulation of nanoparticles into single-crystal ZnO nanorods and microrods

• Jinzhang Liu,
• Marco Notarianni,
• Llew Rintoul and
• Nunzio Motta

Beilstein J. Nanotechnol. 2014, 5, 485–493, doi:10.3762/bjnano.5.56

• to produce red luminescence. ZnO nanorod is transparent to visible light and emissions from NDs can transmit into ZnO nano/microrod to undergo multiple reflections. ZnO is a birefringent crystal with a refractive index of about 2.0 in the visible range, indicating the total refraction angle of light

Dye-sensitized Pt@TiO₂ core–shell nanostructures for the efficient photocatalytic generation of hydrogen

• Jun Fang,
• Lisha Yin,
• Shaowen Cao,
• Yusen Liao and
• Can Xue

Beilstein J. Nanotechnol. 2014, 5, 360–364, doi:10.3762/bjnano.5.41

• hydrothermal method. The dye-sensitization of these Pt@TiO2 core–shell structures allows for a high photocatalytic activity for the generation of hydrogen from proton reduction under visible-light irradiation. When the dyes and TiO2 were co-excited through the combination of two irradiation beams with

• ], TiO2 has received extensive attention as one of the promising semiconductor photocatalysts, because of its high chemical stability, low cost and non-toxicity [2][3][4][5]. However, it suffers from the wide band gap (3.2–3.4 eV), which restricts the utilization of visible light, and the high

• noble metal (e.g., Pt) nanoparticles as co-catalysts that can act as electron-sinks to achieve effective charge separation on TiO2 [7][8][9][10][11]. Dye-sensitization has been widely used to enable visible light harvesting by wide band gap semiconductors. Since the seminal work reported by O’Regan and

Noncontact atomic force microscopy II

• Mehmet Z. Baykara and
• Udo D. Schwarz

Beilstein J. Nanotechnol. 2014, 5, 289–290, doi:10.3762/bjnano.5.31

• needed. As such, breaking the resolution limit associated with the wavelength of visible light employed in traditional optical microscopy has been a long-standing dream of scientists around the world. This goal was finally reached in the early 1980s with the invention of the scanning tunneling microscope

Synthesis of embedded Au nanostructures by ion irradiation: influence of ion induced viscous flow and sputtering

• Udai B. Singh,
• D. C. Agarwal,
• S. A. Khan,
• S. Mohapatra,
• H. Amekura,
• D. P. Datta,
• Ajay Kumar,
• R. K. Choudhury,
• T. K. Chan,
• Thomas Osipowicz and
• D. K. Avasthi

Beilstein J. Nanotechnol. 2014, 5, 105–110, doi:10.3762/bjnano.5.10

• Au nanoparticles into the glass substrate. Keywords: embedded nanoparticles; ion beam irradiation; recoil implantation; Introduction Noble-metal nanoparticles (NPs) are of great interest due to their large surface-to-volume ratio and their enhanced absorption of visible light. The shape- and size

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

• photosensitized solar cells with high quantum yields [1][2][3][4] and the photocatalytic degradation of pollutants [5][6]. CdS, currently used as an efficient visible-light sensitizer, is a semiconductor that possesses a small band gap (2.4 eV) and suitable potential energies. The electron transfer between QDs