Circular dichroism of chiral Majorana states

• Javier Osca and
• Llorenç Serra

Beilstein J. Nanotechnol. 2018, 9, 1194–1199, doi:10.3762/bjnano.9.110

• hybrid structure made of a quantum-anomalous Hall insulator and a superconductor. The optical absorption of chiral Majorana states is characterized by equally spaced absorption peaks of both positive and negative dichroism. In the limit of a very long structure (a 2D ribbon) peaks of a single sign are

• favored. Conclusion: Circular-dichroism spectroscopy of chiral Majorana states is suggested as a relevant probe for these peculiar states of topological matter. Keywords: chiral states; circular dichroism; Majorana modes; optical absorption; topological matter; Introduction The physics of Majorana

• the connection between chiral Majorana states and optical absorption. We expect that in presence of chiral Majorana states, the optical absorption of circularly polarized light will differ for clockwise and anti-clockwise polarizations. The difference, known as circular dichroism (CD) [23][24], can

P3HT:PCBM blend films phase diagram on the base of variable-temperature spectroscopic ellipsometry

• Barbara Hajduk,
• Henryk Bednarski,
• Bożena Jarząbek,
• Henryk Janeczek and
• Paweł Nitschke

Beilstein J. Nanotechnol. 2018, 9, 1108–1115, doi:10.3762/bjnano.9.102

• their phase transitions using variable-temperature spectroscopic ellipsometry. We have investigated thin films of P3HT:PCBM blends deposited by spin-coating. Our studies included optical absorption spectroscopy, variable-temperature spectroscopic ellipsometry and differential scanning calorimetry. Based

Theoretical study of strain-dependent optical absorption in a doped self-assembled InAs/InGaAs/GaAs/AlGaAs quantum dot

• Tarek A. Ameen,
• Hesameddin Ilatikhameneh,
• Archana Tankasala,
• Yuling Hsueh,
• James Charles,
• Jim Fonseca,
• Michael Povolotskyi,
• Jun Oh Kim,
• Sanjay Krishna,
• Monica S. Allen,
• Jeffery W. Allen,
• Rajib Rahman and
• Gerhard Klimeck

Beilstein J. Nanotechnol. 2018, 9, 1075–1084, doi:10.3762/bjnano.9.99

• . 10.3762/bjnano.9.99 Abstract A detailed theoretical study of the optical absorption in doped self-assembled quantum dots is presented. A rigorous atomistic strain model as well as a sophisticated 20-band tight-binding model are used to ensure accurate prediction of the single particle states in these

• ]. However, we show that the original parameter set cannot reproduce the experimental optical absorption peaks in quantum dots [9]. Using these parameters to determine strain in quantum wells does not agree with the well-known analytical solution of strain in quantum wells. Optimizing the parameters to

• the wavefunctions of the electrons and holes are localized due to these disordered band edges, as the spatial overlap between the states determines the optical absorption spectrum. Hence, one can look at the conduction and valence band edges along arbitrary lines passing through the quantum dot. This

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

• recorded on a ASAP 2020 HD88 using the Brunauer–Emmett–Teller (BET) method at liquid nitrogen temperature 77 K. The optical absorption properties of the samples were measured by UV–vis spectra on a Hitachi U-4100 spectrophotometer equipped with an integrating sphere at room temperature in the region of 200

Mechanistic insights into plasmonic photocatalysts in utilizing visible light

• Kah Hon Leong,
• Azrina Abd Aziz,
• Lan Ching Sim,
• Pichiah Saravanan,
• Min Jang and
• Detlef Bahnemann

Beilstein J. Nanotechnol. 2018, 9, 628–648, doi:10.3762/bjnano.9.59

• of plasmonics are portrayed in Figure 1. Noble metals such as Au, Ag, Pt, Pd in the form of nanoparticles are a novel candidate for high absorption of visible light owing to their strong optical absorption in the entire solar region [8][9]. The unique characteristics of the LSPR effect in noble metal

• decay, H2O2 is the most stable of the molecules and can be detected separately. As of now, various methods have been employed for its quantification in photocatalysis reactions and could be classified as (1) direct optical absorption in UV and IR regions, (2) coloration and (3) fluorescence probe

• . Direct optical absorption The direct detection of H2O2 in solution by measuring UV spectra is difficult due to the weak molar absorption coefficient of H2O2 (0.01 M−1 cm−1) at 360 nm, which gradually increases up to 13 M−1 cm−1 at the wavelength of 260 nm [115]. Meanwhile, the optical absorption in the

Fabrication and photoactivity of ionic liquid–TiO₂ structures for efficient visible-light-induced photocatalytic decomposition of organic pollutants in aqueous phase

• Anna Gołąbiewska,
• Marta Paszkiewicz-Gawron,
• Aleksandra Sadzińska,
• Wojciech Lisowski,
• Ewelina Grabowska,
• Adriana Zaleska-Medynska and
• Justyna Łuczak

Beilstein J. Nanotechnol. 2018, 9, 580–590, doi:10.3762/bjnano.9.54

• absorption of the TiO2 photocatalysts appeared when the selected ionic liquids, [ODMIM][Cl] and [TDMIM][Cl], were applied in the TiO2 synthesis reaction. Moreover, with increasing IL:TBOT molar ratio, the optical absorption of the composites in the viible-light region was also greatly increased (compare for

• results the improvement of the optical absorption of the composites in the visible-light region could be associated with the synergic effect of its two main components, that is, TiO2 and ILs. Binetti et al. [42] stated that the absorbance of IL–TiO2 materials increased with the modification of TiO2 with 1

• absorption spectrum of the titanium dioxide in the visible region. Therefore, the enhanced photocatalytic activity of IL–TiO2 can be attributed to the improved optical absorption. Moreover, the XPS data showed that the amount of carbon, nitrogen and chlorine were higher for the samples with molar ratio 1:3

Colloidal solution of silver nanoparticles for label-free colorimetric sensing of ammonia in aqueous solutions

• Alessandro Buccolieri,
• Antonio Serra,
• Gabriele Giancane and
• Daniela Manno

Beilstein J. Nanotechnol. 2018, 9, 499–507, doi:10.3762/bjnano.9.48

• sensors [14]. The optical properties of gold and silver nanoparticles in the UV–vis region (200–800 nm) are well known. As an example, the peak of the optical absorption SPR is a feature of the colloidal metal nanoparticle solutions. The exact position of the absorption maximum and the shape of the peak

• all experiments, ammonia was added to colloidal solutions within 60 min after seed formation. The final colloidal solution is very stable:The optical absorption curves can be reproduced without any significant differences for at least five days. Spectroscopic and morphologic characterisations

Influence of the preparation method on the photocatalytic activity of Nd-modified TiO₂

• Patrycja Parnicka,
• Paweł Mazierski,
• Tomasz Grzyb,
• Wojciech Lisowski,
• Ewa Kowalska,
• Bunsho Ohtani,
• Adriana Zaleska-Medynska and
• Joanna Nadolna

Beilstein J. Nanotechnol. 2018, 9, 447–459, doi:10.3762/bjnano.9.43

• that for photocatalysts obtained by the SHT method the agglomerates are a bit smaller. Optical and photoluminescence properties To study the optical absorption properties of the as-prepared photocatalysts, diffuse reflectance spectra (DRS) in the range of 200–850 nm were investigated, and the results

• are shown in Figure 3. The optical absorption of TiO2 in the UV region below 400 nm can be mainly attributed to the charge transfer, related to electron excitation from the valence band to the conduction band (band-to-band transition, O2p→Ti3d) [30]. Modification of TiO2 with neodymium significantly

• affected the light absorption of the photocatalysts. A redshift of the absorption edge toward the visible region was observed for the Nd-modified samples. The optical absorption edge was shifted further when the SHT method was applied. Nassuko et al. reported that the redshift can be ascribed to the new

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

• analysis UV–vis diffuse reflectance spectra (DRS) were measured to determine the optical absorption properties of the ZFO samples. The samples show a wide absorption range from 200 to 700 nm as depicted in Figure 4a, and among them ZFO-500 shows the highest absorption. With increasing calcination

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

• separation. The interfacial electron transfer between two semiconductors has gained significant interest because the heterojunction improves both the optical absorption in the visible range and the charge separation yield and thus the charge carrier lifetime [3][4][5][6][7][8]. The photocatalytic activity is

• enhanced because oxidation of water by holes and reduction of oxygen by electrons are retained at two different sites. Recently, many groups demonstrated that the creation of a heterojunction between TiO2 and CdS, CdSe or alloyed CdSeS nanoparticles allows the optical absorption of TiO2 to be extended into

• high interest for use as sensitizers for photocatalytic applications due to their high surface area, higher optical absorption cross section (as compared to spherical particles) and easier charge carrier separation [38]. Only a couple of reports describe the association of CdSe NRs with TiO2. Luo et al

Changes of the absorption cross section of Si nanocrystals with temperature and distance

• Michael Greben,
• Petro Khoroshyy,
• Sebastian Gutsch,
• Daniel Hiller,
• Margit Zacharias and
• Jan Valenta

Beilstein J. Nanotechnol. 2017, 8, 2315–2323, doi:10.3762/bjnano.8.231

• the optical absorption coefficient [9]. The NC concentration is necessary for many scientific studies and practical applications such as biolabeling [3]. Besides this, the ACS is related to the transition oscillator strength and therefore, is a very useful parameter for a variety of theoretical

Synthesis and characterization of noble metal–titania core–shell nanostructures with tunable shell thickness

• Bartosz Bartosewicz,
• Marta Michalska-Domańska,
• Malwina Liszewska,
• Dariusz Zasada and
• Bartłomiej J. Jankiewicz

Beilstein J. Nanotechnol. 2017, 8, 2083–2093, doi:10.3762/bjnano.8.208

• great potential for use in these applications [18][19]. Surface plasmon resonance properties of gold and silver NPs can increase the optical absorption of titania and extend its absorption band to the visible light region. Such CSNs could allow one of the most important limitations in broader use of

Optical techniques for cervical neoplasia detection

• Tatiana Novikova

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

Charge transfer from and to manganese phthalocyanine: bulk materials and interfaces

• Florian Rückerl,
• Daniel Waas,
• Bernd Büchner,
• Martin Knupfer,
• Dietrich R. T. Zahn,
• Francisc Haidu,
• Torsten Hahn and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 1601–1615, doi:10.3762/bjnano.8.160

• reported [116]. Keeping this in mind, we present a comparison of our electronic excitation data obtained using EELS for MnPc, K1MnPc (MnPc−), and MnPc/F4TCNQ (MnPc+) in Figure 9. In addition, we also included the energies of optical absorption studies for oxidized and reduced MnPc in solution [117][118

• , K1MnPc and MnPc/F4TCNQ as measured using EELS. In the lower two panels, we compare these data to the optical absorption energies (denoted by vertical bars) as observed for (b) MnPc+ [117] and (c) MnPc− [118] in solution. In panel (b) we additionally show the optical absorption energy of F4TCNQ− radicals

Spin-chemistry concepts for spintronics scientists

• Konstantin L. Ivanov,
• Alexander Wagenpfahl,
• Carsten Deibel and
• Jörg Matysik

Beilstein J. Nanotechnol. 2017, 8, 1427–1445, doi:10.3762/bjnano.8.143

• the sum of the radical radii. MFEs can be studied using different techniques. The concentration of radicals, as well as the radical pair recombination yield can be traced by detecting optical absorption, luminescence, photocurrent, etc. These quantities can be monitored either in steady-state

• RYDMR technique, which can be used for two purposes: (i) controlling the reactivity of radical pairs by using spin degrees of freedom and (ii) obtaining EPR parameters of short-lived radicals and radical pairs. RYDMR spectra can be obtained [95] by monitoring optical absorption, luminescence of the

Synthesis, spectroscopic characterization and thermogravimetric analysis of two series of substituted (metallo)tetraphenylporphyrins

• Rasha K. Al-Shewiki,
• Carola Mende,
• Roy Buschbeck,
• Pablo F. Siles,
• Oliver G. Schmidt,
• Tobias Rüffer and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 1191–1204, doi:10.3762/bjnano.8.121

• concentration-dependent UV–vis measurements. According to [28] the nature (cofacial, face-to-face, tilted) and degree (dimer, oligomer, polymer) of mutual interactions between (metallo)phthalocyanine molecules might modify their optical absorption spectra [28]. However, the UV–vis studies of 2/2a–d and 3/3a–d

Surface-enhanced Raman spectroscopy of cell lysates mixed with silver nanoparticles for tumor classification

• Mohamed Hassoun,
• Iwan W.Schie,
• Tatiana Tolstik,
• Sarmiza E. Stanca,
• Christoph Krafft and
• Juergen Popp

Beilstein J. Nanotechnol. 2017, 8, 1183–1190, doi:10.3762/bjnano.8.120

• become electronically coupled, which results in a change of the surface plasmon resonance compared to individual particles. Figure 1b shows the effect of adding KCl to Ag nanoparticles on the optical absorption characteristics. The aggregated nanoparticles have a broad absorption band that allowed for

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

• the impregnation method. The optical absorption properties of the nanocomposites prepared by the impregnation method were investigated (see Supporting Information File 1, Figure S3). The TiO2 (NT) sample absorbs light in the UV region and exhibits a characteristic band for TiO2 at about 370 nm due to

Selective detection of Mg²⁺ ions via enhanced fluorescence emission using Au–DNA nanocomposites

• Tanushree Basu,
• Khyati Rana,
• Niranjan Das and
• Bonamali Pal

Beilstein J. Nanotechnol. 2017, 8, 762–771, doi:10.3762/bjnano.8.79

• from the observed changes in the optical absorption, plasmon band, zeta potential, DLS particle size distribution, as well as TEM and AFM surface morphology analysis. Circular dichroism studies also revealed that DNA-functionalized AuNP binding caused a conformational change in the DNA structure. Due

• of the metal ion interaction [16]. The Au–DNA NC was found to be fairly effective for the detection of Mg2+ ions as compared to Ca2+ and Fe2+ ions present in aqueous solution. The enhanced binding ability is likely due to the smaller size of the Mg2+ ions. Results and Discussion The optical

• absorption of different bare and DNA-modified AuNPs (AuNS-1, AuNS-2, AuNS-3 and AuNS-4) is shown in Supporting Information File 1, Figure S1. It was found that due to their size dependency [17], the plasmon band shift (summarized in Supporting Information File 1, Table S1) occurred towards longer wavelengths

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

• gap energy [5][6][7][8], Ta2O5 nanoparticles are an open area for researchers. Tantalum pentoxide is an n-type semiconductor. It absorbs only UV light due to its wide band gap. Nevertheless, band gap modification through various methods has been proven to be successful for the red-shift of the optical

• absorption of these materials [9][10][11]. Tantalum(V) alkoxides are important precursors for materials based on tantalum oxide in sol–gel processes. The reactions involved in sol–gel processes can be written as: An inorganic network is formed during hydrolysis the ends of which are occupied either by –OH

Study of the surface properties of ZnO nanocolumns used for thin-film solar cells

• Neda Neykova,
• Jiri Stuchlik,
• Karel Hruska,
• Ales Poruba,
• Zdenek Remes and
• Ognen Pop-Georgievski

Beilstein J. Nanotechnol. 2017, 8, 446–451, doi:10.3762/bjnano.8.48

• were prepared before by DC reactive magnetron sputtering. The optical absorption of the pristine ZnO layers as well as that of the substrates bearing the dense ZnO NCs was investigated by photothermal deflection spectroscopy (PDS) [16][17]. Furthermore, we investigated the changes in the PDS spectrum

• -plasma for 1, 5, 10 and 25 min. The measured PDS absorptance spectra reflect the absorption edge, Urbach tail, absorption on defects and free-carrier absorption (proportional to the concentration of free carriers). All optical absorptance spectra show the optical absorption edge at a photon energy of 3.3

• eV and the free-carrier absorption in the red and the infrared part of the spectrum below photon energies of 2 eV. The infrared optical absorption increases with hydrogen plasma treatment indicating the increase of the free-carrier concentration as described in the Drude model. The increase of the

Laser irradiation in water for the novel, scalable synthesis of black TiO_x photocatalyst for environmental remediation

• Massimo Zimbone,
• Giuseppe Cacciato,
• Mohamed Boutinguiza,
• Vittorio Privitera and
• Maria Grazia Grimaldi

Beilstein J. Nanotechnol. 2017, 8, 196–202, doi:10.3762/bjnano.8.21

• its low band gap and large optical absorption [20][21] in the visible and IR spectral range. This material has also encouraged theoretical studies due to its peculiarities related to the hydrogen insertion. In the case of TiO2 nanoparticles, hydrogen induces the amorphization of a layer at the surface

Optical and photocatalytic properties of TiO₂ nanoplumes

• Viviana Scuderi,
• Massimo Zimbone,
• Maria Miritello,
• Giuseppe Nicotra,
• Giuliana Impellizzeri and
• Vittorio Privitera

Beilstein J. Nanotechnol. 2017, 8, 190–195, doi:10.3762/bjnano.8.20

• synthesize black TiO2 with a large optical absorption in the visible and infrared region [15][16][17][18]. The amorphous shell on a crystalline nanoparticle core, causes the formation of intragap states [19], which are responsible for the high absorption of visible light (and consequently of the black color

Tandem polymer solar cells: simulation and optimization through a multiscale scheme

• Fanan Wei,
• Ligang Yao,
• Fei Lan,
• Guangyong Li and
• Lianqing Liu

Beilstein J. Nanotechnol. 2017, 8, 123–133, doi:10.3762/bjnano.8.13

• the incident light achieves relatively better performance than the configuration with PCPDTBT/PCBM at the front. As a lower band gap, active material, PCPDTBT has considerably stronger optical absorption than P3HT. Thus, if the sub-cell with PCPDTBT is put first, a large portion of light energy will

Streptavidin-coated gold nanoparticles: critical role of oligonucleotides on stability and fractal aggregation

• Roberta D'Agata,
• Pasquale Palladino and
• Giuseppe Spoto

Beilstein J. Nanotechnol. 2017, 8, 1–11, doi:10.3762/bjnano.8.1

• was achieved by adding 10 µL of 100 μM BiotinDNA to the AuNPs water solutions. Characterization of nanoparticles Optical absorption measurements were performed with NanodropTM 1000 and Agilent 8453 spectrophotometers. Spectra were collected in the 200–800 nm range. Nanoparticles were analysed by using