Geometrical optimisation of core–shell nanowire arrays for enhanced absorption in thin crystalline silicon heterojunction solar cells

• Robin Vismara,
• Olindo Isabella,
• Andrea Ingenito,
• Fai Tong Si and
• Miro Zeman

Beilstein J. Nanotechnol. 2019, 10, 322–331, doi:10.3762/bjnano.10.31

• reflectance measured by means of a Perkin Elmer LAMBDA 950 UV–vis–NIR spectrophotometer. Modelling approach Simulations of the radial heterojunction c-Si nanowire solar cell were carried out by means of a 3D Maxwell equation solver, based on the finite element method (FEM). The “High Frequency Structure

• Information File 1, the implied photocurrent density losses, due to reflection and parasitic absorption in supporting layers, are included. It can be observed that an increase in NW height reduces reflectance. This can be expected since (in general) taller nanostructures exhibit better anti-reflection

• other hand, reflectance losses are significant for narrow nanowires (d < 200 nm), decreasing sharply until reaching a minimum between 400 and 500 nm. For larger values of the cross section (d > 500 nm), reflection losses become larger again. This behaviour can be explained as follows: When d is too

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

• thickness of 100 nm derived from SEM images (Table 3). The absorption coefficient α was determined as where d is the layer thickness, R is the total reflectance, included to compensate for thin film interference, and T is the total transmittance. The band gap of Sb2S3 layers was determined by plotting (αhν

• accounting for reflectance in α calculations. Thus, the absolute values of α may deviate from the expected values with the uncertainty introduced by using a constant layer thickness in calculations. The α vs wavelength plots of samples, which contain as-deposited or vacuum-treated Sb2S3 layers deposited from

• 0.02°, 5°/min, silicon strip detector D/teX Ultra). The crystal structure and phase composition were analyzed using Rigaku PDXL 2 software. Optical total transmittance and total reflectance spectra of glass/ITO/TiO2 reference and glass/ITO/TiO2/Sb2S3 samples were measured in the 250–1600 nm range vs

Amorphous Ni_xCo_yP-supported TiO₂ nanotube arrays as an efficient hydrogen evolution reaction electrocatalyst in acidic solution

• Yong Li,
• Peng Yang,
• Bin Wang and
• Zhongqing Liu

Beilstein J. Nanotechnol. 2019, 10, 62–70, doi:10.3762/bjnano.10.6

• crystallographic texture, scanning electron microscopy (SEM, JSM-5900 LV, JEOV) for micro-morphology, transmission electron microscopy (TEM, Tecnai G2 F20 S-TWIN) for microstructure, UV–vis diffuse reflectance spectroscopy (UV2100) for photoabsorption properties, X-ray photoelectron spectroscopy (XPS, Escalab

Zn/F-doped tin oxide nanoparticles synthesized by laser pyrolysis: structural and optical properties

• Florian Dumitrache,
• Iuliana P. Morjan,
• Elena Dutu,
• Ion Morjan,
• Claudiu Teodor Fleaca,
• Monica Scarisoreanu,
• Alina Ilie,
• Marius Dumitru,
• Cristian Mihailescu,
• Adriana Smarandache and
• Gabriel Prodan

Beilstein J. Nanotechnol. 2019, 10, 9–21, doi:10.3762/bjnano.10.2

• valuable from a technological point of view are its electrical conductivity, which is strongly affected by the surface states and the presence of dopants, transparency in the visible light range, high reflectance in the infrared range, and its classification as not potentially toxic or harmful [2][3]. The

• samples, yet in our case, the UV–vis absorption in this region seems to be considerably lower. Unfortunately, in the methods employed to extract the absorbance (diffuse reflectance spectroscopy using BaSO4 reflectance standard in [53] vs direct absorption from ethanolic suspensions in our study), the

Colloidal chemistry with patchy silica nanoparticles

• Pierre-Etienne Rouet,
• Cyril Chomette,
• Laurent Adumeau,
• Etienne Duguet and
• Serge Ravaine

Beilstein J. Nanotechnol. 2018, 9, 2989–2998, doi:10.3762/bjnano.9.278

• carboxylic acid groups. The grafting efficiency was evidenced by zeta potential measurements and diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy. Figure 2b shows that after treatment of the silica surface by APTES, the so-aminated nanoparticles display a quite high zeta potential value of

• -resolution SEM experiments with a JSM 6700F microscope at the Plateforme de Caractérisation des Matériaux d’Aquitaine (PLACAMAT). One drop of the CMs suspension was deposited on a glass slide. It was then dried in the open air, metalized, and placed in a box away from dust. Diffuse reflectance infrared

Optimization of Mo/Cr bilayer back contacts for thin-film solar cells

• Nima Khoshsirat,
• Fawad Ali,
• Vincent Tiing Tiong,
• Mojtaba Amjadipour,
• Hongxia Wang,
• Mahnaz Shafiei and
• Nunzio Motta

Beilstein J. Nanotechnol. 2018, 9, 2700–2707, doi:10.3762/bjnano.9.252

• different deposition powers and working pressures. Good adhesion to the SLG substrate has been achieved by means of an ultra-thin Cr layer under the Mo layer. By optimizing the deposition conditions we achieved low surface roughness, high optical reflectance and low sheet resistivity while we could decrease

• ; bilayer; chromium; DC sputtering; molybdenum; optical reflectance; Introduction Molybdenum (Mo) thin films are widely used as a back contact for photovoltaic devices such as Cu(In1−xGax)S2 (CIGS) and Cu2ZnSnS4 (CZTS) thin-film solar cells. The back contact is the first layer to be deposited and its

• a functions of the sputtering power and pressure [8][9]. The most successful approach suggested so far to improve the adhesion of Mo back contact layer to the glass substrate (while retaining its conductivity and optical reflectance) is through the deposition of a Mo bilayer rather than a single

Au–Si plasmonic platforms: synthesis, structure and FDTD simulations

• Anna Gapska,
• Marcin Łapiński,
• Paweł Syty,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2018, 9, 2599–2608, doi:10.3762/bjnano.9.241

• ). XPS spectra were analyzed with the Casa-XPS software using a Shirley background subtraction and Gaussian–Lorentzian curves for fitting. UV–vis spectra were recorded by a double-beam Thermo Fisher Scientific Evolution 220 spectrophotometer in reflectance mode. The spectra were recorded in a range of

Non-agglomerated silicon–organic nanoparticles and their nanocomplexes with oligonucleotides: synthesis and properties

• Asya S. Levina,
• Marina N. Repkova,
• Nadezhda V. Shikina,
• Zinfer R. Ismagilov,
• Svetlana A. Yashnik,
• Dmitrii V. Semenov,
• Yulia I. Savinovskaya,
• Natalia A. Mazurkova,
• Inna A. Pyshnaya and
• Valentina F. Zarytova

Beilstein J. Nanotechnol. 2018, 9, 2516–2525, doi:10.3762/bjnano.9.234

• Si–NH2 solution was recorded on a Cary 660 FTIR spectrometer (Agilent Technologies, USA) within the range of 4000–500 cm−1 at 4 cm−1 resolution, and 100 scans were accumulated in the attenuated total reflectance (ATR) mode using a GladiATR unit (Pike Technologies). The spectrum of the substance is

Thickness-dependent photoelectrochemical properties of a semitransparent Co₃O₄ photocathode

• Malkeshkumar Patel and
• Joondong Kim

Beilstein J. Nanotechnol. 2018, 9, 2432–2442, doi:10.3762/bjnano.9.228

• layer and the reflectance, respectively. Figure 2b shows α estimated as a function of photon energy (hν). The influence of the Co3O4 morphology on α is interesting. Except for the 70 nm film, α increases with thickness, suggesting an increase in porosity as well. A higher porosity led to higher α values

Performance analysis of rigorous coupled-wave analysis and its integration in a coupled modeling approach for optical simulation of complete heterojunction silicon solar cells

• Ziga Lokar,
• Benjamin Lipovsek,
• Marko Topic and
• Janez Krc

Beilstein J. Nanotechnol. 2018, 9, 2315–2329, doi:10.3762/bjnano.9.216

• (feature sizes of a few micrometers), this is not the case. Small textures were optimized to decrease the reflectance, and consequently, increase the absorption in the active layers of the solar cell. Decreasing the flat parts of the texture was shown to improve performance. For simulations of structures

• efficient simulation and optimization of solar cell structures. On the other hand, smaller number of sublayers and modes may lead to inaccuracies of results. In next subsections we present simulation results on total reflectance, R, in the EVA medium of the analyzed partial structure. Besides comparison of

• calculated an absolute difference (error) in JSC reflectance loss, |ΔJSC|, from deviations in R, as given in Equation 1 as where q is the elementary charge, is the reduced Planck constant and c is the speed of light. This parameter is defined as the absolute value of the reflectance difference, which is

Two-dimensional photonic crystals increasing vertical light emission from Si nanocrystal-rich thin layers

• Lukáš Ondič,
• Marian Varga,
• Ivan Pelant,
• Alexander Kromka,
• Karel Hruška and
• Robert G. Elliman

Beilstein J. Nanotechnol. 2018, 9, 2287–2296, doi:10.3762/bjnano.9.213

• reflectance spectra. The extraction enhancement within different spatial angles was evaluated by means of micro-photoluminescence spectroscopy. More than 18-fold extraction enhancement was achieved for light propagating in the normal direction and up to 22% increase in overall intensity was obtained at the

• spectral resolution was therefore used only for the simulation of the normal-incidence spectra, which reveals leaky modes at the Γ−point. For the case of angle-resolved reflectance simulations, which will also be presented in this paper, the spectral resolution was decreased to 10−4 nm. By this, even

• though the intensity values of the calculated resonances are not correct, their spectral position could be used for obtaining a qualitative information about the dispersion of photonic bands. As it will be shown later, the angle-resolved reflectance spectra calculated using the lower resolution are in

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

Sulfur-, nitrogen- and platinum-doped titania thin films with high catalytic efficiency under visible-light illumination

• Boštjan Žener,
• Lev Matoh,
• Giorgio Carraro,
• Bojan Miljević and
• Romana Cerc Korošec

Beilstein J. Nanotechnol. 2018, 9, 1629–1640, doi:10.3762/bjnano.9.155

• distribution (≈10 nm), whereas S3 has a multimodal pore size distribution. The distributions of pores in other samples synthesized with HCl (Urea_15, Thiourea_15) and H2SO4 (S3_N0.5, S3_N0.5+1% Pt) are similar to the distributions shown in Figure 3. Band gap measurements The diffuse reflectance, R, of the

• measured samples as a function of the wavelength λ is shown in the Figure 4a, and in Figure 4b, one can see the modified Kubelka–Munk function, (F(R)hν)n, vs energy, Eg, where F is the Kubelka–Munk function of the measured diffuse reflectance R as follows: F(R) = (1 − R)2 / 2R. The band gap energy was

• emission scanning electron microscope (FEI Inspect™ F50 and Ultra Plus Zeiss). The band gap measurements were performed by measuring the reflectance of the samples using a UV–vis spectrophotometer (Evolution 600, Thermo Scientific), using the diffuse reflectance accessory (DRA-EV-600) integrating sphere

Nanocomposites comprised of homogeneously dispersed magnetic iron-oxide nanoparticles and poly(methyl methacrylate)

• Sašo Gyergyek,
• David Pahovnik,
• Ema Žagar,
• Alenka Mertelj,
• Rok Kostanjšek,
• Miloš Beković,
• Marko Jagodič,
• Heinrich Hofmann and
• Darko Makovec

Beilstein J. Nanotechnol. 2018, 9, 1613–1622, doi:10.3762/bjnano.9.153

• -shift standard. The diffuse reflectance infrared Fourier transform spectra (DRIFT, Perkin Elmer Spectrum 400 equipped with DRIFT accessory) were recorded in KBr. The weight fraction of nanoparticles in the nanocomposites was determined with a Mettler Toledo thermogravimetric analysis (TGA) instrument

Sheet-on-belt branched TiO₂(B)/rGO powders with enhanced photocatalytic activity

• Huan Xing,
• Wei Wen and
• Jin-Ming Wu

Beilstein J. Nanotechnol. 2018, 9, 1550–1557, doi:10.3762/bjnano.9.146

• 10 mW. The X-ray photoelectron spectra (XPS) characterization was tested on an ESCA spectrometer (S-Probe ESCA SSX-100S, Fisons Instrument) and monochromatized Al Kα X-ray irradiation. The binding energy was calibrated by using the containment carbon (C 1s = 284.6 eV). The UV–vis diffuse reflectance

• , and (d) O 1s for sample TGN-branch 4 h. (a) UV–vis diffuse reflectance spectra of TGN and TGN-branch 4 h. (b) Re-plotting of (a) in the α1/2 ~ hν coordinate to evaluate the corresponding band gap, assuming an indirect transition between bands for TiO2. Photodegradation of phenol in the presence of

Cathodoluminescence as a probe of the optical properties of resonant apertures in a metallic film

• Kalpana Singh,
• Evgeniy Panchenko,
• Babak Nasr,
• Amelia Liu,
• Lukas Wesemann,
• Timothy J. Davis and
• Ann Roberts

Beilstein J. Nanotechnol. 2018, 9, 1491–1500, doi:10.3762/bjnano.9.140

• optical investigations of isolated holes are, however, challenging since the throughput and reflectance are low despite the enhanced localized fields. Furthermore, plasmonic cavities exhibit a wide range of modes, many of which are “dark” to normally incident plane waves and challenging to excite using

Cr(VI) remediation from aqueous environment through modified-TiO₂-mediated photocatalytic reduction

• Rashmi Acharya,
• Brundabana Naik and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 1448–1470, doi:10.3762/bjnano.9.137

• studies. Optical studies such as ultraviolet–visible diffuse reflectance spectroscopy (UV–vis DRS) and photoluminescence spectroscopy (PL) explain the shift of the absorption range to the visible region and prohibition of recombination of charge carriers, respectively. The doping of nonmetals such as N, S

Tailoring polarization and magnetization of absorbing terahertz metamaterials using a cut-wire sandwich structure

• Hadi Teguh Yudistira,
• Shuo Liu,
• Tie Jun Cui and
• Han Zhang

Beilstein J. Nanotechnol. 2018, 9, 1437–1447, doi:10.3762/bjnano.9.136

• Discussion The absorbance (A(ω)) of the material was calculated from the reflectance (R(ω)) and transmittance (T(ω)) by using the following equation: A(ω) = 1 − R(ω) − T(ω). Smith et al. [36] defined transmittance and reflectance as and Where t(ω), r(ω), n, k0, d and z are the transmissivity, reflectivity

• , refractive index, wave number in free space, substrate thickness and impedance, respectively. In the matching air impedance condition (i.e., z = 1 + i0), the reflectance would be zero and Equation 1 is expressed as where nr and ni are the real and imaginary parts of the refractive index, respectively

• × 1015 s−1. ω, ωp,Au and ΓAu are the angular frequency, angular plasma frequency of gold, and damping constant of gold, respectively. Figure 3 presents the reflectance–transmittance–absorbance (RTA) simulation result of cut-wire (Figure 3a), cross-shaped (Figure 3b) and star-shaped sandwich structures

Colorimetric detection of Cu²⁺ based on the formation of peptide–copper complexes on silver nanoparticle surfaces

• Gajanan Sampatrao Ghodake,
• Surendra Krishna Shinde,
• Rijuta Ganesh Saratale,
• Avinash Ashok Kadam,
• Ganesh Dattatraya Saratale,
• Asad Syed,
• Fuad Ameen and
• Dae-Young Kim

Beilstein J. Nanotechnol. 2018, 9, 1414–1422, doi:10.3762/bjnano.9.134

• Scientific Nicolet iS5 FTIR spectrometer equipped with a attenuated total reflectance tool, in the 1000–4000 cm−1 wavelength range at 0.48 cm−1 resolution. Selectivity To assess the selectivity of the proposed method, coordination of the functionalized AgNPs was tested with various ions, including Cu2+, Mn2

Ag₂WO₄ nanorods decorated with AgI nanoparticles: Novel and efficient visible-light-driven photocatalysts for the degradation of water pollutants

• Shijie Li,
• Shiwei Hu,
• Wei Jiang,
• Yanping Liu,
• Yu Liu,
• Yingtang Zhou,
• Liuye Mo and
• Jianshe Liu

Beilstein J. Nanotechnol. 2018, 9, 1308–1316, doi:10.3762/bjnano.9.123

• the formation of the AgI/Ag2WO4 heterojunctions, thereby facilitating the charge transfer between them [12]. Subsequently, the optical properties of as-prepared photocatalysts were investigated by UV–vis diffuse reflectance spectroscopy (DRS) analysis (Figure 4). As indicated from Figure 4, pure

• scanning electron microscope (FE-SEM, Hitachi S–4800) and a high-resolution transmission electron microscope (HRTEM, JEOL JEM–2010F). Energy-dispersive X-ray (EDX) spectroscopy coupled with SEM was employed to identify the chemical composition of the sample. UV–vis diffuse reflectance spectra (UV–vis DRS

• 0.4AgI/Ag2WO4. SEM (a, b) images of Ag2WO4; SEM (c, d), TEM (e), and HRTEM (f) images of 0.3AgI/Ag2WO4. Energy-dispersive X-ray (EDX) spectrum of 0.3AgI/Ag2WO4. UV–vis diffuse reflectance spectra of Ag2WO4, AgI, 0.1AgI/Ag2WO4, 0.2AgI/Ag2WO4, 0.3AgI/Ag2WO4, and 0.4AgI/Ag2WO4. (a) The photocatalytic

Semi-automatic spray pyrolysis deposition of thin, transparent, titania films as blocking layers for dye-sensitized and perovskite solar cells

• Hana Krýsová,
• Josef Krýsa and
• Ladislav Kavan

Beilstein J. Nanotechnol. 2018, 9, 1135–1145, doi:10.3762/bjnano.9.105

• microscopy (SEM) (Hitachi FE SEM S-4800 microscope), and UV–vis spectroscopy (Varian CARY 100 with integrating sphere DRA-CA-30I and 8° reflectance geometry, Varian, USA). X-ray fluorescence spectroscopy (XRF) analysis was performed on an ARL 9400 XP sequential WD-XRF spectrometer (Thermo ARL, Switzerland

Enzymatically promoted release of organic molecules linked to magnetic nanoparticles

• Chiara Lambruschini,
• Silvia Villa,
• Luca Banfi,
• Fabio Canepa,
• Fabio Morana,
• Annalisa Relini,
• Paola Riani,
• Renata Riva and
• Fulvio Silvetti

Beilstein J. Nanotechnol. 2018, 9, 986–999, doi:10.3762/bjnano.9.92

• reflectance (ATR) sampling accessory. The morphology of the particles was analysed using a field emission scanning electron microscope (FE-SEM, ZEISS SUPRA 40VP), collecting the signal (secondary electrons) by means of an in-lens detector; the particle microanalyses were performed with an energy dispersive X

Facile chemical routes to mesoporous silver substrates for SERS analysis

• Elina A. Tastekova,
• Alexander Y. Polyakov,
• Anastasia E. Goldt,
• Alexander V. Sidorov,
• Alexandra A. Oshmyanskaya,
• Irina V. Sukhorukova,
• Dmitry V. Shtansky,
• Wolgang Grünert and
• Anastasia V. Grigorieva

Beilstein J. Nanotechnol. 2018, 9, 880–889, doi:10.3762/bjnano.9.82

• Perkin Elmer Lambda 950 UV/Vis/NIR spectrophotometer in total reflectance regime. The samples were placed onto the reflectance port of a Spectralon-coated integrating sphere (d = 150 mm). The specular and diffusive reflectance signals were detected in the 300–1200 nm range (1 nm step) and replotted in

• of mesoporous silver films after immersion for 40 min in NaBH4 (a) without PVP and (b) with 5 mM of PVP, respectively. In (c) and (d) the micrographs of initial magnetron silver film and Ag2O films are presented. Optical absorbance spectra replotted from total reflectance data collected by an

Noble metal-modified titania with visible-light activity for the decomposition of microorganisms

• Maya Endo,
• Zhishun Wei,
• Kunlei Wang,
• Baris Karabiyik,
• Kenta Yoshiiri,
• Paulina Rokicka,
• Bunsho Ohtani,
• Agata Markowska-Szczupak and
• Ewa Kowalska

Beilstein J. Nanotechnol. 2018, 9, 829–841, doi:10.3762/bjnano.9.77

• were modified with silver and gold by photodeposition, and characterized by diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM). It was found that silver co-existed in zero valent (core) and

• silver-modified samples were brown-violet. Exemplary diffuse reflectance spectra (DRS) are shown in Figure 4. It should be pointed out that LSPR of silver could overlap with photoabsorption of titania, and thus to obtain clear LSPR peak of silver, DRS taken with bare titania as reference is recommended

Perovskite-structured CaTiO₃ coupled with g-C₃N₄ as a heterojunction photocatalyst for organic pollutant degradation

• Ashish Kumar,
• Christian Schuerings,
• Suneel Kumar,
• Ajay Kumar and
• Venkata Krishnan

Beilstein J. Nanotechnol. 2018, 9, 671–685, doi:10.3762/bjnano.9.62

• disk was measured by diffuse reflectance spectroscopy (DRS). DRS studies were performed on a Perkin Elmer UV–visible–NIR Lambda 750 spectrophotometer by utilizing polytetrafluoroethylene (PTFE) polymer as a diffuse reflectance standard in the wavelength range 200–800 nm. Photoluminescence (PL

• ) CTCN heterojunctions. TEM images of (a, b) g-C3N4 nanosheets, (c, d) CT flakes and (e, f) CTCN heterojunction. (a) UV–visible diffuse reflectance spectroscopy (DRS) spectra for g-C3N4, CT and CTCN heterojunction; Plot of transformed Kubelka–Munk function vs energy for (b) g-C3N4, (c) CT and (d) CTCN