Recent advances in green carbon dots (2015–2022): synthesis, metal ion sensing, and biological applications

• Aisha Kanwal,
• Naheed Bibi,
• Sajjad Hyder,
• Arif Muhammad,
• Hao Ren,
• Jiangtao Liu and
• Zhongli Lei

Beilstein J. Nanotechnol. 2022, 13, 1068–1107, doi:10.3762/bjnano.13.93

Optimizing PMMA solutions to suppress contamination in the transfer of CVD graphene for batch production

• Chun-Da Liao,
• Andrea Capasso,
• Tiago Queirós,
• Telma Domingues,
• Fatima Cerqueira,
• Nicoleta Nicoara,
• Jérôme Borme,
• Paulo Freitas and
• Pedro Alpuim

Beilstein J. Nanotechnol. 2022, 13, 796–806, doi:10.3762/bjnano.13.70

• average molecular weight (AMW) and weight concentration in anisole, to be deposited by spin coating. Optical microscopy and Raman spectroscopy showed that the amount of PMMA residues on transferred graphene is proportional to the AMW and concentration in the solvent. At the same time, the mechanical

• that the PMMA mixture features good mechanical strength and cleanness (i.e., the acetone bath can thoroughly remove it). The transferred graphene samples were investigated via Raman spectroscopy to evaluate crystallinity, layer number, and structural defect level [23]. The relative intensities of the G

• (ca. 1585 cm−1) and 2D (ca. 2700 cm−1) bands are typical of monolayer graphene [23][24][25][26]. The defect density appears minimal considering the negligible D band intensity at ca. 1350 cm−1 (Figure 2c) [27]. The Raman mapping in Figure 2d–i examines the whole crystal area [28]. The map and the

Efficient liquid exfoliation of KP₁₅ nanowires aided by Hansen's empirical theory

• Zhaoxuan Huang,
• Zhikang Jiang,
• Nan Tian,
• Disheng Yao,
• Fei Long,
• Yanhan Yang and
• Danmin Liu

Beilstein J. Nanotechnol. 2022, 13, 788–795, doi:10.3762/bjnano.13.69

• value below 100 nm. The thinnest KP15 nanowires reached 5.1 nm and had smooth boundaries. Meanwhile, strong temperature-dependent Raman response in exfoliated KP15 nanowires has been observed, which indicates a strong phonon–phonon coupling in those nanowires. This is helpful for non-invasive

• temperature measurements of KP15 nanodevices. Keywords: Hansen's empirical theory; KP15; liquid exfoliation; nanodevices; nanowires; Raman; semiconductors; Introduction Low-dimensional materials have drawn significant attention in recent years. So far, not only new composite materials with excellent

• reached 5.1 nm and had smooth boundaries. Meanwhile, a strong temperature-dependent Raman response was found in exfoliated KP15 nanowires. This indicates a strong phonon–phonon coupling in KP15 nanowires, which favors non-invasive temperature measurements of KP15 nanodevices. Methods Synthesis of KP15

A nonenzymatic reduced graphene oxide-based nanosensor for parathion

• Sarani Sen,
• Anurag Roy,
• Ambarish Sanyal and
• Parukuttyamma Sujatha Devi

Beilstein J. Nanotechnol. 2022, 13, 730–744, doi:10.3762/bjnano.13.65

• modified electrodes was carried out in 5 mM of [Fe(CN)6]3− and [Fe(CN)6]4− with 0.1 M KCl within the frequency range from 1 MHz to 0.01 Hz, amplitude of 10 mV, at a fixed potential of 0.28 V. The UV–visible absorbance spectra were obtained on a UV–vis–NIR spectrophotometer (SHIMADZU UV-3600). The Raman

• spectra of the samples were recorded in the 1000–3500 cm−1 region with a resolution of 1 cm−1 using a Renishaw via a Reflex micro-Raman spectrometer with an argon ion (514.6 nm) laser. The X-ray photoemission spectroscopy (XPS) data were obtained from a PHI 5000 Versa probe II scanning XPS microprobe

• develop better functioning electrodes. Raman spectroscopy has been frequently used as a reliable technique to optimize the electrochemical parameters for the synthesis of ERGO in terms of the intensity ratio of D- (disordered band) to G-band (graphitic band) (ID/IG). It measures the change in size of the

Nanoarchitectonics of the cathode to improve the reversibility of Li–O₂ batteries

• Hien Thi Thu Pham,
• Jonghyeok Yun,
• So Yeun Kim,
• Sang A Han,
• Jung Ho Kim,
• Jong-Won Lee and
• Min-Sik Park

Beilstein J. Nanotechnol. 2022, 13, 689–698, doi:10.3762/bjnano.13.61

• composites. Figure 2b compares Raman spectra of ZnxCoy–C/CNT composites, showing typical Raman bands at ≈1346 cm−1 (D band), ≈1576 cm−1 (G band), and ≈2680 cm−1 (2D band). All the composites show similar Raman scattering without a noticeable difference in full width at half maximum (FWHM) values. Assuming

• microstructures of the materials. Powder XRD (PANalytical, Empyrean) and Raman spectroscopy (inVia Raman microscopes, Ar ion laser, 514 nm) were employed to analyze the structures. Their surface chemistry was investigated by XPS (Thermo Scientific, Sigma Probe), while their surface area and porosity were

• ZnxCoy–CNT. FESEM images of (b, c, d) as-prepared and (e, f, g) etched composites. (b, e) Zn4Co1–CNT, (c, f) Zn1Co1–CNT, and (d, g) Zn1Co4–CNT. (a) XRD patterns and (b) Raman spectra of ZnxCoy–C/CNT composites. TEM images of (a, d, g) Zn4Co1–C/CNT, (b, e, h) Zn1Co1–C/CNT, (c, f, i) Zn1Co4–C/CNT. The

Revealing local structural properties of an atomically thin MoSe₂ surface using optical microscopy

• Lin Pan,
• Peng Miao,
• Anke Horneber,
• Alfred J. Meixner,
• Pierre-Michel Adam and
• Dai Zhang

Beilstein J. Nanotechnol. 2022, 13, 572–581, doi:10.3762/bjnano.13.49

• molybdenum diselenide (MoSe2) flake as surface-enhanced Raman spectroscopy (SERS) platform, we demonstrate the dependency of the Raman enhancement on laser beam polarization and local structure using copper phthalocyanine (CuPc) as probe. Second harmonic generation (SHG) and photoluminescence spectroscopy

• and microscopy are used to reveal the structural irregularities of the MoSe2 flake. The Raman enhancement in the focus of an azimuthally polarized beam, which possesses exclusively an in-plane electric field component is stronger than the enhancement by a focused radially polarized beam, where the out

• -of-plane electric field component dominates. This phenomenon indicates that the face-on oriented CuPc molecules strongly interact with the MoSe2 flake via charge transfer and dipole–dipole interaction. Furthermore, the Raman scattering maps on the irregular MoSe2 surface show a distinct correlation

Influence of thickness and morphology of MoS₂ on the performance of counter electrodes in dye-sensitized solar cells

• Lam Thuy Thi Mai,
• Hai Viet Le,
• Ngan Kim Thi Nguyen,
• Van La Tran Pham,
• Thu Anh Thi Nguyen,
• Nguyen Thanh Le Huynh and
• Hoang Thai Nguyen

Beilstein J. Nanotechnol. 2022, 13, 528–537, doi:10.3762/bjnano.13.44

• was estimated from cross-sectional FE-SEM images. The formation of MoS2 from solutions 2.5 and 5.0 yielded thicknesses of about 50 nm and 500 nm, respectively (Figure 3d,f). The phase structure of the electrodeposited MoS2 thin films was identified by XRD and Raman analyses. The XRD pattern and the

• Raman spectrum of the MoS2 thin film deposited from solution 5.0 are presented in Figure 4. The XRD pattern of the MoS2/FTO samples shows only the peaks of the FTO substrate because the MoS2 thin film is amorphous or too thin (Figure 4a) [22][23][24]. Thus, the electrodeposited thin film was further

• characterized by Raman spectroscopy. The Raman spectrum of the MoS2/FTO sample showed the characteristic peaks of the 2H and 1T phases of MoS2 (Figure 4b). The appearance of the J1, J2, and J3 peaks around 150, 226, and 326 cm−1 confirmed the presence of the 1T metallic phase. Whereas the two Raman vibration

Zinc oxide nanostructures for fluorescence and Raman signal enhancement: a review

• Ioana Marica,
• Fran Nekvapil,
• Maria Ștefan,
• Cosmin Farcău and
• Alexandra Falamaș

Beilstein J. Nanotechnol. 2022, 13, 472–490, doi:10.3762/bjnano.13.40

• , Romania RDI Laboratory of Applied Raman Spectroscopy, RDI Institute of Applied Natural Sciences (IRDI-ANS), Babeş-Bolyai University, Fântânele 42, 400293, Cluj-Napoca, Romania 10.3762/bjnano.13.40 Abstract Since the initial discovery of surface-enhanced Raman scattering (SERS) and surface-enhanced

• as well as on tuning the photoluminescence properties of ZnO nanostructures through combination with metal nanoparticles. This review covers the major recent results of ZnO-based nanostructures used for fluorescence and Raman signal enhancement. The broad range of ZnO and ZnO–metal nanostructures

• noble metal nanoparticles and the molecular fluorescence enhancement in the presence of ZnO alone and in combination with metal nanoparticles are also reviewed. Keywords: fluorescence; surface-enhanced Raman spectroscopy; ZnO–metal nanomaterials; ZnO nanostructures; Introduction Over the last decades

Investigation of electron-induced cross-linking of self-assembled monolayers by scanning tunneling microscopy

• Patrick Stohmann,
• Sascha Koch,
• Yang Yang,
• Christopher David Kaiser,
• Julian Ehrens,
• Jürgen Schnack,
• Niklas Biere,
• Dario Anselmetti,
• Armin Gölzhäuser and
• Xianghui Zhang

Beilstein J. Nanotechnol. 2022, 13, 462–471, doi:10.3762/bjnano.13.39

• electron energy loss spectroscopy (HREELS) [53][54], Raman spectroscopy [55], and low-energy electron microscopy (LEEM) [56] as well as by theoretical analysis [57][58][59]. It is now well established that electron irradiation leads to cleavage of C–H and S–H bonds, followed by the formation of C–C bonds

Tubular glassy carbon microneedles with fullerene-like tips for biomedical applications

• Sharali Malik and
• George E. Kostakis

Beilstein J. Nanotechnol. 2022, 13, 455–461, doi:10.3762/bjnano.13.38

• of these glassy carbon tubules shows long-range order with a d-spacing of 4.89 Å, which is indicative of glassy carbon. Raman spectroscopy shows the material to be graphitic in nature, and SEM shows the fullerene-like structure of the material. This work provides new insights into the structure of

• glassy carbon microneedles Figure 4 shows a typical Raman spectrum of the glassy carbon microneedles. The D-band is at 1352 cm−1, and the G-band is at 1589 cm−1. The D-band, the so-called defect band, originates from a hybridized vibrational mode associated with local defects and disorder. In this case

• local crystalline structure [17]. This is in good agreement with Raman spectrum data for glassy carbon [17][18] and confirms that the carbon microneedles fabricated here are glassy in nature. Figure 5 shows the XRD measurement of the glassy carbon tubules. The single sharp peak is indicative of

A chemiresistive sensor array based on polyaniline nanocomposites and machine learning classification

• Jiri Kroutil,
• Alexandr Laposa,
• Ali Ahmad,
• Jan Voves,
• Vojtech Povolny,
• Ladislav Klimsa,
• Marina Davydova and
• Miroslav Husak

Beilstein J. Nanotechnol. 2022, 13, 411–423, doi:10.3762/bjnano.13.34

• been used for the classification of gas sensor data using a 10-fold cross-validation to reach the highest classification rate. Results and Discussion The sensors layers were investigated by scanning electron microcopy (SEM), Raman spectroscopy, current–voltage and temperature analysis, and gas sensing

• analysis. Further, statistical classification analysis was implemented for the evaluation of target gases. Scanning electron microscopy and Raman spectroscopy The surface morphology and uniformity of additives in PANI of the deposited active layers were examined by scanning electron microscopy (TESCAN

• flakes and WO3 nanowires homogeneously distributed in the layers. Pristine PANI was examined by SEM (Figure 1h) and Raman spectroscopy (Raman spectrometer Renishaw inVia Qontor) at room temperature with 633 nm excitation wavelength (Figure 2). The spectrum of pristine PANI is typical of the emeraldine

Impact of device design on the electronic and optoelectronic properties of integrated Ru-terpyridine complexes

• Max Mennicken,
• Sophia Katharina Peter,
• Corinna Kaulen,
• Ulrich Simon and
• Silvia Karthäuser

Beilstein J. Nanotechnol. 2022, 13, 219–229, doi:10.3762/bjnano.13.16

• was verified by infrared reflection absorption spectroscopy (IRRAS) and surface-enhanced Raman spectroscopy in combination with density functional theory calculations, as well as variable angle spectroscopic ellipsometry. Based on this wire formation protocol the on-chip preparation of Ru(TP)2-complex

• ) (Figure 1). Recently, we showed by evaluation of the IRRAS and Raman spectra of the individual wire growth steps (i)–(iii) and comparison of these spectra to the spectra of bulk model substances that the formation of the Ru(TP)2 complexes was largely successful [19]. However, a detailed investigation of

Cantilever signature of tip detachment during contact resonance AFM

• Devin Kalafut,
• Ryan Wagner,
• Maria Jose Cadena,
• Anil Bajaj and
• Arvind Raman

Beilstein J. Nanotechnol. 2021, 12, 1286–1296, doi:10.3762/bjnano.12.96

• Devin Kalafut Ryan Wagner Maria Jose Cadena Anil Bajaj Arvind Raman School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA 10.3762/bjnano.12.96 Abstract Contact resonance atomic force microscopy, piezoresponse force microscopy, and electrochemical strain microscopy are

Morphology-driven gas sensing by fabricated fractals: A review

• Vishal Kamathe and
• Rupali Nagar

Beilstein J. Nanotechnol. 2021, 12, 1187–1208, doi:10.3762/bjnano.12.88

• experimental approaches. Here, lithography techniques can be implemented to write fractals of different fractal dimensions and their response under identical test conditions can be studied. Such structures can also be explored as substrates for surface-enhanced Raman spectroscopy, which finds applications in

The effect of cobalt on morphology, structure, and ORR activity of electrospun carbon fibre mats in aqueous alkaline environments

• Markus Gehring,
• Tobias Kutsch,
• Osmane Camara,
• Alexandre Merlen,
• Hermann Tempel,
• Hans Kungl and
• Rüdiger-A. Eichel

Beilstein J. Nanotechnol. 2021, 12, 1173–1186, doi:10.3762/bjnano.12.87

• fibres. In this study, cobalt-decorated fibres are prepared, and the influence of carbonisation temperature on the resulting particle decoration, as well as on fibre structure and morphology is discussed. Scanning electron microscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron

• electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, elemental analysis, and inductively coupled plasma optical emission spectrometry (ICP-OES). In addition, the fibres were analysed in terms of their

• only in the binding energy range from 770 to 795 eV. Raman spectra were obtained using a Bruker Senterra at room temperature in ambient atmosphere. The excitation wavelength was 532 nm with a power of 2 mW. The signals of two subsequent measurements of 30 s each were added up, to improve the signal-to

Molecular assemblies on surfaces: towards physical and electronic decoupling of organic molecules

• Sabine Maier and
• Meike Stöhr

Beilstein J. Nanotechnol. 2021, 12, 950–956, doi:10.3762/bjnano.12.71

• significant enhancement of the excited-state spin lifetimes [62]. Concerning optical properties, successful decoupling made the examination of fluorescence from both single molecules and molecular assemblies feasible by tunneling electron excitation [19][63][64][65][66]. Also, sub-molecularly resolved Raman

The role of deep eutectic solvents and carrageenan in synthesizing biocompatible anisotropic metal nanoparticles

• Nabojit Das,
• Akash Kumar and
• Raja Gopal Rayavarapu

Beilstein J. Nanotechnol. 2021, 12, 924–938, doi:10.3762/bjnano.12.69

• -enhanced Raman scattering (SERS) when doped with rhodamine B (RhB). The enhancement factor produced by these gold nanoflowers was estimated to be 1.09 × 105 regarding pure RhB. The value of the enhancement factor is up to par with the intensively branched gold nanoparticles and is even greater than some of

Modification of a SERS-active Ag surface to promote adsorption of charged analytes: effect of Cu²⁺ ions

• Bahdan V. Ranishenka,
• Andrei Yu. Panarin,
• Irina A. Chelnokova,
• Sergei N. Terekhov,
• Peter Mojzes and
• Vadim V. Shmanai

Beilstein J. Nanotechnol. 2021, 12, 902–912, doi:10.3762/bjnano.12.67

• the electrostatic interaction between analyte molecules and silver nanoparticles (Ag NPs) on the intensity of surface-enhanced Raman scattering (SERS). For this, we fabricated nanostructured plasmonic films by immobilization of Ag NPs on glass plates and functionalized them by a set of differently

• ; oligonucleotides; porphyrin; silver nanoparticles; substrate modification; surface-enhanced Raman spectroscopy (SERS); Introduction Surface-enhanced Raman scattering (SERS) with its advantages of extreme sensitivity, high selectivity, and non-destructive nature has demonstrated great potential for the quick

• even technical tasks need to be solved for practical applications of the method [2][3][4]. Raman signal surface enhancement uses so-called SERS-active substrates that are mainly inorganic or hybrid nanostructured materials. Significant attention has been devoted to the development of formation methods

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• 0.2–1.3%) and, within this dose range, measured a metal–insulator transition [19]. Raman analysis showed that even at the highest dose (i.e., for strongly insulating graphene), the crystal lattice structure of the graphene sheet was essentially preserved. A subsequent study by Moktadir et al

• Klein et al., the effects of ion dose on the optical and valleytronic properties of the material were investigated [36]. In this study, Raman spectroscopy was used to systematically probe the effect of increasing disorder for increasing irradiation dose, and the corresponding distance between the ion

• demonstrated, using localized helium ion irradiation followed by encapsulation in hBN in order to enhance the optical quality of the defect states [34]. Results from this study are shown in Figure 2g. A recent study of the effect of helium ion-induced disorder on the Raman modes and photoluminscence behavior

Properties of graphene deposited on GaN nanowires: influence of nanowire roughness, self-induced nanogating and defects

• Jakub Kierdaszuk,
• Piotr Kaźmierczak,
• Justyna Grzonka,
• Aleksandra Krajewska,
• Aleksandra Przewłoka,
• Wawrzyniec Kaszub,
• Zbigniew R. Zytkiewicz,
• Marta Sobanska,
• Maria Kamińska,
• Andrzej Wysmołek and
• Aneta Drabińska

Beilstein J. Nanotechnol. 2021, 12, 566–577, doi:10.3762/bjnano.12.47

• Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/46, 02-668, Warsaw, Poland 10.3762/bjnano.12.47 Abstract We present detailed Raman studies of graphene deposited on gallium nitride nanowires with different variations in height. Our results indicate that different density and height of

• nanowires impact graphene properties such as roughness, strain, and carrier concentration as well as density and type of induced defects. Tracing the manifestation of those interactions is important for the application of novel heterostructures. A detailed analysis of Raman spectra of graphene deposited on

• engineering. Keywords: carrier concentration; gallium nitride; graphene; nanowires; Raman spectroscopy; scattering on defects; strain; Introduction The combination of excellent electrical and mechanical properties with interesting physical phenomena occurring in two-dimensional structures makes graphene an

On the stability of microwave-fabricated SERS substrates – chemical and morphological considerations

• Limin Wang,
• Aisha Adebola Womiloju,
• Christiane Höppener,
• Ulrich S. Schubert and
• Stephanie Hoeppener

Beilstein J. Nanotechnol. 2021, 12, 541–551, doi:10.3762/bjnano.12.44

• , Philosophenweg 7, 07743 Jena, Germany Leibniz-Institut of Photonic Technology e.V. (IPHT), Albert-Einstein-Straße 9, 07745 Jena, Germany Institute of Physical Chemistry, Friedrich Schiller University Jena, Lessingstr. 10, 07743 Jena, Germany 10.3762/bjnano.12.44 Abstract The stability of surface-enhanced Raman

• substrates treated with methanol, ethanol, or N,N-dimethylformamide (DMF) were comparable and showed overall good stability and did not show severe morphological changes or a strong decrease in their Raman activity. Toluene treatment resulted in a strong decrease in the Raman activity whereas dimethyl

• sulfoxide (DMSO) treatment completely preserved or even slightly improved the Raman enhancement capabilities. SERS substrates immersed into phosphate-buffered saline (PBS) solutions were observed to be rather instable in low and neutral pH buffer solutions. Other buffer systems showed less severe influences

Surface-enhanced Raman scattering of water in aqueous dispersions of silver nanoparticles

• Paulina Filipczak,
• Krzysztof Hałagan,
• Jacek Ulański and
• Marcin Kozanecki

Beilstein J. Nanotechnol. 2021, 12, 497–506, doi:10.3762/bjnano.12.40

• Paulina Filipczak Krzysztof Halagan Jacek Ulanski Marcin Kozanecki Department of Molecular Physics, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland 10.3762/bjnano.12.40 Abstract The resonance Raman effect (RRE) is a phenomenon which results in a strong

• selective enhancement of Raman signals from the samples. Previous studies showed that the RRE in liquid water directly corresponds to its supramolecular structure. It was also reported that the electric-field-induced orientation of water molecules on the electrode surface results in the surface-enhanced

• Raman scattering (SERS) effect. In this work, we show the SERS effect for water molecules in the dispersion of silver nanoparticles (AgNPs) without any external electrical field. An enhancement factor was estimated to be (4.8 ± 0.8) × 106 for an excitation wavelength of 514.5 nm and for AgNPs with an

A review on nanostructured silver as a basic ingredient in medicine: physicochemical parameters and characterization

• Gabriel M. Misirli,
• Kishore Sridharan and
• Shirley M. P. Abrantes

Beilstein J. Nanotechnol. 2021, 12, 440–461, doi:10.3762/bjnano.12.36

• ], Copyright 2005 American Chemical Society B; part C was reprinted from [39], Chemical Physics Letters, vol. 427, by J. M. McLellan, A. Siekkinen, J. Chen, Y. Xia, Comparison of the surface-enhanced Raman scattering on sharp and truncated silver nanocubes, 122–126, Copyright (2006), with permission from

Solution combustion synthesis of a nanometer-scale Co₃O₄ anode material for Li-ion batteries

• Monika Michalska,
• Huajun Xu,
• Qingmin Shan,
• Shiqiang Zhang,
• Yohan Dall'Agnese,
• Yu Gao,
• Amrita Jain and
• Marcin Krajewski

Beilstein J. Nanotechnol. 2021, 12, 424–431, doi:10.3762/bjnano.12.34

• Raman spectroscopy (RS) measurements. The experimental results from both techniques are shown in Figure 1 and they are complementary. The XRD pattern presented in Figure 1a reveals seven peaks located at 19°, 31.3°, 36.8°, 38.7°, 44.8°, 55.8°, and 59.4°, which correspond to the (111), (220), (311), (222

• broadening yielded an estimated average crystallite size of about 40 nm, according to the Scherrer formula. The Raman spectrum shown in Figure 1b exhibits five bands located at 184, 464, 506, 601, and 670 cm−1, corresponding to the F2g3, Eg, F2g2, F2g1, and A1g active vibrational modes, respectively [5][10

• Raman spectroscopy (RS). XRD data was acquired using a SIEMENS D500 diffractometer equipped with a Cu Kα (λXRD = 1.542 Å) radiation source. The room-temperature XRD pattern in the range of 15° ≤ 2θ ≤ 60° was collected with a step size of 0.002° and an acquisition time of 3 s per step. The RS experiments

Nickel nanoparticle-decorated reduced graphene oxide/WO₃ nanocomposite – a promising candidate for gas sensing

• Ilka Simon,
• Alexandr Savitsky,
• Rolf Mülhaupt,
• Vladimir Pankov and
• Christoph Janiak

Beilstein J. Nanotechnol. 2021, 12, 343–353, doi:10.3762/bjnano.12.28

• using XPS and Raman spectroscopy. Such bonds can play an important role also in our case with regard to charge transfer. It has been established that adsorption of NO2 molecules will cause upward band bending by capturing free electrons from the conduction band and shift the Fermi level of WO3 away from