Human colorectal tissues obtained by ten cancer patients have been examined by multiple micro-Raman spectroscopic measurements in the 500-3200 cm-1 range under 785 nm excitation. Distinct spectral profiles are recorded from different spots on the samples: a predominant 'typical' profile of colorectal tissue, as well as those from tissue topologies with high lipid, blood or collagen content. Principal component analysis identified several Raman bands of amino acids, proteins and lipids which allow the efficient discrimination of normal from cancer tissues, the first presenting plurality of Raman spectral profiles while the last showing off quite uniform spectroscopic characteristics. Tree-based machine learning experiment was further applied on all data as well as on filtered data keeping only those spectra which characterize the largely inseparable data clusters of 'typical' and 'collagen-rich' spectra. This purposive sampling evidences statistically the most significant spectroscopic features regarding the correct identification of cancer tissues and allows matching spectroscopic results with the biochemical changes induced in the malignant tissues.

Structural and electronic properties of the air-stable Cs2SnI6 defect perovskite have been investigated by applying Raman and photoluminescence spectroscopies in a temperature range of 83 to 433 K. Upon increasing the temperature, the internal Sn-I Raman bands weakly shift to lower energy and broaden. Interestingly, vibrations of Cs atoms against the SnI6 octahedra are only observed above 293 K, activated by the dynamic lattice anharmonicity. Such lattice modes potentially influence charge-carrier mobilities as well as thermal conductivity of the materials. Intriguing emission properties are also observed with very strong (but not uniform) photoluminescence signals that present high-energy shifts on temperature. Copyright (C) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Confer-ences & Exhibition on Nanotechnologies, Organic Electronics & Nanomedicine - NANOTEXNOLOGY 2021.

Air-stable, vacancy-ordered double perovskites Cs2SnX6 (X = Cl, Br, I) have been attracting particular interest due their potential applications in solar cells and thermoelectrics based on their favorable structural, optical and transport properties. In this work, a comprehensive Raman investigation of Cs2SnX6 perovskites is performed over an extended temperature range of 83-433 K in order to provide insight to their lattice dynamics. Substitution of the lighter and more electronegative Cl halogens with the heavier bromide and iodide ones resulted in the decrease of the frequencies for all Raman modes comprising the internal vibrations in the SnX6 octahedra and the nu L(F2g) mode due to Cs vibrations against SnX6 in the rigid lattice. Blue shift and narrowing of the SnX6 stretching and bending bands was invariably observed for all halogen analogues with temperature decrease, evidencing the presence of lattice anharmonicity. More importantly, the elusive nu L(F2g) phonon was only observed for Cs2SnCl6 for all temperatures, complying with the predictions of Hirshfeld surface analysis for the enhanced Cs-SnCl6 interactions. The latter mode emerged for Cs2SnI6 only above room temperature, indicating that combination of anharmonic lattice dynamics with the increased Cs-SnI6 oscillation energy upon increasing temperature may activate this specific "lattice mode", which in the limit of very weak Cs-I interaction ap-proaches the "rattling" Cs vibrations in the cuboctahedral cage. Strong lattice anharmonicity for the chemically stable Cs2SnX6 compounds can be accordingly inferred, which is a key aspect for their performance in future optoelectronic and thermoelectric applications.

Hybrid organic–inorganic FAPbX₃ perovskites (FA = NH₂CHNH₂⁺, X = Cl–, Br–, I–) are currently intensively investigated in solar cells. In this study, off-resonance Raman and far-IR absorption spectra of all single-halogen FAPbX₃, as well as of mixed-halogen FAPbBr₂X derivatives, are reported and analyzed. Vibrations of the PbX₆ octahedra and librations of the FA cation lay at frequencies below 250 cm–¹, while external and internal FA bands are identified above 200 cm–¹. An increase in the frequencies of most vibrational bands is observed upon substituting lighter and more electronegative halides for heavier ones due to strengthening of the electrostatic interaction between X– and the FA NH₂⁺ groups. Variable-temperature Raman measurements are also carried out for FAPbBr₃ and FAPbCl₃ in the 77–400 K range. Upon cooling, the three Pb–X Raman vibrations of the cubic structure, split into eight separate bands, signaling the transformation to the tetragonal phase at ∼240 K and ∼200 K for FAPbBr₃ and FAPbCl₃, respectively. At even lower temperatures, a successive phase transformation to low symmetry orthorhombic phases is evidenced. These temperature-induced effects are accompanied by intense narrowing, soft-mode behavior, and/or sudden frequency shift of specific Raman bands, attributed to ordering of the FA cation.

Nitrogen and fluorine co-doped TiO 2 films have been prepared by dip coating of a modified titania sol-gel based on a nitrogen precursor and a nonionic fluorosurfactant as pore template and fluorine source. The modified NF-TiO 2 films absorb in the visible spectral range, between 400–510 nm and undergo reversible hydrophilic conversion under visible light to a final contact angle of 8°, in contrast to the UV limited optical response of their undoped anatase TiO 2 analogues. The phenomenon takes place at a rate slower than the corresponding one observed for the UV stimulated superhydrophilic effect. The wetting response of the N-F doped TiO 2 films correlates well with the variation of their optical properties and surface morphological characteristics and most importantly with their photocatalytic activity, rendering these materials very promising for self-cleaning applications under visible light.

Herein, we introduce the sensitization of the titania compact layer via the triphenylamine-based metal-free organic (E)-3-(5-(4-(bis(2',4'-dibutoxy-[1,1'-biphenyl]-4yl) amino) phenyl) thiophen-2yl)-2-cyanoacrylic acid (D35) dye, as a totally novel strategy to modify the titania compact layer/perovskite interface and improve the stability of planar Perovskite Solar Cells (PSCs). For this purpose, we fabricated PSCs with the following configuration: FTO/TiO2/CH3NH3PbI3/spiroOMeTAD/Ag as the control device and FTO/TiO2/D35/CH3NH3PbI3/spiro-OMeTAD/Ag as the sensitized one, and subjected them at thermal stress at 100C. The dye-sensitized devices showed an obvious enhancement in terms of thermal stability, since after 60 min of annealing at 100C, the spectroscopic properties of the perovskite films grown upon TiO2/D35 remained practically intact, while the perovskite layer of the control device, began to deteriorate and extended lead iodide areas appeared as a signal of severe degradation. As a result, the photovoltaic performance of the reference PSCs was severely decreased, contrary to the D35-sensitized ones that preserved 70% of their initial efficiency. INTRODUCTION Perovskite solar cells (PSCs) of general formula ABX3 (where A is an organic/inorganic cation, B is a metal cation, and X is a halide anion) are characterized by low-cost fabrication methods[1,2] and high power conversion efficiencies (PCEs) which raised from 3.8% to 24.2% in only a few years of development[3-8]. The chemical and environmental instability of PSCs is one of the main reasons that prevent them from broad commercialization, thus fabrication of stable perovskite crystals is a giant step towards implementation of large scale applications. In this context, stability against thermal strain is one of the tests that PSCs should successfully undergo, since it is well established that photovoltaic protocols aspiring to enter into the production line, should be stable when operating at 80C under 1 sun illumination (100 mWcm) for more than 1000h [9-14]. Therefore, further investigation and improvement upon PSCs is required, in order to develop highly performing devices for practical applications [15-16].

Department of Physics, National Technical University of Athens, 15780, Athens, Greece Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 15341, Agia Paraskevi Attikis, Athens, Greece Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States Department of Chemistry and Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, WA 99164, United States Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China

Amorphous, as shown by X-ray diffraction measurements, MoS2 films (a-MoS2) were deposited by heating a molybdenum wire at temperatures between 500 and 700 degrees C in H2S at 1 Torr. As shown by Scanning Electron Microscopy measurements, the morphology of samples depends significantly on the filament temperature; at low temperature samples are homogeneous and smooth, at intermediate temperatures they exhibit a granular microstructure and at high temperatures a columnar one. X-ray photoelectron spectroscopy measurements have shown S/Mo ratios in films varying between 2.5 and 1.5 dependent on filament temperature. Films also contain oxygen at atomic contents of 8 to 12 %. As shown by XPS and Raman spectroscopy, at a filament temperature of 600 degrees C films are mainly composed of MoS2 also containing oxygen at an atomic ratio of 8%. Spectroscopic ellipsometry measurements made on a-MoS2 films have shown that their band gap is of the order of 1.4 eV, slightly higher than that for the bulk crystalline material. Photoluminescence spectroscopy measurements have shown that samples exhibit a doublet of peaks at 2.8 and 3 eV blue shifted relatively to MoS2 samples composed of one or two mono-layers. The above indicate that the electronic structure of crystalline atomic-layer thick MoS2 is preserved in a-MoS2 films. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Corrosion and Protection Centre, School of Manchester, M13 9PL, UK. E-mail: igor.mol Division of Physical Chemistry, Institute Processes, Nanotechnology and Microsyst 15310 Aghia Paraskevi Attikis, Athens, Gree Separation Technology Group, Department Eindhoven University of Technology, Den Netherlands IoLiTec, Ionic Liquids Technologies Gmb Germany † Electronic supplementary informa 10.1039/c5ra01097g Cite this: RSC Adv., 2015, 5, 35181

Three 1-alkyl-3-methylimidazolium tricyanomethanide (TCM) ionic liquids (ILs) (alkyl = ethyl, butyl and hexyl) and one butyrolactam cation-based IL with a fluorinated anion were synthesised and tested in contact with mild steel (MS) at temperatures up to 80 °C. The corrosion behaviour was evaluated by monitoring the morphological changes on the steel surface after testing. Exposure of MS to the IL results in two main types of degradation that depend on the IL type. General etching over the macroscopic surface of the alloy was revealed for the IL with the fluorinated anion. The 1-alkyl-3-methylimidazolium TCM ILs promoted dissolution of MnS inclusions present in the steel. In the ILs with a shorter alkyl chain in the cation (alkyl = ethyl, butyl), the dissolution of MnS was accompanied by generation of corrosion products around the inclusion sites, which are mainly identified as magnetite and maghemite ferrites by micro-Raman spectroscopy. The rest of the macroscopic steel surface remains unaffected. Etching resulted in significant weight loss due to removal of material, whereas no significant weight loss was revealed following MnS dissolution. Butyrolactam cation-based IL severely attacks MS with the formation of a plethora of corrosion products including ferrites (mainly hematite), zinc oxide, sulphates and carbonates. Addition of 500 ppm sodium molybdate to the butyrolactam cation-based IL resulted in efficient inhibition of etching at both room temperature and 60 °C due to adsorption of molybdate on the alloy surface. A side effect of MS degradation is that the CO2 absorption capacity of the ILs can be severely reduced through the transfer of metal ions and corrosion products from the metallic surface to the liquid phase. Therefore, gravimetric CO2 absorption capacity and kinetic measurements on the selected 1-alkyl-3-methylimidazolium tricyanomethanide ILs before and after their contact with MS were also conducted with the purpose to unveil and study these side effects. Moreover, CO2 absorption experiments of the butyrolactam cation-based IL before and after contact with MS, as well as in the presence of a sodium molybdate inhibitor, showed that sodium molybdate has the capacity to limit significantly the etching rate without affecting the CO2 capture performance of the IL.

Robust Dye Sensitized Solar Cells have been prepared employing liquid electrolytes using ethyl isopropyl sulfone (EiPS) high boiling point solvent. The cells were tested for their durability under harsh thermal stressing conditions of 85 °C and prolonged ageing time, 3000 h in the dark. The use of EiPS outperforms stability-wise the typical methoxypropionitrile MPN solvent, improving the cell stability from 38 to 75%. For both solvents, the physicochemical analysis infers the thermal degradation of the cell with the main changes occurring in the first 300 h of ageing. This was attributed to partial triiodide loss which reduces short circuit photocurrent and leads to formation of luminescent species in the electrolyte that affects the TiO2 surface and reduces open circuit photovoltage. The degradation effects were notably supressed by the use of the more stable EiPS solvent, where it was possible to optimize the iodine content in the redox mediator. It has been thus confirmed that iodine concentration as low as 0.05 M in the EiPS electrolyte is slightly preferable in terms of stability and device performance, comparing with higher concentrations, 0.1 and 0.15 M, respectively.

Waste lignocellulosic biomass can be considered as a residual agro-industrial by-product with more representative species straw, cob, and husk because of their abundance in most countries. Lignocellulosics can be used as natural adsorbents for dyes, heavy metal salts and hydrocarbons in wastewater, seawater, rivers and lakes. The modification of lignocellulosic waste biomass can provide relatively low-cost adsorbents with increased sorption capacity and biodegradability, appropriate for the removal of dyes, heavy metal salts and oil spills from aquatic media. This work deals with the laboratory scale experimental design and execution of tests on the surface of original and modified wheat straw adsorbent, using Brunauer–Emmett–Teller (BET) specific surface area analyzer, Micro-Raman spectroscopy, Fourier transform infrared (FT-IR) and X-ray diffraction analysis (XRD). For the evaluation of microporocity of the highly heterogeneous adsorption materials, appropriate non-destructive spectroscopic techniques were used, as BET using nitrogen and Scanning Electron Microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). Key-Words: waterbodies pollution, adsorption, experimental design, wheat straw, oil spill, BET, FT-IR, XRD, Raman. 1 Introductory Analysis Waste lignocellulosic biomass is natural adsorbent for dyes, heavy metal salts and hydrocarbons from wastewater, seawater, rivers and lakes [1]. Moreover, the thermochemical treatment of lignocellulosic waste biomass can provide low-cost adsorbents with increased sorption capacity and high biodegradability and for removing dyes [2, 3], heavy metals [4] and oil spills [5, 6] from different aquatic environments. Straws are renewable raw materials for production of cellulose, glucose, bioethanol and other chemicals. Straws are often used for dyes, heavy metals and hydrocarbon spills removal. In this case, the surface properties of straws play a crucial role. Since leaves and stems are the main components of straw, the surface of these plant parts should be considered in order to understand the relevant adsorption parameters, as they appear in the corresponding simulation models. More specifically, this capacity depends primarily on the chemical composition structure of straw tissue that has direct contact with oil. The adsorption capacity depends heavily on the structure of the straw stalks in the bundles, the distances between them, the diameter and cross-sections of each stalk and leaf [7]. A large number of lignocellulosic materials, like walnut shell [1], biomass [8], raw bagasse [9], carbonized pith bagasse [10], acetylated sugarcane bagasse [11] , peat [12, 13], fatty acid grafted sawdust [14], carbonized fir fibers [15], barley straw [9, 10, 16-20], wheat straw [21, 22], rice straw [23], rice husk [24-25], sludge, garlic and onion peels Recent Advances in Energy, Environment and Financial Planning ISBN: 978-960-474-400-8 74 [26], and banana trunk fiber [27], can be used as adsorbents. In this work the surface of wheat straw, a lignocellulosic biomass adsorbent, before and after chemical modification by autohydrolysis [28], was studied under laboratory conditions, by carrying out BET, Raman spectroscopy, XRD, FT-IR, and SEM with EDS. 2 Materials and Methods The wheat straw used in this work was obtained from the Kapareli village, close to the Thiva city at the Kopaida area in central Greece (harvesting year 2012), as a suitable source for full-scale industrial applications. The moisture content of the material when received was 8.8% w/w; after screening, the fraction with particle sizes between 10 and 20 mm was isolated. The autohydrolysis process was performed in a 3.75-L PARR 4843 batch reactor. The isothermal hydrolysis time was 10 min (not including the nonisothermal preheating and cooling periods). The reaction was catalyzed by the organic acids that were produced by wheat straw during autohydrolysis at a liquid-to-solid ratio of 20:1. The volume of the liquid phase (water) was 2000 mL and the solid material dose (wheat straw) was 100 g (i.e., 91.25 g on dry basis). The stirring speed was 50 rpm. The reaction ending temperature of 200°C was reached after 60 min of preheating [5, 28]. The surface areas and porosity of the powders were determined by the Brunauer-Emmet-Teller (BET) method [29]. Liquid nitrogen isotherms at 77 K were obtained, using the Autosorb-1 MP (Quantachrome) porosimeter. Before each measurement, the samples were degassed, under high vacuum 10 mbar for 24 h, at 353K in the outgassing stations of the instrument. The selected program of relative pressures covered all the pore sizes from the ultra-micropore to the large mesopores region (1x10<=P/Po<1).The tolerance and equilibration time of all the pressure points were set to 0 and 10 respectively. Before performing the measurements, all samples were turned into powders using a hummer mill. The Raman spectra [30] of the samples were recorded on a Renishaw inVia Reflex spectrometer in backscattering configuration employing a near infrared (NIR) diode laser (λ =785 nm) as excitation source. Rayleigh scattering was rejected with a 100 cm cut-off dielectric edge filter, and analysis of the scattered beam was performed on a 250 mm focal length spectrometer along with a 1200 lines/mm diffraction grating and a high-sensitivity chargecoupled device (CCD detector). The intensity of laser was set at 0.5 mW/μm. Subtraction of the luminescence background (%) was performed for the wavenumbers range between 120 and 1700 cm. Raman spectra analysis has been performed by a polynomial fitting interpolation routine, while spectral deconvolution has been carried out by nonlinear least-squares fitting of the Raman peaks to a mixture of Lorentzian and Gaussian line shapes, providing the peak position, width, height, and integrated intensity of each Raman band. IR spectra [31] were collected on a Thermo Scientific Nicolet 6700 FTIR with N2 purging system. Spectra were acquired using a single reflection ATR (attenuated total reflection) SmartOrbit accessory equipped with a singlebounce diamond crystal (spectral range: 10,000–55 cm, angle of incidence: 45◦). A total of 32 scans were averaged for each sample and the resolution was 4 cm. The spectra were obtained against a single-beam spectrum of the clean ATR crystal and converted into absorbance units. Data were collected in the range 4000–400 cm. The powder XRD patterns of the origin and the pretreated samples were measured by a SIEMENS D5005 X-Ray Diffractometer using Ni-filtered CuKa (λ=0.154 nm) radiation at 45 kV and 40 mA and continuous scan mode. The XRD patterns were recorded in the scan range 2θ=5-70 , at scan rate step=0.04 , dwell time=3 sec, i.e. total scan time approximately 1 h and 30 min. The study of untreated and pretreated wheat straw samples by scanning electron microscopy (SEM) was conducted using an FEI INSPECT SEM equipped with an EDAX super ultra thin window analyzer for energy dispersive X-ray spectroscopy (EDS). The SEM analysis was performed in low vacuum operation mode (P=0.53 Torr) in order to avoid charging effects. The magnification was X750, X2,500, X7,500 and X20,000. 3 Results and Discussion The adsorption capacity of straw depends upon porosity, as well as chemical reactivity of functional groups at the adsorbent surface. The BET isotherms are given in Fig. 1 for (a) untreated and (b) modified wheat straw samples. The pore size distribution resulted from these BET isotherms is presented in Fig. 2. The BET values range were 3.0 to 3.1 m/g (see Table 1). Following the analysis of the results obtained by N2 adsorption porosimetry on untreated and autohydrolyzed wheat straw, we were able to compare the properties (BET surface area, total pore Recent Advances in Energy, Environment and Financial Planning ISBN: 978-960-474-400-8 75 volume and mean pore diameter) for each of the samples. It is clear that pretreatment causes the increase in the mean pore diameter from 17.5 to 29.7 nm and total pore volume from 0.013 to 0.023 mL/g. The higher value of total pore volume is observed on the modified material. This imposes the most profound changes on the material, something that was also confirmed by Raman spectra (Fig. 3) and FT-IR spectroscopy (Figs. 5-8). On the contrary, besides the fact that the hydrothermal treatment has an effect on the mean pore diameter (Table 1), the pore size distribution does not present a significant change (see Fig. 2). In Fig. 4, the XRD pattern of original/raw and treated/autohydrolyzed wheat straw shows a higher crystallinity as regards the cellulose of pretreated sample. FT-IR spectroscopy was applied to identify the functional groups responsible for Methylene Blue (MB) sorption (See Fig. 5). The spectra indicate the band at around 1050 cm, which is attributed to CO stretching of the methoxy group (-OCH3) of the aromatic ring of lignin or to the C-O bonds of cellulose / hemicelluloses constituents (see Table 2). Other hydroxyl groups and carboxyl groups (i.e., phenolic, aliphatic extractives), also negatively charged, could be involved in the sorption of MB via electrostatic interaction. Carboxyl and hydroxyl groups were identified as the most important groups responsible for the sorption of MB [32, 33]. The higher MB sorption observed could be attributed to the higher lignin content and the difference in water extractives which contain tannins, i.e., OH groups [34]. Peaks at about 1600 cm, 1400 cm, 1350 cm 1 and 890 cm are characteristic bands of the MB spectrum. For both samples, untreated and pretreated wheat straw, the observed trend was the same: (i) Reduction of dominant peaks (3400 from the OH stretching of phenol group and 2900 cm from the CH stretching of methyl group) associated with the Cr(VI) load (see Fig. 6 and Table 2); these phenomena show that a metal binding process is taking place at the surface of the adsorbents. (ii) Elimination of peaks indicating that surface –OH group is one o

Visible light active ultrafiltration (UF) membranes coated with modified nanostructured titania (m-TiO2) were for the first time developed using a sol-gel preparation technique combined with a dip-coating deposition procedure. It has been confirmed that the structural, morphological and physicochemical properties of the modified titania membranes strongly depend on the dip-coating and calcination rates. The modified membranes were incorporated in a water purification photocatalytic reactor in continuous flow filtration conditions and tested for the photocatalytic degradation of azo-dye model compounds (namely methyl orange - MO and methylene blue - MB) with very promising results. The photocatalytic experiments took place under ambient operating temperature and low pressure without any compromise on the efficiency of the membrane's permeate flux. Without irradiation, the permeability drops with increasing flow rates of the solution that is forced to penetrate through their pore structure. The photocatalytic efficiency depends on the effluent flow rate however, under both UV and visible light, the permeability was continuously increasing due to the photoinduced hydrophilicity effect. Compared to MO, the MB pollutant was degraded at much higher rate due to its better adsorption, independently of the type of the membrane. The permeability of the membranes increases with the volume treated due to the wettability of the m-TiO2 treated membrane, rendering the need for regeneration or anti-fouling procedures unnecessary and making the process more energy efficient. Due to the low temperature function and the photoinduced hydrophilic effect of the modified TiO2 photocatalytic UF membranes, the photocatalytic reactor can efficiently work without any extra device, fact that leads to low installation and operating costs and provides an energy efficient procedure of cleaning polluted aqueous solutions. (C) 2013 Elsevier B.V. All rights reserved.

Waste lignocellulosic biomass is an abandoned agro-industrial by-product including wheat straw, barley straw, spruce sawdust, pine sawdust, corn stover, sugarcane bagasse, etc. Lignocellulosics can be used as natural adsorbents for dyes, heavy metals and hydrocarbons in wastewater, seawater, rivers and lakes. The thermochemical modification of lignocellulosic waste biomass can provide relatively low-cost adsorbents with increased sorption capacity and biodegradability, appropriate for the removal of chemicals, heavy metals and oil spills from aquatic media. This work deals with the design and performance of measurements on the surface of original and modified wheat straw and spruce sawdust adsorbents, using Brunauer Emmett Teller (BET) specific surface area analyser, Fourier transform infrared (FT-IR) and Micro-Raman spectroscopy. For the evaluation of microporocity of the materials, non-destructive spectroscopic techniques were used, as Liquid Nitrogen Porosimetry and Scanning Electron Microscopy (SEM), which were proved appropriate for the study of highly heterogeneous solid samples.

•Quantum dot sensitized solar cells based on combined semiconductors.•Optimal combination of CdS, CdSe and ZnS.•Micro-Raman, DRS and Photocurrent study of cell stability.•Innovative cell structure providing liberty in design.•Use of inexpensive Cu2S/brass counter electrode.