In recent years, hybrid manganese(II) halides (HMHs) have attracted wide attention due to their impressive optical properties, low toxicity, and facile synthetic processibility. Being effective reabsorption-free phosphors, these compounds demonstrate the potential to be used as low-cost solution-processable scintillators. However, most of the HMHs studied to date contain bulk organic cations and, as a result, are characterized by low density and low X-ray stopping power.
View Article and Find Full Text PDFHybrid halocuprates(I) are nowadays the subject of intensive studies as promising materials for various optoelectronic applications. This class of materials is characterized by wide structural diversity enabled by a great variety in the size and shape of organic cations. Therefore, the study of composition-structure-property relationships is a key step for the rational design of new halocuprate materials with desired properties.
View Article and Find Full Text PDFThe balance between the mitochondrial respiratory chain activity and the cell's needs in ATP ensures optimal cellular function. Cytochrome c is an essential component of the electron transport chain (ETC), which regulates ETC activity, oxygen consumption, ATP synthesis and can initiate apoptosis. The impact of conformational changes in cytochrome c on its function is not understood for the lack of access to these changes in intact mitochondria.
View Article and Find Full Text PDFOrganic diammonium cations are a promising component of both layered (2D) and conventional (3D) hybrid halide perovskites in terms of increasing the stability of perovskite solar cells (PSCs). We investigated the crystallization ability of phase-pure 2D perovskites based on 1,4-butanediammonium iodide (BDAI2) with the layer thicknesses n = 1, 2, 3 and, for the first time, revealed the presence of a persistent barrier to obtain BDA-based layered compounds with n > 1. Secondly, we introduced BDAI2 salt into 3D lead−iodide perovskites with different cation compositions and discovered a threshold-like nonmonotonic dependence of the perovskite microstructure, optoelectronic properties, and device performance on the amount of diammonium additive.
View Article and Find Full Text PDFIn this study, we systematically investigated the phase diversity and crystallization pathways of the FABr excessive regions of two ternary systems of FABr-PbBr-DMF and FABr-PbBr-DMSO (where FA-formamidinium cations, DMF-dimethylformamide and DMSO-dimethyl sulfoxide solvents). In these systems, a new FAPbBr phase with a structure containing chains of vertex-connected PbBr octahedra is discovered, and its crystal structure is refined. We experimentally assess fundamental information on differences in the mechanisms of crystallization process in FABr-PbBr-DMF and FABr-PbBr-DMSO systems and determine possible pathways of crystallization of hybrid perovskites.
View Article and Find Full Text PDFA scalable procedure of SERS substrates design was developed using a novel plasmonic structure based on a freestanding chitosan film, silver nanoparticles, and graphene oxide. Chitosan provides a uniform distribution of silver nanoparticles from a colloidal suspension and, therefore, a reproducible Raman signal from local areas of measurements of several tens of microns. The addition of graphene oxide (GO) to the colloidal solution of silver nanoparticles suppresses the tortuous background fluorescence signal from the analyte and leads to an increase in the signal-to-fluorescence background intensity ratio by up to 6 times as compared to structures without GO.
View Article and Find Full Text PDFMikrochim Acta
May 2022
A unique approach based on Molecular Immobilization and Resonant Raman Amplification by Complex-Loaded Enhancers (MIRRACLE) on copper (II)-chitosan-modified SERS-active metallic nanostructured substrates is proposed for sensitive and rapid determination of the catecholamines (CA) dopamine, norepinephrine, and epinephrine. The ternary (CA)Cu(4AAP) complexes were characterized by the appearance of new absorbance bands at 555, 600, and 500 nm for dopamine, norepinephrine, and epinephrine, respectively. The new absorbance band matched with a broad surface plasmon resonance band of utilized silver nanoparticles: 450-600 nm, and 633 excitation wavelength.
View Article and Find Full Text PDFWe propose a new, simple, and easily implemented approach to improve the morphology of thin films of lead halide perovskites. A key feature of the approach is the controllable size increase of perovskite grains facilitated by polyiodides formed on the surface of the perovskite upon its treatment with iodine solutions in nonpolar solvents with the best results obtained for iodine solution in toluene saturated with MAI. Such a treatment demonstrated an increase in the average grain size of the films of up to 3.
View Article and Find Full Text PDFSurface-enhanced Raman spectroscopy (SERS) is a promising tool that can be used in the detection of molecular changes triggered by disease development. Cardiovascular diseases (CVDs) are caused by multiple pathologies originating at the cellular level. The identification of these deteriorations can provide a better understanding of CVD mechanisms, and the monitoring of the identified molecular changes can be employed in the development of novel biosensor tools for early diagnostics.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2022
Layered lead halide perovskites (2D LHPs) are attracting considerable attention as a promising material for a new generation of solar cell devices. LHPs have been presented as a more stable alternative to the more widespread 3D bulk perovskite materials; however, a critical analysis of their photostability is still lacking. In this work, we perform a comparative study between BAMAPbI (BA─butylammonium and MA─methylammonium) 2D LHPs with different dimensionalities ( = 1-3) and MAPbI 3D perovskites.
View Article and Find Full Text PDFLayered hybrid halide perovskites (LHHPs) are an emerging type of semiconductor with a set of unique optoelectronic properties. However, the solution processing of high-quality LHHPs films with desired optical properties and phase composition is a challenging task, possibly due to the structural disorder in the LHHP phase. Nevertheless, there is still a lack of experimental evidence and understanding of the nature of the structural disorder in LHHPs and its influence on the optical properties of the material.
View Article and Find Full Text PDFSolution methods remain the most popular means for the fabrication of hybrid halide perovskites. However, the solubility of hybrid perovskites has not yet been quantitively investigated. In this study, we present accurate solubility data for MAPbI, FAPbI, MAPbBr and FAPbBr in the two most widely used solvents, DMF and DMSO, and demonstrate huge differences in the solubility behavior depending on the solution compositions.
View Article and Find Full Text PDFActa Crystallogr E Crystallogr Commun
July 2021
A novel triiodide phase of the formamidinium cation, CHN ·I , crystallizes in the triclinic space group at a temperature of 110 K. The structure consists of two independent isolated triiodide ions located on inversion centers. The centrosymmetric character of I was additionally confirmed by the observed pronounced peaks of symmetrical oscillations of I at 115-116 cm in Raman scattering spectra.
View Article and Find Full Text PDFThe fast progress of lab-scale perovskite solar cells makes the problem of upscaling of perovskite thin-film deposition more and more acute; therefore, the development of new methods for perovskite deposition is highly desired. In this work, we proposed a new solution-free preparation approach for hybrid perovskite films based on the in situ generation of methylammonium iodide from methylamine and iodine vapors in the presence of an organic reducing agent conjugated with a redox process of metallic lead conversion with iodine vapor. At first, we demonstrated that either metallic lead or lead iodide powders can readily react with the solution of methylamine and iodine in the presence of isopropyl alcohol acting as a reducing agent, resulting in a phase-pure polycrystalline CHNHPbI perovskite.
View Article and Find Full Text PDFToxic, carcinogenic, and mutagenic properties of polycyclic aromatic hydrocarbons (PAHs) and environmental pollution caused by polycyclic aromatic sulfur heterocycles (PASHs) postulate the importance of their selective and sensitive determination in environmental and oil fuel samples. Surface-enhanced Raman spectroscopy (SERS) opens up an avenue toward multiplex analysis of complex mixtures, however not every molecule gives high enhancement factors and, thus, cannot be reliably detected SERS. However, the sensitivity can be drastically increased by additional resonant enhancement as a result of the analyte absorption band overlapping with the surface plasmon band of nanoparticles (NPs) and the laser excitation wavelength.
View Article and Find Full Text PDFA new solvent system for PbI based on HI solution in acetone with a low boiling point is proposed. High solubility of PbI is caused by the formation of iodoplumbate complexes, and reaches a concentration of 1.6 M.
View Article and Find Full Text PDFSolutions of methylammonium and formamidinium polyhalides (AX, A = MA, FA, X = I, Br) in isopropanol are introduced as novel versatile precursors for the fabrication of APbX hybrid perovskite thin films via oxidation of metallic Pb. The polyhalide solution with adjustable reactivity is distributed over a metallic Pb layer followed by iodine vapor postprocessing to tune the morphology and composition of the film using only the elements inherently present in the perovskite. This method is easily reproducible in any materials science laboratory with equipment commonly used for perovskite solar cell fabrication and resulted in power conversion efficiencies of 16.
View Article and Find Full Text PDFWe found that laser irradiation, being widely used in perovskite photovoltaics for both laser scribing and materials characterization, inevitably causes a cascade of complex photo- and thermochemical conjugated reactions, material melting, and ablation with deep morphological and composition changes of perovskite thin films over a much larger area compared to the initial laser spot. A crucial issue in the advancing or suppression of these degradation processes is related to the origin of the surrounding atmosphere. In particular, an effective approach utilizing an inert gas flow directed onto the exposed area is suggested for the first time to eliminate the negative consequences of perovskite laser scribing.
View Article and Find Full Text PDFHerein, a silver-chitosan nanocomposite for application in surface enhanced Raman spectroscopy (SERS) sensing was proposed. It was shown that optically transparent chitosan coatings with 0.8 μm thickness allow penetration of target analytes to silver nanoparticles and the analysis in both polar and nonpolar solvents.
View Article and Find Full Text PDFA unique technique for preparation of thin patterned perovskite films is suggested based on an interaction of reactive polyiodide melts with metallic lead coatings using a patterned die with a given relief. The growth of perovskite in confined space results in pin-hole free textured films.
View Article and Find Full Text PDFThe 150th anniversary of the periodic table of elements highlights its tremendous role in chemistry, physics, biology, astronomy, philosophy, and engineering as a shining scientific breakthrough, shedding light on the fundamental laws of nature. Nanoscience and nanotechnology are multidisciplinary, focusing on nanoscale materials and processes, in which a variety of elements are used and single atoms are often manipulated. In this Perspective, we present a new viewpoint on what the renown periodic table can offer to researchers working on nanomaterials.
View Article and Find Full Text PDFNewly discovered methylammonium polyiodides (MAI) are unique precursors for innovative solvent-free technologies in perovskite photovoltaics because MAI are liquids at room temperature and demonstrate high chemical reactivity. We investigated the features of an MAI-I system and built up a first phase diagram in wide temperature and composition ranges using data from differential scanning calorimetry, single-crystal X-ray diffraction, and visual thermal analysis. The phase diagram has been found to differ drastically from that of any related systems owing to the unique propensity of methylammonium toward forming a diversity of polyiodides with complicated crystal structures, namely, MAI, MAI, MAI, and MAI, found in this system for the first time.
View Article and Find Full Text PDFDespite tremendous progress in efficiency and stability, perovskite solar cells are still facing the challenge of upscaling. Here we present unique advantages of reactive polyiodide melts for solvent- and adduct-free reactionary fabrication of perovskite films exhibiting excellent quality over large areas. Our method employs a nanoscale layer of metallic Pb coated with stoichiometric amounts of CHNHI (MAI) or mixed CsI/MAI/NHCHNHI (FAI), subsequently exposed to iodine vapour.
View Article and Find Full Text PDFComposites of WS nanotubes (NT-WS ) and gold nanoparticles (AuNPs) were prepared using aqueous HAuCl solutions and subjected to surface analysis. The obtained materials were jointly characterized by X-ray photoelectron (XPS), Raman scattering (RSS), and ultraviolet photoelectron (UPS) spectroscopies. Optical extinction spectroscopy and electron energy loss spectroscopy in the scanning transmission electron microscopy regime (STEM-EELS) were also employed to study plasmon features of the nanocomposite.
View Article and Find Full Text PDFTransition metal dichalcogenide materials have recently been shown to exhibit a variety of intriguing optical and electronic phenomena. Focusing on the optical properties of semiconducting WS2 nanotubes, we show here that these nanostructures exhibit strong light-matter interaction and form exciton-polaritons. Namely, these nanotubes act as quasi 1-D polaritonic nano-systems and sustain both excitonic features and cavity modes in the visible-near infrared range.
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