Showing papers on "Iodide published in 2015"
TL;DR: An approach for depositing high-quality FAPbI3 films, involving FAP bI3 crystallization by the direct intramolecular exchange of dimethylsulfoxide (DMSO) molecules intercalated in PbI2 with formamidinium iodide is reported.
Abstract: The band gap of formamidinium lead iodide (FAPbI3) perovskites allows broader absorption of the solar spectrum relative to conventional methylammonium lead iodide (MAPbI3). Because the optoelectronic properties of perovskite films are closely related to film quality, deposition of dense and uniform films is crucial for fabricating high-performance perovskite solar cells (PSCs). We report an approach for depositing high-quality FAPbI3 films, involving FAPbI3 crystallization by the direct intramolecular exchange of dimethylsulfoxide (DMSO) molecules intercalated in PbI2 with formamidinium iodide. This process produces FAPbI3 films with (111)-preferred crystallographic orientation, large-grained dense microstructures, and flat surfaces without residual PbI2. Using films prepared by this technique, we fabricated FAPbI3-based PSCs with maximum power conversion efficiency greater than 20%.
5,458 citations
TL;DR: High efficiency perovskite solar cells were fabricated reproducibly via Lewis base adduct of lead(II) iodide through interaction between Lewis base DMSO and/or iodide and Lewis acid PbI2 through spin-coating of a DMF solution.
Abstract: High efficiency perovskite solar cells were fabricated reproducibly via Lewis base adduct of lead(II) iodide. PbI2 was dissolved in N,N-dimethyformamide with equimolar N,N-dimethyl sulfoxide (DMSO) and CH3NH3I. Stretching vibration of S═O appeared at 1045 cm–1 for bare DMSO, which was shifted to 1020 and 1015 cm–1 upon reacting DMSO with PbI2 and PbI2 + CH3NH3I, respectively, indicative of forming the adduct of PbI2·DMSO and CH3NH3I·PbI2·DMSO due to interaction between Lewis base DMSO and/or iodide (I–) and Lewis acid PbI2. Spin-coating of a DMF solution containing PbI2, CH3NH3I, and DMSO (1:1:1 mol %) formed a transparent adduct film, which was converted to a dark brown film upon heating at low temperature of 65 °C for 1 min due to removal of the volatile DMSO from the adduct. The adduct-induced CH3NH3PbI3 exhibited high charge extraction characteristics with hole mobility as high as 3.9 × 10–3 cm2/(V s) and slow recombination rate. Average power conversion efficiency (PCE) of 18.3% was achieved from 41 ...
1,960 citations
TL;DR: In this paper, it was shown that the color change results from silver oxidation to silver iodide, due to a reaction with iodine in methyl ammonium lead perovskite, and the change in X-ray diffraction and Xray photoelectron spectroscopy was discussed.
Abstract: Silver is a low-cost candidate electrode material for perovskite solar cells. However, in such cells the silver electrodes turn yellow within days of device fabrication. The color change is also accompanied by a dramatic decrease in the power conversion efficiency when compared to otherwise identical devices using gold electrodes. Here, it is shown that the color change results from silver oxidation to silver iodide, due to a reaction with iodine in methyl ammonium lead perovskite. The change in X-ray diffraction and X-ray photoelectron spectroscopy is discussed. Exposure to air accelerates corrosion of the Ag electrodes when compared to dry nitrogen gas exposure. However, iodine not reacted with silver is observed by X-ray photoelectron spectroscopy even for the perovskite solar cell kept in dry nitrogen gas. It is proposed that silver iodide is formed when methyl ammonium iodide migration is facilitated by the small pinholes in the hole transport layer spiro-MeOTAD.
613 citations
TL;DR: The results show that employing a mixture of MAI and FAI in films deposited via a two-step approach, where the MAI content is <20%, results in the exchange of FA molecules with MA without any significant lattice shrinkage, and with temperature-dependent X-ray diffraction that the trigonal phase exhibits no phase changes in the temperature range studied.
Abstract: Formamidinium lead iodide (FAPbI3) has the potential to achieve higher performance than established perovskite solar cells like methylammonium lead iodide (MAPbI3), while maintaining a higher stability. The major drawback for the latter material is that it can crystallize at room temperature in a wide bandgap hexagonal symmetry (P63mc) instead of the desired trigonal (P3m1) black phase formed at a higher temperature (130 °C). Our results show that employing a mixture of MAI and FAI in films deposited via a two-step approach, where the MAI content is <20%, results in the exchange of FA molecules with MA without any significant lattice shrinkage. Additionally, we show with temperature-dependent X-ray diffraction that the trigonal phase exhibits no phase changes in the temperature range studied (25 to 250 °C). We attribute the stabilization of the structure to stronger interactions between the MA cation and the inorganic cage. Finally, we show that the inclusion of this small amount of MA also has a positive...
456 citations
TL;DR: In situ X-ray scattering data is used to study isothermal transformations of perovskite films derived from chloride, iodide, nitrate, and acetate lead salts and suggests that careful choice of the lead salt will aid in controlling crystal growth, leading to superior films and better performing solar cells.
Abstract: Methylammonium lead halide perovskite solar cells continue to excite the research community due to their rapidly increasing performance which, in large part, is due to improvements in film morphology. The next step in this progression is control of the crystal morphology which requires a better fundamental understanding of the crystal growth. In this study we use in situ X-ray scattering data to study isothermal transformations of perovskite films derived from chloride, iodide, nitrate, and acetate lead salts. Using established models we determine the activation energy for crystallization and find that it changes as a function of the lead salt. Further analysis enabled determination of the precursor composition and showed that the primary step in perovskite formation is removal of excess organic salt from the precursor. This understanding suggests that careful choice of the lead salt will aid in controlling crystal growth, leading to superior films and better performing solar cells.
318 citations
TL;DR: In this paper, the structural and optical properties of the materials formed when a range of compositions of methylammonium iodide and lead iodide were reacted at temperatures from 40 to 190 °C.
Abstract: A delicate control of the stoichiometry, crystallographic phase, and grain structure of the photoactive material is typically required to fabricate high-performance photovoltaic (PV) devices. Organo-metal halide perovskite materials, however, exhibit a large degree of tolerance in synthesis and can be fabricated into high efficiency devices by a variety of different vacuum and solution-based processes, with a wide range of precursor ratios. This suggests that the phase field for the desired material is wider than expected or that high device efficiency may be achieved with a range of phases. Here, we investigate the structural and optical properties of the materials formed when a range of compositions of methylammonium iodide (MAI) and lead iodide (PbI2) were reacted at temperatures from 40 to 190 °C. The reactions were performed according to a commonly employed synthetic approach for high efficiency PV devices, and the data was analyzed to construct a pseudobinary, temperature-dependent, phase-compositio...
217 citations
TL;DR: The whole process of the lead perovskite synthesis consists of a series of equilibria driven by reversible solvent participation involving a polymeric strip of plumbate(II) oligomer as a key intermediate, which will help to rationalize the photovoltaic device studies that have so far remained empirical and to open a new venue to a developing field of microscale lead pervskite devices.
Abstract: Despite tremendous progress in optoelectronic devices using lead perovskite (CH3NH3+PbI3–), there has been a paucity of mechanistic information on how photoactive micron-sized crystals of lead perovskite grow from a mixture of a layered crystal of lead(II) iodide and methylammonium iodide mediated by a polar solvent, DMSO or DMF. We report here that the whole process of the lead perovskite synthesis consists of a series of equilibria driven by reversible solvent participation involving a polymeric strip of plumbate(II) oligomer as a key intermediate. A significant finding includes quick decomposition of perovskite crystal upon exposure to DMSO or DMF at room temperature, where the solvent molecules act as a base to remove acidic ammonium iodide from the perovskite crystal. This observation accounts for the difficulty in controlling perovskite solar cell fabrication. Overall, the polar solvent is indispensible first to degrade a 2-D sheet of crystals of lead(II) iodide into 1-D fibrous intermediates and th...
213 citations
TL;DR: In this article, a novel phosphorus-containing porous polymer is efficiently prepared from tris(4-vinylphenyl)phosphane by radical polymerization, and it can be easily ionized to form an ionic porous polymer after treatment with hydrogen iodide.
Abstract: A novel phosphorus-containing porous polymer is efficiently prepared from tris(4-vinylphenyl)phosphane by radical polymerization, and it can be easily ionized to form an ionic porous polymer after treatment with hydrogen iodide. Upon ionic exchange, transition-metal-containing anions, such as tetrathiomolybdate (MoS4 2−) and hexacyanoferrate (Fe(CN)6 3−), are successfully loaded into the framework of the porous polymer to replace the original iodide anions, resulting in a polymer framework containing complex anions (termed HT-Met, where Met = Mo or Fe). After pyrolysis under a hydrogen atmosphere, the HT-Met materials are efficiently converted at a large scale to metal-phosphide-containing porous carbons (denoted as MetP@PC, where again Met = Mo or Fe). This approach provides a convenient pathway to the controlled preparation of metal-phosphide-loaded porous carbon composites. The MetP@PC composites exhibit superior electrocatalytic activity for the hydrogen evolution reaction (HER) under acidic conditions. In particular, MoP@PC with a low loading of 0.24 mg cm−2 (on a glass carbon electrode) affords an iR-corrected (where i is current and R is resistance) current density of up to 10 mA cm−2 at 51 mV versus the reversible hydrogen electrode and a very low Tafel slope of 45 mV dec−1, in rotating disk measurements under saturated N2 conditions.
176 citations
TL;DR: The synthesis and complete characterization of a new purely organic sensitizer (RK1) that can be prepared and synthetically upscaled rapidly is reported that achieves one of the best output power conversion efficiencies for a solar cell based on the iodine/iodide electrolyte, combining high efficiency and outstanding stability.
Abstract: Among the new photovoltaic technologies, the Dye-Sensitized Solar Cell (DSC) is becoming a realistic approach towards energy markets such as BIPV (Building Integrated PhotoVoltaics). In order to improve the performances of DSCs and to increase their commercial attractiveness, cheap, colourful, stable and highly efficient ruthenium-free dyes must be developed. Here we report the synthesis and complete characterization of a new purely organic sensitizer (RK1) that can be prepared and synthetically upscaled rapidly. Solar cells containing this orange dye show a power conversion efficiency of 10.2% under standard conditions (AM 1.5G, 1000 Wm−2) using iodine/iodide as the electrolyte redox shuttle in the electrolyte, which is among the few examples of DSC using an organic dyes and iodine/iodide red/ox pair to overcome the 10% efficiency barrier. We demonstrate that the combination of this dye with an ionic liquid electrolyte allows the fabrication of solar cells that show power conversion efficiencies of up to 7.36% that are highly stable with no measurable degradation of initial performances after 2200 h of light soaking at 65°C under standard irradiation conditions. RK1 achieves one of the best output power conversion efficiencies for a solar cell based on the iodine/iodide electrolyte, combining high efficiency and outstanding stability.
169 citations
TL;DR: The experimental realization of stable counter-electrode (CE) electrocatalysts by alloying Pt with transition metals for enhanced dissolution resistance to state-of-the-art iodide/triiodide (I(-)/I3(-)) redox electrolyte is presented.
Abstract: The dissolution of platinum (Pt) has been one of the heart issues in developing advanced dye-sensitized solar cells (DSSCs). We present here the experimental realization of stable counter-electrode (CE) electrocatalysts by alloying Pt with transition metals for enhanced dissolution resistance to state-of-the-art iodide/triiodide (I(-)/I3(-)) redox electrolyte. Our focus is placed on the systematic studies of dissolution engineering for PtM0.05 (M=Ni, Co, Fe, Pd, Mo, Cu, Cr, and Au) alloy CE electrocatalysts along with mechanism analysis from thermodynamical aspects, yielding more negative Gibbs free energies for the dissolution reactions of transition metals. The competitive reactions between transition metals with iodide species (I3(-), I2) could protect the Pt atoms from being dissolved by redox electrolyte and therefore remain the high catalytic activity of the Pt electrode.
167 citations
TL;DR: In this article, several sulfidic chalcogels were explored as iodine sorbents including NiMoS4, CoMoS 4, Sb4Sn3S12, Zn2Sn2S6, and K0.16CoSx.
Abstract: Iodine (129I and 131I) is one of the radionuclides released in nuclear fuel reprocessing and poses a risk to public safety due to its involvement in human metabolic processes. In order to prevent the release of hazardous radioactive iodine into the environment, its effective capture and sequestration is pivotal. In the context of finding a suitable matrix for capturing radioactive iodine, several sulfidic chalcogels were explored as iodine sorbents including NiMoS4, CoMoS4, Sb4Sn3S12, Zn2Sn2S6, and K0.16CoSx (x = 4–5). All of the chalcogels showed high uptake, reaching up to 225 mass % (2.25 g/g) of the final mass owing to strong chemical and physical iodine–sulfide interactions. Analysis of the iodine-loaded specimens revealed that the iodine chemically reacted with Sb4Sn3S12, Zn2Sn2S6, and K0.16CoSx to form the metal complexes SbI3, SnI4, and, KI, respectively. The NiMoS4 and CoMoS4 chalcogels did not appear to undergo a chemical reaction with iodine since iodide complexes were not observed with these s...
TL;DR: An unprecedented reaction for the direct trifluoromethylthiolation and fluorination of alkyl alcohols using AgSCF3 and nBu4NI has been developed and is tolerant of different functional groups.
Abstract: An unprecedented reaction for the direct trifluoromethylthiolation and fluorination of alkyl alcohols using AgSCF3 and nBu4NI has been developed. The trifluoromethylthiolated compounds and alkyl fluorides were selectively formed by changing the ratio of AgSCF3/nBu4NI. This protocol is tolerant of different functional groups and might be applicable to late-stage trifluoromethylthiolation of alcohols.
TL;DR: A mechanism explaining the highly efficient removal of radioactive I(-) has been proposed according to characterization analyses of the composites after adsorption and subsequently been verified by adsor adaptation and desorption experiments.
TL;DR: In this paper, the thermodynamic stability and electronic properties of lead iodide perovskites with large guanidinium cations having a nearly zero dipole moment were investigated.
Abstract: Three-dimensional organic–inorganic lead iodide perovskites are potential photoconductive materials for solar cells. Nowadays, a high power conversion efficiency exceeding 20% can be achieved. However, perovskite solar cells are reported to suffer from a large hysteresis in the current–voltage curves. This may be attributed to the motion of organic cations with a permanent dipole moment in response to the applied electric field. Therefore, in order to suppress the hysteresis, organic cations that have a zero dipole moment and a molecular size well fitted to the lead iodide cavity are required. Using density functional theory calculations, we theoretically studied the thermodynamic stability and electronic properties of lead iodide perovskites with large guanidinium cations having a nearly zero dipole moment and compared the results with those predicted via the Goldschmidt tolerance factor. The properties of formamidinium–guanidinium (FA1–xGAxPbI3) intermediate alloys were also investigated.
TL;DR: A transition-metal-free coupling protocol between aryl alkyne and alkyl iodide enabled by photoenergy in water is presented and a tentative mechanism for the coupling is also proposed.
Abstract: Methods to assemble alkynes are essential for synthesizing fine chemicals, pharmaceuticals and polymeric photo-/electronic materials. Using light as a clean energy form and water as a green solvent has the potential to make synthetic chemistry more environmentally friendly. Here we present a transition-metal-free coupling protocol between aryl alkyne and alkyl iodide enabled by photoenergy in water. Under ultraviolet irradiation and in basic aqueous media, aryl alkynes efficiently couple with a wide range of alkyl iodides including primary, secondary and tertiary ones under mild conditions. A tentative mechanism for the coupling is also proposed.
TL;DR: It is shown that single-step blade-coating and immersion in a ligand exchange solution such as the one containing methylammonium iodide can be used to fabricate well performing bottom-gate/bottom-contact PbS CQD field effect transistors with record subthreshold swing.
Abstract: In the past years, halide capping became one of the most promising strategies to passivate the surface of colloidal quantum dots (CQDs) in thin films to be used for electronic and optoelectronic device fabrication. This is due to the convenient processing, strong n-type characteristics, and ambient stability of the devices. Here, we investigate the effect of three counterions (ammonium, methylammonium, and tetrabutylammonium) in iodide salts used for treating CQD thin films and shed light on the mechanism of the ligand exchange. We obtain two- and three-dimensional square-packed PbS CQD superlattices with epitaxial merging of nearest neighbor CQDs as a direct outcome of the ligand-exchange reaction and show that the order in the layer can be controlled by the nature of the counterion. Furthermore, we demonstrate that the acidity of the environment plays an important role in the substitution of the carboxylates by iodide ions at the surface of lead chalcogenide quantum dots. Tetrabutylammonium iodide shows lower reactivity compared to methylammonium and ammonium iodide due to the nonacidity of the cation, which eventually leads to higher order but also poorer carrier transport due to incomplete removal of the pristine ligands in the QD thin film. Finally, we show that single-step blade-coating and immersion in a ligand exchange solution such as the one containing methylammonium iodide can be used to fabricate well performing bottom-gate/bottom-contact PbS CQD field effect transistors with record subthreshold swing.
TL;DR: The corrosion inhibition properties of some organic dyes, namely Sunset Yellow (SS), Amaranth (AM), Allura Red (AR), Tartrazine (TZ) and Fast Green (FG), for mild steel corrosion in 0.5 M HCl solution were investigated using gravimetric, potentiodynamic polarization techniques and quantum chemical calculations.
Abstract: The corrosion inhibition properties of some organic dyes, namely Sunset Yellow (SS), Amaranth (AM), Allura Red (AR), Tartrazine (TZ) and Fast Green (FG), for mild steel corrosion in 0.5 M HCl solution, were investigated using gravimetric, potentiodynamic polarization techniques and quantum chemical calculations. The results showed that the studied dyes are good corrosion inhibitors with enhanced inhibition efficiencies. The inhibition efficiency of all the studied dyes increases with increase in concentration, and decreases with increase in temperature. The results showed that the inhibition efficiency of the dyes increases in the presence of KI due to synergistic interactions of the dye molecules with iodide (I−) ions. Potentiodynamic polarization results revealed that the studied dyes are mixed-type inhibitors both in the absence and presence of KI. The adsorption of the studied dyes on mild steel surface, with and without KI, obeys the Langmuir adsorption isotherm and involves physical adsorption mechanism. Quantum chemical calculations revealed that the most likely sites in the dye molecules for interactions with mild steel are the S, O, and N heteroatoms.
TL;DR: The mechanism may involve photoinduced electron reduction of C60-fullerene producing I· or I2 followed by subsequent intermolecular electron-transfer events of (C60>)-· to produce reactive radicals.
TL;DR: This reaction is the first example of introducing an acyl group at the ortho position of aryl iodides, and the proposed PdIV complex, generated via oxidative addition of the carboxylic anhydrides, is a key intermediate for this transformation.
Abstract: A new palladium-catalyzed three-component coupling involving acylation/alkenylation of aryl iodide is reported. The reaction was carried out with readily available starting materials and gave the ortho-acylated styrene in moderate to good yields. Compared with previous Catellani–Lautens reactions, this reaction is the first example of introducing an acyl group at the ortho position of aryl iodides. The proposed PdIV complex, generated via oxidative addition of the carboxylic anhydrides, is a key intermediate for this transformation.
TL;DR: In this article, the formal potential (E0′) of the I2 process and the stability constant (Kstab) of I3− in two protic solvents (water and ethanol), two aprotic ionic liquids (acetonitrile and propylene carbonate), and one PIL were calculated using the voltammetric methodology developed in this paper.
Abstract: The iodide/triiodide/iodine (I–/I3–/I2) redox system has been the subject of electrochemical investigations for well over half a century and remains a contemporary research interest due to the integral role of the I–/I3– couple in dye-sensitized solar cell (DSSC) technology. In this study, we have calculated the formal potential (E0′) of the I–/I2 process and the stability constant (Kstab) of I3– in two protic solvents (water and ethanol), two aprotic solvents (acetonitrile and propylene carbonate), eight aprotic ionic liquids (AILs), and one protic ionic liquid (PIL) using the voltammetric methodology developed herein. Furthermore, using 1-ethyl-3-methylimidazlium bis(trifluoromethanesulfonyl)imide (abbr. [C2mim][NTf2]) as a “model” ionic liquid-based DSSC electrolyte system, we have also investigated the influence of three common additives/impurities in DSSCs (i.e., tert-butylpyridine, Li+, and water) on the parameters E0′(I–/I2) and Kstab and characterized two analogous redox systems, Br–/Br3–/Br2 and ...
TL;DR: The aromatic perfluoroalkylation catalyzed by a copper(I) salt with bis(perfluoroalky)zinc reagents Zn(RF)2(DMPU)2, which were prepared and then isolated as a stable white powder from perfluoromethyl iodide and diethylzinc, was accomplished to provide the perfluoalkylated products in good-to-excellent yields.
Abstract: The aromatic perfluoroalkylation catalyzed by a copper(I) salt with bis(perfluoroalkyl)zinc reagents Zn(RF)2(DMPU)2, which were prepared and then isolated as a stable white powder from perfluoroalkyl iodide and diethylzinc, was accomplished to provide the perfluoroalkylated products in good-to-excellent yields. The advantages of this reliable and practical catalytic reaction are 1) air-stable and easy-to-handle bis(perfluoroalkyl)zinc reagents can be utilized, 2) the reagent is reactive and hence the operation without activators and ligands is simple, and 3) not only trifluoromethylation but also perfluoroalkylation can be attained.
TL;DR: Mixed iodide-bromide methylammonium lead perovskite diodes function as efficient solar cells with power conversion efficiencies as high as 12.9% when illuminated with AM1.5 simulated sunlight.
Abstract: Vacuum deposition techniques are used to prepare mixed iodide–bromide methylammonium lead perovskite diodes via an intermediate double layer of the pure iodide and bromide perovskites. The diodes lead to bright electroluminescence, whose emission spectra maxima shift from the infrared toward the visible with increasing bromide content. When illuminated with AM1.5 simulated sunlight the devices function as efficient solar cells with power conversion efficiencies as high as 12.9%.
TL;DR: Understanding the origins of the observed optoelectronic properties of these two compounds, with respect to their distinct topologies and organic-inorganic interactions, provides insight into the design of tropylium-containing compounds for potential optical and electronic applications.
Abstract: Inorganic materials with organic constituents—hybrid materials—have shown incredible promise as chemically tunable functional materials with interesting optical and electronic properties. Here, the preparation and structure are reported of two hybrid materials containing the optoelectronically active tropylium ion within tin- and lead-iodide inorganic frameworks with distinct topologies. The crystal structures of tropylium tin iodide, (C7H7)2SnI6, and tropylium lead iodide, C7H7PbI3, were solved using high-resolution synchrotron powder X-ray diffraction informed by X-ray pair distribution function data and high-resolution time-of-flight neutron diffraction. Tropylium tin iodide contains isolated tin(IV)-iodide octahedra and crystallizes as a deep black solid, while tropylium lead iodide presents one-dimensional chains of face-sharing lead(II)-iodide octahedra and crystallizes as a bright red-orange powder. Experimental diffuse reflectance spectra are in good agreement with density functional calculations ...
TL;DR: A Pt- and FTO-free counter electrode outperforming the best conventional combination is obtained, and Mo film is found to significantly decrease the sheet resistance of the counter electrode, contributing to the excellent device performance.
Abstract: Due to the two-dimensional confinement of electrons, single- and few-layer MoSe2 nanostructures exhibit unusual optical and electrical properties and have found wide applications in catalytic hydrogen evolution reaction, field effect transistor, electrochemical intercalation, and so on. Here we present a new application in dye-sensitized solar cell as catalyst for the reduction of I3− to I− at the counter electrode. The few-layer MoSe2 is fabricated by surface selenization of Mo-coated soda-lime glass. Our results show that the few-layer MoSe2 displays high catalytic efficiency for the regeneration of I− species, which in turn yields a photovoltaic energy conversion efficiency of 9.00%, while the identical photoanode coupling with “champion” electrode based on Pt nanoparticles on FTO glass generates efficiency only 8.68%. Thus, a Pt- and FTO-free counter electrode outperforming the best conventional combination is obtained. In this electrode, Mo film is found to significantly decrease the sheet resistance of the counter electrode, contributing to the excellent device performance. Since all of the elements in the electrode are of high abundance ratios, this type of electrode is promising for the fabrication of large area devices at low materials cost.
TL;DR: In this paper, a combined X-ray and UV photoemission spectroscopy study (XPS and UPS) of organic-inorganic perovskites prepared from a solution of lead chloride (PbCl2) and methylammonium iodide (CH3NH3I) was conducted.
Abstract: We report on a combined X-ray and UV photoemission spectroscopy study (XPS and UPS) of organic–inorganic perovskites prepared from a solution of lead chloride (PbCl2) and methylammonium iodide (CH3NH3I). The XPS intensities are consistent with a pure iodide perovskite (CH3NH3PbI3), with no detectable chloride left. However, we found that the elimination of chloride results in residual methylamine molecules (CH3NH2) trapped within the perovskite crystal lattice. Furthermore, we show that vacuum annealing or sputtering induces the formation of a thin PbI2 layer at the crystal surface which acts as a surface barrier blocking electron transfer from the underlying perovskite film.
TL;DR: An organic-ligand-free cuprous iodide trinuclear cluster with significant temperature-dependent structural distortion has been synthesized and characterized, which shows thermochromic luminescence originating from a single cluster-centered triplet due to the absence of an organic ligand.
TL;DR: The reactivity of PAA with halide ions to form secondary oxidants (HOCl, HOBr) was investigated and found that in PAA-treated solutions with [H2O2] > [PAA], the HOBr steady-state concentrations were low with a limited formation of brominated (chlorinated) disinfection byproducts (DBPs).
Abstract: Peracetic acid (PAA) is a disinfectant considered for use in ballast water treatment, but its chemical behavior in such systems (i.e., saline waters) is largely unknown. In this study, the reactivity of PAA with halide ions (chloride and bromide) to form secondary oxidants (HOCl, HOBr) was investigated. For the PAA-chloride and PAA-bromide reactions, second-order rate constants of (1.47 ± 0.58) × 10(-5) and 0.24 ± 0.02 M(-1) s(-1) were determined for the formation of HOCl or HOBr, respectively. Hydrogen peroxide (H2O2), which is always present in PAA solutions, reduced HOCl or HOBr to chloride or bromide, respectively. As a consequence, in PAA-treated solutions with [H2O2] > [PAA], the HOBr (HOCl) steady-state concentrations were low with a limited formation of brominated (chlorinated) disinfection byproducts (DBPs). HOI (formed from the PAA-iodide reaction) affected this process because it can react with H2O2 back to iodide. H2O2 is thus consumed in a catalytic cycle and leads to less efficient HOBr scavenging at even low iodide concentrations (<1 μM). In PAA-treated solutions with [H2O2] < [PAA] and high bromide levels, mostly brominated DBPs are formed. In synthetic water, bromate was formed from the oxidation of bromide. In natural brackish waters, bromoform (CHBr3), bromoacetic acid (MBAA), dibromoacetic acid (DBAA), and tribromoacetic acid (TBAA) formed at up to 260, 106, 230, and 89 μg/L, respectively for doses of 2 mM (ca. 150 mg/L) PAA and [H2O2] < [PAA]. The same brackish waters, treated with PAA with [H2O2] ≫ [PAA], similar to conditions found in commercial PAA solutions, resulted in no trihalomethanes and only low haloacetic acid concentrations.
TL;DR: In this article, a water-stable MOF, MIL-101(Cr)-SO3H, via ion exchange process, was successfully loaded with silver(I) via ion transfer process.
TL;DR: In this article, experimental studies concerning the absorption spectra of molecular iodine and its I−, anions in the spectral band of 180-600 nm have been conducted, and relations of absorption coefficients to concentrations have been studied.
Abstract: The paper reports on experimental studies concerning the absorption spectra of molecular iodine and its , I−, anions in the spectral band of 180–600 nm. Values of the absorption cross-sections of the above mentioned substances have been measured, and relations of absorption coefficients to concentrations have been studied. The results obtained demonstrate that the spectral band under consideration is likely to be successfully used for simultaneous real-time detection of substances containing iodine with an absorption method using laser emission sources in the UV and visible light spectral bands.