Ammonium Iodide Research Articles

Synthesis of Perovskite Film by Using Lead Nitrate as Precursor for Perovskite Solar Cell Applications

Abstract Perovskite film is normally synthesized from lead iodide (PbI2) and methyl ammonium iodide (MAI, CH3NH3I) to form CH3NH3PbI3 perovskite film in p-i-n perovskite solar cell. However, PbI2 is difficultly dissolved for fabrication process. Lead nitrate (Pb(NO3)2) is considered as one alternative material that can be used to synthesize perovskite film with some advantages such as low cost material, non-toxic solvent requirement and water dissolvable. Thus, this study aims to synthesize perovskite film by using Pb(NO3)2 and MAI as stating materials. Spin coating method was used to deposit perovskite precursor for p-i-n perovskite solar cell fabrication. The crystal structure, surface morphology and optical property of perovskite film were investigated by X-ray diffraction, scanning electron microscope and UV-visible spectroscopy, respectively. For solar cell applications, the perovskite solar cell fabricated with Pb(NO3)2 showed lower performance than with PbI2. The low performance was resulted from the incomplete formation of perovskite film due to effects of pinhole and non-smooth film surface. However, this work demonstrated that Pb(NO3)2 has possibility to use as starting material for perovskite solar cell fabrication with non-toxic solvent process. To improve solar cell performance, perovskite film synthesized from Pb(NO3)2 should be further investigated.

Visible-Light-Promoted Se-Arylation of Diaryl Diselenides with 2-Phenylimidazopyridines in the Presence of Ammonium Iodide: Synthesis of 2-Phenyl-3-(arylselanyl)imidazo[1,2-α]pyridines

Visible-Light-Promoted Se-Arylation of Diaryl Diselenides with 2-Phenylimidazopyridines in the Presence of Ammonium Iodide: Synthesis of 2-Phenyl-3-(arylselanyl)imidazo[1,2-α]pyridines

A strategy for improving the performance of perovskite red light-emitting diodes by controlling the growth of perovskite crystal

Small Cs0.8FA0.2PbI3 perovskite crystal grains with α-phase structure were prepared by a one-step spin-coating method using both polyethylene oxide (PEO) and 1-naphthylmethyl ammonium iodide (NMAI).

Physicochemical and Biopharmaceutical Characterization of N-Iodomethyl-N,N-Dimethyl-N-(6,6-1 Diphenylhex-5-En-1-Yl) Ammonium Iodide and A Promising Antileishmania Delivery System

Physicochemical and Biopharmaceutical Characterization of N-Iodomethyl-N,N-Dimethyl-N-(6,6-1 Diphenylhex-5-En-1-Yl) Ammonium Iodide and A Promising Antileishmania Delivery System

In(III) and Hf(IV) Triflate-Catalyzed Hydration and Catalyst-free Hydrohalogenation of Aryl Acetylenes in Liquid Sulfur Dioxide.

The use of liquid sulfur dioxide as a reaction solvent to promote chemical transformations of alkynes has been explored. First, a combination of liquid SO2 and In(OTf)3 or Hf(OTf)4 as a catalyst allows to perform hydration of aryl alkynes under mild conditions without a direct addition of Brønsted acid. Second, novel catalyst-free conditions for the synthesis of α-vinyl iodides, bromides, and chlorides from aryl alkynes have been developed in liquid SO2 using group I and II metal halides and ammonium iodide as the halide ion sources.

Physicochemical and Ion-Sensing Properties of Benzofurazan-Appended Calix[4]arene in Solution and on Gold Nanoparticles: Spectroscopy, Microscopy, and DFT Computations in Support of the Species of Recognition.

A calix[4]arene conjugate (L) functionalized at the lower rim with a benzofurazan fluorophore (NBD) and at the upper rim with a thioether moiety has been synthesized and characterized by 1H NMR, 13C NMR, and mass spectrometry techniques. Both the absorption and emission spectral data for L in different solvents exhibited progressive changes with an increase in polarity. Ion recognition studies were performed by absorption and fluorescence spectroscopy using 10 different metal ions. Among these, Hg2+ exhibited greater changes in these spectra, whereas Cu2+ showed only significant changes and all other ions showed no change in the spectral features. Although the Hg2+ has dominant influence on the spectral features and provides a detection limit of 56.0 ± 0.6 ppb, the selectivity was hampered because of the presence of the derivatizations present on both the rims of L for ion interaction in solution. Therefore, L was immobilized onto gold nanoparticles (AuNPL’s) so that the upper rim derivatizations anchor onto the gold surface through Au–S interactions, and this leaves out only the lower rim NBD derivatization for interaction with ions selectively. The AuNPL’s were characterized by transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy (XPS) analyses. The surface characteristics were analyzed by contact angle measurements. The AuNPL’s exhibit greater selectivity and enhanced sensitivity for Hg2+ ions with a lowest detection limit of 48.0 ± 0.8 ppb. The immobilization of L onto AuNPs was reflected in the corresponding fluorescence lifetime values, and the addition of Hg2+ to either L or AuNPL showed fluorescence quenching. The reversible recognition of Hg2+ by L was demonstrated by titrating L or AuNPL with Hg2+ followed by tetra-butyl ammonium iodide for several cycles. The structural features of Hg2+-bound species were demonstrated by density functional theory computations and were supported by the XPS data. The Hg2+ induces aggregated fibrillar morphology into supramolecular L, as demonstrated by microscopy when Hg2+ was added either to L or to AuNPL, supporting aggregation-caused quenching.

Development of Next‐Generation Organic‐Based Solar Cells: Studies on Dye‐Sensitized and Perovskite Solar Cells

AbstractNext‐generation organic solar cells such as dye‐sensitized solar cells (DSSCs) and perovskite solar cells (PSCs) are studied at the National Institute of Advanced Industrial Science and Technology (AIST), and their materials, electronic properties, and fabrication processes are investigated. To enhance the performance of DSSCs, the basic structure of an electron donor, π‐electron linker, and electron acceptor, i.e., D–π–A, is suggested. In addition, special organic dyes containing coumarin, carbazole, and triphenylamine electron donor groups are synthesized to find an effective dye structure that avoids charge recombination at electrode surfaces. Meanwhile, PSCs are manufactured using both a coating method and a laser deposition technique. The results of interfacial studies demonstrate that the level of the conduction band edge (CBE) of a compact TiO2 layer is shifted after TiCl4 treatment, which strongly affects the solar cell performance. Furthermore, a special laser deposition system is developed for the fabrication of the perovskite layers of PSCs, which facilitates the control over the deposition rate of methyl ammonium iodide used as their precursor.

Ion specificity towards structure-property correlation of poly (ethylene oxide) [PEO]-NH4I and PEO-KBr composite solid polymer electrolyte

Ion conduction mechanism in polymer-salt composite is highly dependent on the optimization of the process parameters. In this investigation, studies on poly (ethylene oxide) [PEO] with different salt viz. ammonium Iodide (NH4I) and potassium bromide (KBr) [represented as N-series and K-series respectively] are carried out. Highest ionic conductivity of ~ 10−4 S cm−1 is observed for PEO-NH4I (20%) composite which is found to be the most amorphous. FTIR spectra of N-series are deconvoluted within 3187–3442 cm−1 in order to estimate the percentage of free and contact ions. Number density of free ions is found to increase proportionately with the salt content. Detailed characterization is carried out in view of salt-induced microstructural inhomogeneity. Flexibility of the polymer blend is reflected in several ion-transport parameters like carrier concentration, mobility, etc. Two relaxation times [τ1 (~ 10−4 s) and τ2 (~ 10−7 s)] as being exhibited in the complex electric modulus clearly illustrate the existence of both amorphous and crystalline regimes within PEO-salt composite.

Investigation of Antimicrobial Properties of QASs+ (Novel Synthesis)

Quaternary ammonium salts (QASs) are bioactive materials known for their antimicrobial effects. However, it is difficult to provide desirable quaternary ammonium salts. Thus, firstly new quarternary ammonium salts which are not in the literature were synthesized and organoclays were prepared with different quarternary ammonium salts content. The organoclays included quaternary ammonium salts such as N,N-di (3-methyl butyl)-N-(1-phenylethyl)-N-methyl ammonium Iodide (QAS-1), N,N-dipentil-N-(1-phenylethyl)-N-methyl ammonium Iodide (QAS-2), and N,N-dihexcyl-N-(1-phenylethyl)-N-methyl ammonium Iodide (QAS-3) which were newly synthesized for modification of Na+-montmorillonite (Na+-Mt) and were characterized by nuclear magnetic resonance spectroscopy (NMR). Synthesized organoclays were characterized by using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Characterization results proved that the modification is performed with high performance and as seen in the XRD results, the interstratum distances increased considerably and the diffraction angles decreased. The antimicrobial activity of the organoclays against Staphylococcus aureus and Escherichia coli were studied in detail and were obtained much larger inhibition zones than similar studies. QAS-3-Mt organoclay showed the maximum of antimicrobial activity against S. aureus and E. coli. As is known, organoclay comes among the fillers that play the most effective role in the synthesis of composite materials. In this context, the product we have synthesized is unique and can be used for many purposes.

Synthesis and Characterization of Methylammonium Lead Iodide Perovskite and its Application in Planar Hetero-junction Devices

The present paper reports on the synthesis and characterization of methylammonium lead iodide perovskite thin film and its applications in heterojunction devices. Perovskite thin films were deposited by a simple spin-coating method using a precursor solution including methyl ammonium iodide and lead iodide onto a glass substrate. The surface morphology study via field emission scanning electron microscopy of the perovskite thin film shows complete surface coverage on glass substrate with negligible pin-holes. UV–visible spectroscopy study revealed a broad absorption range and the exhibition of a band-gap of 1.6 eV. The dark current-voltage (I–V) characteristics of all the devices under study show rectifying behaviour similar to the Schottky diode. Various device parameters such as ideality factor and barrier height are extracted from the I–V curve. At low voltages the devices exhibit Ohmic behaviour, trap free space charge limited conduction governs the charge transport at an intermediate voltage range, while at much higher voltages the devices show trap controlled space charge limited conduction. Furthermore, impedance spectroscopy measurements enable us to extract the various internal parameters of the devices. Correlations between these parameters and I–V characteristics are discussed. The different capacitive process arising in the devices was discussed using the capacitance versus frequency curve.

Towards an Asymmetric Organocatalytic α-Azidation of β-Ketoesters

Detailed investigations concerning the organocatalytic (asymmetric) α-azidation of prochiral β-ketoesters were carried out. It was shown that the racemic version of such a reaction can either be carried out under oxidative conditions using TMSN3 as the azide-source with quaternary ammonium iodides as the catalysts, or by using hypervalent iodine-based electrophilic azide-transfer reagents with different organocatalysts. In addition, the latter strategy could also be carried out with modest enantioselectivities when using simple cinchona alkaloid catalysts, albeit with relatively low yields.

Strontium-mediated selective protonation of unsaturated linkage of aromatic hydrocarbons and these derivatives

The selective protonation of aromatic hydrocarbons with at least two or more aromatic rings and aromatic compounds bearing unsaturated linkages can be achieved by metallic strontium metal with ammonium chloride and iodine, or ammonium iodide in tetrahydrofuran. The reaction system is ammonia-free in room temperature and the reaction proceeds high selectivity in moderate to good yields.

Mixed 3D–2D Passivation Treatment for Mixed‐Cation Lead Mixed‐Halide Perovskite Solar Cells for Higher Efficiency and Better Stability

AbstractLayered low‐dimensional perovskite structures employing bulky organic ammonium cations have shown significant improvement on stability but poorer performance generally compared to their 3D counterparts. Here, a mixed passivation (MP) treatment is reported that uses a mixture of bulky organic ammonium iodide (iso‐butylammonium iodide, iBAI) and formammidinium iodide (FAI), enhancing both power conversion efficiency and stability. Through a combination of inactivation of the interfacial trap sites, characterized by photoluminescence measurement, and formation of an interfacial energetic barrier by which ionic transport is reduced, demonstrated by Kelvin probe force microscopy, MP treatment of the perovskite/hole transport layer interface significantly suppresses photocurrent hysteresis. Using this MP treatment, the champion mixed‐halide perovskite cell achieves a reverse scan and stabilized power conversion efficiency of 21.7%. Without encapsulation, the devices show excellent moisture stability, sustaining over 87% of the original performance after 38 d storage in ambient environment under 75 ± 20% relative humidity. This work shows that FAI/iBAI, is a new and promising material combination for passivating perovskite/selective‐contact interfaces.

Sorption and desorption of anionic, cationic and zwitterionic polyfluoroalkyl substances by soil organic matter and pyrogenic carbonaceous materials

The fraction of pyrogenic carbonaceous materials (PCMs) left in aqueous film-forming foams (AFFFs) source zones may strongly affect the persistence of perfluoroalkyl and polyfluoroalkyl substances (PFASs). To examine the hypothesis and gain an additional perspective on the potential contributions of different organic phases present in soil, we measured sorption and desorption of five AFFF relevant PFASs, one cationic (perfluoroctaneamido ammonium iodide, PFOAAmS), two anionic (perfluorooctane sulfonate, PFOS; perfluorooctanoic carboxylate, PFOA), and two zwitterionic (perfluorooctane amido betaine, PFOAB; 6:2 fluorotelomer sulfonamido betaine, 6:2 FTAB), by three types of PCMs (biochar, soot, and oil-free soot) and soil organic matter (SOM, presented by Pahokee peat) by single-solute batch sorption experiments. It was found that sorption to PCMs is substantially stronger and nonlinear than SOM, especially for the cationic PFOAAmS. Strong sorption to PCMs discovered in this study suggests that such phenomenon can lead to high retardation of PFASs in the AFFF source zone and decreased mobility of PFASs in groundwater, especially for the precursor compounds to the legacy perfluoroalkyl acids. Fouling of PCMs by unburnt oil would hinder the surface activity of PCMs and consequently lower the sorption of PFAS, thereby facilitating PFAS mobility. Moreover, sorption hysteresis was observed in all the systems with sorption of 6:2 FTAB by biochar being the most significant. This study for the first time provided the evidence that PCMs are potentially a significant sink of PFASs in AFFF-impacted sites.

Effect of carbon nanotubes as dispersoid in polymer electrolyte matrix

The present work deals with the characterization of a thin film polymer electrolyte based on poly(N-vinyl pyrrolidone) (PVP) doped with ammonium iodide (NH4I) and carbon nanotubes (CNT) as dispersoid to develop nanocomposite polymer electrolyte films using solution cast method. Carbon nanotubes were incorporated in PVP:NH4I matrix in different concentration. Electrochemical impedance spectroscopy technique was used for characterizing the polymer electrolyte system. 0.4 wt% MCNT containing system shows maximum conductivity (8.23 × 10−2 S/cm). The temperature dependent conductivity studies reveal the Arrhenius behavior. Differential scanning calorimetry analysis shows the decrease in the glass transition temperature (Tg) from 345 (60:40 PVP:NH4I) to 339 K (60:40 + 0.4 wt% PVP:NH4I + CNT). Dielectric phenomenon, concentration of charge carrier density (N) and dissociation factor also supports the conductivity data while ionic transference number (tion) studies confirms the ionic conductive nature of the electrolyte system.

Investigation of ionic conduction in PEO–PVDF based blend polymer electrolytes

We investigate the effect of blend host polymer on solid polymer electrolyte (SPE) films doped with ammonium iodide (NH4I) salt using a variety of experimental techniques. Structural studies on the composite SPEs show that the blending of Poly(ethylene oxide) (PEO)–Poly(vinylidene fluoride) (PVDF) polymers in a suitable ratio enhances the amorphous fraction of the polymer matrix and facilitates fast ion conduction through it. We observe that the addition of a small amount of PVDF in the PEO host polymer enhances the ion – polymer interaction leading to more ion dissociation. As a result, the effective number of mobile charge carriers within the polymer matrix increases. Systematic investigation in these blend SPEs shows that the maximum conductivity (1.01 × 10–3 S/cm) is obtained for PEO – rich (80 wt. % PEO, 20 wt. % PVDF) composites at 35 wt. % NH4I concentration at room temperature. Interestingly, at higher salt concentrations (above 35 wt. %), the conductivity is found to decrease in this system. The reduction of conductivity at higher salt concentrations is the consequence of decrease in the carrier concentration due to the formation of an ion pair and ion aggregates. PVDF–rich compositions (20 wt. % PEO and 80 wt. % PVDF), on the other hand, show a very complex porous microstructure. We also observe a much lower ionic conductivity (maximum ∼ 10–6 S/cm at 15 wt. % salt) in these composite systems relative to PEO-rich composites.

Edge-functionalized graphene quantum dots as a thickness-insensitive cathode interlayer for polymer solar cells

A thickness-insensitive cathode interlayer (CIL) is necessary for large-area polymer solar cells (PSCs), in which thickness variation is unavoidable. These CIL materials are typically based on n-type conjugated polymer/molecule backbones, which show strong light absorption in the visible/near-infrared (NIR) region. This interferes with the sunlight absorption by the active layer and deteriorates device efficiency. In this study, we developed graphene quantum dots functionalized with ammonium iodide (GQD-NI) at the edge as a thickness-insensitive CIL with high optical transparency. The peripheral ammonium iodide groups of GQD-NI formed the desired interfacial dipole with the cathode to decrease the work function. The graphene basal planes of GQD-NI with a lateral size of ca. 3 nm demonstrated a good conductivity of 3.56 × 10–6 S·cm–1 and high transparency in the visible/NIR region (λmaxabs = 228 nm). Moreover, GQD-NI was readily soluble in polar organic solvents, e.g., methanol, which enabled multilayer device fabrication with orthogonal solvent processing. As a result, the PSC device with GQD-NI as the CIL exhibited a power conversion efficiency (PCE) of 7.49%, which was much higher than that of the device without the CIL (PCE = 5.38%) or with calcium as the CIL (PCE = 6.72%). Moreover, the PSC device performance of GQD-NI was insensitive to the GQD-NI layer thickness in the range of 2–22 nm. These results indicate that GQD-NI is a very promising material for application as a CIL in large-area printed PSCs.

Electrochemical synthesis of thin, dense, and conformal anion exchange membranes with quaternary ammonium groups

We report for the first time the electrochemical synthesis in anodic and cathodic conditions of anion-conducting ionomer separators using two different precursors: N-(p-vinylbenzyl) N,N,N-trimethylammonium chloride (VBTMA) and (N-allyl N-benzyl N,N-dimethyl)ammonium iodide (ABDMA). The ionomer structure and microstructure are investigated by NMR and FTIR spectroscopies and Scanning Electron Microscopy. The quaternary ammonium groups are grafted in side chains (VBTMA) or are near the main chain (ABDMA). The anion conductivity is in the order of 1 mS/cm with quaternary ammonium groups in side chains and lower when the ammonium groups are near the main chain, where they probably reduce the anion mobility by steric hindrance. Such thin-film anion exchange membranes are a valuable asset for the realization of microfuel cells and solid-state water electrolysers.

Performance enhancement of perovskite solar cells using NH4I additive in a solution processing method

A two-step sequential deposition has been widely adopted to fabricate a perovskite film of planar heterojunction organo-lead halide perovskite solar cells. However, in this method complete conversion of Lead iodide (PbI2) into CH3NH3PbI3 is limited by the diffusion of CH3NH3I into PbI2 film, thus limits current density. Here, we report a facile method for enhancing perovskite film morphology by introducing a small amount of ammonium iodide (NH4I) as a halogen additive into PbI2 solution, which can react with PbI2 and forms nanostructured platelet structure that helps to diffusion of CH3NH3I, for further improving CH3NH3PbI3 film morphology. Under the optimized NH4I additive concentration of 5 wt%, the best power conversion efficiency (PCE) is 17.4% achieved, which is an improvement of 14% compared to that of the original device without the additive. SEM studies reveal that addition of NH4I into PbI2 films improves the porosity of the films, which helps to improve the perovskite film morphology by increasing the grain size. The enhancement of CH3NH3PbI3 film morphology is useful for increasing the optical absorption of perovskite film thereby increasing short-circuit current density, whence an improvement in the efficiency of the perovskite solar cell devices. The perovskite solar cells fabricated by this method preserved high crystallinity, negligible hysteresis, reliable reproducibility and improved stability.

A Facile Protocol for the Synthesis of Azoarenes from Nitroarenes using ammonium Iodide and Magnesium

A facile, efficient and cost-effective protocol for the synthesis of symmetrically substituted azoarenes from nitroarenes by using readily available ammonium iodide as hydrogen donor and magnesium powder as catalyst at room temperature in methanol media is described. The conversion of using this system is clean, rapid, chemoselective and high yielding. The azoarenes containing some additional substituents such as halogen, methyl, hydroxy, methoxy, ethoxy, etc. functions have been achieved in a single step by use of this reagent.