Ammonium Iodide Research Articles

Ion transport properties and performance of gellan gum based composite polymer membrane electrolytes in proton battery and PEMFC applications

Biopolymer Gellan gum (GG) incorporated with ammonium iodide (NH₄I) salts and inorganic filler nano-TiO2 improved the ion transport facility in the salt-polymer matrix. The crystalline/amorphous nature of the membranes and the presence of n-TiO2 are evident from XRD analysis. The vibration modes corresponding to the characteristic functional groups and bonding interactions within the polymer matrix and incorporated filler materials present in the as-prepared membranes were analyzed using FTIR technique respectively. The ion transport parameters such as ionic conductivity (σ), diffusion coefficient (D), and mobility (μ), were studied using Ac impedance, transference number measurement, and FTIR deconvolution. The biopolymer membrane with the composition, 1 g GG: 0.3 M.wt% of NH4I (GGAI-3) shows the highest ionic conductivity of 2.65 ± 0.03×10−3 S/cm and on addition of 0.1 M.wt% of n-TiO2 (GGAIT-1) the increase in ionic conductivity of 4.07 ± 0.02×10−2 S/cm was observed. The H¹NMR studies help in understanding the mobility of charge carriers upon their chemical shifts. The glass transition temperature values of the as-prepared membranes were determined using DSC studies. The morphological change on the surface of the GG polymer membrane due to the addition of NH4I and n-TiO2 were analyzed using the SEM technique. The thermal, mechanical, and chemical stability of the highest ion-conducting biopolymer and composite polymer membranes were assessed using TGA, mechanical stability tests, and chemical stability tests. The IEC test exhibits the number of exchangeable ions in the polymer matrix. Utilizing the GGAI-3 and GGAIT-1 membranes as electrolytes, proton batteries were constructed and observed to have the pseudocapacitive behaviour; as the electrodes experience surface limited redox reaction at the electrode-electrolyte interface. The PEMFC cell using the GGAI- 3 and GGAIT-1 as proton exchange membrane exhibits the OCV of 646 mV and 682 mV respectively. Their performances were analyzed using the I-V polarization curve resulted with the power density of 0.14 mW/cm2and 0.34 mW/cm2 respectively.

Syntheses of Diarylmethanes Via an Oxidative Benzylic Functionalization of P-Alkyl Phenol Derivatives Under Quaternary Ammonium Hypoiodite Catalysis.

We herein report two strategies for the quaternary ammonium hypoiodite-mediated oxidative benzylic functionalization of p-alkyl phenol derivatives. By using either dibenzoylperoxide or H2O2 in hexafluoroisopropanol in the presence of tetrabutyl ammonium iodide gives access to activated intermediates which can then be coupled with electron-rich aromatic compounds. Overall, this sequential two-step one-pot procedure gives access to diversely decorated diarylmethane derivatives straightforwardly. Furthermore, the suitability of these products to undergo further oxidation reactions was successfully demonstrated.

Polyvinylidene fluoride‐co‐hexafluoropropylene polymer gel electrolyte‐enabled dye‐sensitized solar cell for sustainable energy

AbstractDeveloped specifically to address leakage and stability concerns inherent in liquid electrolytes, this study presents a significant advancement in polymer gel electrolyte (PGE) formulation by combining potassium iodide (KI), ammonium iodide (AI) salts, and polyvinylidene fluoride‐co‐hexafluoropropylene (PVDF‐co‐HFP) as a host polymer. The tape casting method was employed to deposit the standard TiO2 paste as the photoanode and platinum paste as the counter electrode. N3 dye was incorporated, and PVDF‐co‐HFP was used as the PGE between the electrodes. The conductivity of PGE was measured by using a digitized conductivity meter. The quasi solid‐state solar cell (QS‐DSSC) assembled using single salts (KI, and AI), and mixed cations PGE was examined via photocurrent–voltage characteristics, and electrochemical impedance spectroscopy. The augmented ionic conductivity directly influences the efficiency of DSSCs. Notably, incorporating a mixed salt (KI + AI) within the PGE enhances ionic conductivity compared to single‐salt‐based counterparts. The resultant DSSCs using mixed salt PGE exhibit a Voc of 600 mV, Jsc of 1.01 mA/cm2, FF of 0.6089, and an efficiency of 0.369%, outperforming those using KI or AI. This highlights the perceptible advantages of employing this innovative electrolyte composition to enhance solar cell performance.

Large- and Small-Scale Syntheses of Donor-Free Rare-Earth Triiodides from the Metals and Ammonium Iodide.

Rare-earth triiodides free of donor solvents, LnI3 (Ln = Sc, Y, La-Lu), have been prepared in quantities as high as 76 g and in yields between 72% (Sc) and 98% (La) by the reaction between the corresponding metal and excess ammonium iodide in a two-step, one-pot procedure that is conducted in borosilicate glassware at temperatures of 350-430 °C in commercial tube furnaces. Procedures for both large-scale and small-scale syntheses are described, with specific examples for Ln = Sc, Y, La, Pr, Nd, Gd, Dy, Ho, and Lu. While the large-scale synthesis described here utilizes specialized glassware, the small-scale preparation may be performed in commercially available glassware.

Cu(II)/Base Synergistic Promoted [2 + 1 + 3] Cyclization of Cyclic Ketones with α,β-Unsaturated Aldehydes/Ketones and NH4I to Access Fused Pyridines.

Herein, a practical three-component [2 + 1 + 3] cyclization of various cyclic ketones with α,β-unsaturated aldehydes/ketones and ammonium iodide (NH4I) to access highly functional fused pyridines has been developed. The features of this transformation include mild reaction conditions, readily available starting materials, and excellent chemoselectivity. This protocol is compatible with various functional groups, and the preliminary studies on the mechanism of the reaction are also provided.

Surface Engineering Enables Efficient AgBiS2 Quantum Dot Solar Cells.

Surface ligand chemistry is vital to control the synthesis, diminish surface defects, and improve the electronic coupling of quantum dots (QDs) toward emerging applications in optoelectronic devices. Here, we successfully develop highly homogeneous and dispersed AgBiS2 QDs, focus on the control of interdot spacing, and substitute the long-chain ligands with ammonium iodide in solution. This results in improved electronic coupling of AgBiS2 QDs with excellent surface passivation, which greatly facilitates carrier transport within the QD films. Based on the stable AgBiS2 QD dispersion with the optimal ligand state, a homogeneous and densely packed QD film is prepared by a facile one-step coating process, delivering a champion power conversion efficiency of approximately 8% in the QD solar cells with outstanding shelf life stability. The proposed surface engineering strategy holds the potential to become a universal preprocessing step in the realm of high-performance QD optoelectronic devices.

Carbazole Treated Waterproof Perovskite Films with Improved Solar Cell Performance

AbstractSurface passivation has been widely employed to suppress non‐radiative charge recombination and prevent interfacial charge accumulation in perovskite photovoltaics. In this report, carbazole modified with ammonium iodide connected via alkyl chains of different lengths (i.e., ethyl, butyl, and hexyl chains) is used to form passivation layers on formamidinium lead triiodide FAPbI3‐based perovskite films to improve operational stability. Owing to the strong hydrophobicity of the carbazole moiety, it is observed that the perovskite films with a carbazole passivation layer retain their initial properties even after direct contact with a water droplet for 100 s. In addition, carbazole treatment reduces the rate of trap‐assisted recombination at the surface and grain boundaries of the perovskite layer. Furthermore, it accelerates interfacial hole transfer from the perovskite to the charge transport layer. As a result, devices treated with carbazole hexylammonium iodide achieve a power conversion efficiency (PCE) of up to 24.3% during quasi‐steady‐state (QSS) measurements with extraordinary long‐term operational stability under conditions of the ISOS‐L‐1 protocol, maintaining 95% of their initial efficiency after 1000 h.

Peptide‐Based Ammonium Halide with Inhibited Deprotonation Enabling Effective Interfacial Engineering for Highly Efficient and Stable FAPbI3 Perovskite Solar Cells

AbstractAmmonium iodides are intensively investigated as effective interfacial passivation agents in perovskite solar cells (PSCs) while facing a major challenge of their high reactivity with perovskites that undermines the operational stability of the PSCs. Exemplified by involving rationally designed/selected peptide into the widely adopted phenethylammonium iodide (PEAI), the present work demonstrates that the bespoke peptide‐PEAI can effectively inhibit the deprotonation of ammonium iodides and thus hinder the formation of 2D perovskite, facilitating the stability enhancement in perovskite films by multi hydrogen bonding. The additional lone pair electrons provided by peptide molecules can also enhance the passivation ability of the modified layer. Attributed to the stable co‐modifier peptide‐PEAI, the small‐area FAPbI3‐based PSCs yield a high efficiency of 25.02% with robust light and thermal stabilities. Moreover, the peptide‐PEAI‐based minimodules with an efficiency of 19.06% for a total area of 36 cm2 manifested the great application potential of this co‐modification strategy in the perovskite photovoltaics.

Dual interfacial modification with 1D perovskite for self-assembled monolayer based inverted perovskite solar cells

Recently, self-assembled monolayer (SAM) based inverted perovskite solar cells (PSCs) have been extensively studied due to their remarkable stability and compatibility with large-area devices. Microporesat the SAM/perovskite buried interface are commonly observed, which result in the increased defect density and hindered charge extraction. Herein, a multifunctional organic material, namely 2-(methylthio)-4,5-dihydro-1 H-imidazole ammonium iodide (MTIm), is introduced as an interfacial modification material to react with the residual PbI2, forming one-dimensional (1D) (MTIm)PbI3 small grains. We found that the 1D perovskite distributes at both top and buried interfaces of PSC, achieving dual-interfacial passivation of defects. Moreover, the 1D perovskite leads to a favorable n-type doping at the top interface, and relaxes the lattice strain at the buried interface. As a result, the champion PSC device achieves significantly improved power conversion efficiency from 21.7 % to 23.8 %, and retains over 90 % of its initial PCE after storing in air for 1500 hours.

A comparative study of alkylammonium halide interface modification for high efficiency and ion migration stability perovskite solar cells

Constructing 2D/3D perovskite heterostructures with organic molecules is key to improving the power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). However, a comprehensive understanding of the inhibitory relationship between the 2D perovskite layer and ion migration at the interface is still lacking. In this study, we use different alkyl ammonium iodides to build 2D/3D perovskite heterostructures. The research results show that both the chain length of alkyl and amino group count in alkyl ammonium iodide can significantly affect the crystal structure orientation of the 2D perovskite layer. A Dion-Jacobson (DJ) 2D/3D structure treated with ODADI shows superior defect passivation and carrier extraction, leading to PSCs with a 24.51 % PCE. Furthermore, the perovskite based on ODA cations eliminates the influence of Van der Waals interaction in perovskite based on BA or OA cations, which improves the stability of the lattice structure, and significantly inhibits ion migration. Therefore, after a maximum power point stability test of 1500 h, devices retain approximately 88 % of their initial PCE. This work offers fresh insights into optimizing interfaces in 2D/3D PSCs by selecting suitable organic molecules.

Multifunctional surface modification of carbon-based all-inorganic CsPbI2Br solar cells by 3-(trifluoromethyl) phenyltrimethyl ammonium iodide

The preparation process of carbon-electrode perovskite solar cells (C-PSCs) without hole transport layers (HTLs) is simple, cost-effective, and the as-prepared C-PSCs exhibit excellent thermal stability. However, there are numerous defects at the interfaces of C-PSCs and grain boundaries. Due to the presence of these defect states, non-radiative recombination of charge carriers occurs, ultimately resulting in significant VOC (voltage open circuit) loss and an energy level mismatch between device structures, which seriously affect the photoelectric conversion efficiency (PCE) and stability of C-PSCs. Therefore, this work uses 3-(trifluoromethyl)-phenyltrimethyl-ammonium iodide (TFPTAI) as a surface modifier to modify the surface of CsPbI2Br. Due to the strong electronegativity of fluorine atoms (F), acting as electron-withdrawing groups, they promote the separation of positive and negative charge centers in the molecule. This, in turn, can effectively induce strong binding of ammonium cations (NH+) with negatively charged defects, consequently suppressing the non-radiative recombination of charge carriers. In addition, thanks to the ordered arrangement of F atoms, a hydrophobic protective umbrella is constructed on the perovskite surface layer, effectively improving the stability of the device. The highest PCE of the as-prepared device is 14.02%, surpassing the optimal PCE of the original device at 12.46%. Simultaneously, the surface-modified device exhibits excellent environmental stability.

Ammonium iodide-incorporated SnO2 obtains perovskite solar cells with over 24% efficiency

Tin dioxide (SnO2) as the most promising electron transport layer (ETL) has been widely used in high-efficiency perovskite solar cells (PSCs) due to its excellent optical/electronic properties, chemical stability, and low-temperature processing. However, the surface of SnO2 ETL contains defect sites, which result in energy losses in PSCs. In order to passivate the defects of SnO2 surface and together tune the electronic properties of SnO2 ETL for getting high-performance PSCs, we herein incorporate the low-cost material ammonium iodide (NH4I) into the SnO2. After the NH4I doping, the optimized photovoltaic power conversation efficiency is significantly enhanced (the highest efficiency can reach 24.4%), the hysteresis of device is largely suppressed to a negligible level, and the stability of device is also obviously improved. The origin of these enhancements is further disclosed by the positive effects of NH4I doping on both ETL and perovskite film: the surface morphology of ETL is effectively flatten, the energy level of ETL is suitably adjusted, the electron mobility of ETL and the perovskite grain size are clearly increased, the surface defects of ETL and the trap states in the perovskite film are greatly reduced, and the PbI2 residue in the perovskite layer is obviously diminished. The study here of incorporating cheap inorganic small molecule in the ETL provides an ingenious way to enhance the performance of the planar PSCs.

Polyvinyl alcohol/ammonium iodide/ionic liquid‐4‐ethyl‐4‐methylmorpholiniumbromide based polymer electrolytes and its application in electric double layer capacitor

AbstractIn this study, we have synthesized solid polymer electrolytes using polyvinyl alcohol as a host polymer that has been doped with ionic liquid and ammonium iodide. Impedance spectroscopy revealed that the increase in ionic liquid doping increased the ionic conductivity of the PVA‐NH4I complex. The crystalline nature of the polymeric films was studied using polarized optical microscopy and x‐ray diffraction. To confirm the blending ability of polymer electrolyte, Fourier transform infrared spectroscopy was also used. Finally, a supercapacitor was fabricated using the highest conducting IL‐doped polymer electrolyte which demonstrates a specific capacitance of 97 F/g with a stable efficiency.

In situ synthesis of AgI on the nanosilica surface for potential application as a cloud seeding material.

A series of nanosilica/AgI composites was synthesized by in situ reactions between silver nitrate and ammonium iodide deposited on the nanosilica surface using the gas-phase solvate-stimulated mechanosorption modification (GSSMSM) under both dry and wet conditions. The characterization of the synthesized materials was performed by X-ray diffraction (XRD), SEM/EDX (Scanning Electron Microscopy-Energy Dispersive X-ray), thermogravimetric (TGA) and gas sorption methods. As a result of the mechanosorption modification of nanosilica, the bulk density of the samples synthesized in the dry and wet medium increases from 45 g/l for initial nanosilica to 249 g/l and 296 g/l for the modified samples, respectively. The specific surface area of the composites decreased in compared to the nanosilica precursor. The SEM data showed a denser aggregate structure of the nanocomposites compared to the initial nanosilica. The XRD, SEM/EDX and TEM/EDX data indicated the formation of AgI clusters. The AgI particle size was in the range of 6-45 nm. The ice-forming activity of the AgI-containing samples was examined as well. The sample with a smaller size of silver iodide on the surface exhibited superior ice-forming properties, and considering the quantity of utilized AgI, the prepared samples hold promise for application in this field.

Iodine-Doped Hollow Carbon Nanocages without Templates Strategy for Boosting Zinc-Ion Storage by Nucleophilicity.

Zn-ion hybrid supercapacitors (ZHCs) combining merits of battery-type and capacitive electrodes are considered to be a prospective candidate in energy storage systems. Tailor-made carbon cathodes with high zincophilicity and abundant physi/chemisorption sites are critical but it remains a great challenge to achieve both features by a sustainable means. Herein, a hydrogen-bonding interaction-guided self-assembly strategy is presented to prepare iodine-doped carbon nanocages without templates for boosting zinc-ion storage by nucleophilicity. The biomass ellagic acid contains extensional hydroxy and acyloxy groups with electron-donating ability, which interact with melamine and ammonium iodide to form organic supermolecules. The organic supermolecules further self-assemble into a nanocage-like structure with cavities under hydrothermal processes via hydrogen-bonding and π-π stacking. The carbon nanocages as ZHCs cathodes enable the high approachability of zincophilic sites and low ion migration resistance resulting from the interconnected conductive network and nanoscale architecture. The experimental analyses and theoretical simulations reveal the pivotal role of iodine dopants. The I5-/I3- doping anions in carbon cathodes have a nucleophilicity to preferentially adsorb the Zn2+ cation by the formation of C+-I5--Zn2+ and C+-I3--Zn2+. Of these, the C+-I3- shows stronger bonding with Zn2+ than C+-I5-. As a result, the iodine-doped carbon nanocages produced via this template-free strategy deliver a high capacity of 134.2 mAh/g at 1 A/g and a maximum energy and power density of 114.1 Wh/kg and 42.5 kW/kg.

Ion Conducting Polyethylene Oxide‐Based Polymer Electrolyte Dopped with Ionic Liquid‐Trifluoromethanesulfonic Chloride

AbstractIn last few decades, polymer electrolyte is the most promising candidate for the fabrication of electrochemical devices. In current work, the influence of adding the room‐temperature ionic liquid (trifluoromethanesulfonic chloride – CClF3O2S) in polyethylene oxide (PEO): ammonium iodide (NH4I) polymer electrolyte has been studied. The IL‐doped polymer electrolyte films are synthesized by solution casting method with varying stoichiometric ratios. Several experimental techniques including optical polarizing microscope, impedance spectroscopy, X‐ray diffraction, Linear sweep voltammetry, Ionic transference number thermal analysis, and electrical conductivity measurements at room temperature have been studied in detail. The complex material's maximum conductivity has been determined to be 3.3 × 10−5 S cm−1 at room temperature. The POM images show the increase in amorphous region which further confirm the improvement in ionic conductivity. Ionic transference number 0.96 shows the system is purely ionic in nature. The ESW of the IL doped polymer electrolyte is also sawed to be 3.32 V which is suitable for the fabrication of electrochemical devices.

Influence of Carbon Black on Conductivity and Structure of Polyethylene Oxide Based Polymer Electrolyte Film

AbstractThe potential applications of carbon black are expected to grow as science and technology improve offering up new possibilities for innovation throughout disciplines included in the field of energy storage. The present work shows the influence of carbon black to improve the ionic conductivity of the polymer electrolyte. The synthesis of polyethylene oxide: ammonium iodide based polymer electrolyte incorporated with carbon black varying from 0.01 to 0.06 wt% with respect to PEO: NH4I system by solution casting method. Different characterizations like polarized optical microscopy (POM), impedance spectroscopy, and ionic transference number (tion) are studied in detail. The maximum ionic conductivity is achieved at 0.05 wt% carbon black shows 1.20 × 10−5 S cm−1 at ambient temperature. In accordance with POM data, the amorphous region has increased whereas the crystalline region has shrunk which further indicated the increase in ionic conductivity. The value of (tion) is calculated to be 0.97 which shows the system is ionic in nature. PEO based polymer electrolyte doped carbon black can be used for the fabrication of energy storage devices.

One-pot FeCl3-catalyzed sustainable synthesis of pyrimidines using ammonium iodide, aldehydes and alkyl lactate as raw materials

Iron(iii)- and iodide-promoted efficient synthesis of pyrimidines from biomass-based alkyl lactates, inorganic ammonium, and aldehydes was carried out.

Resistive switching memories with enhanced durability enabled by mixed-dimensional perfluoroarene perovskite heterostructures.

Hybrid halide perovskites are attractive candidates for resistive switching memories in neuromorphic computing applications due to their mixed ionic-electronic conductivity. Moreover, their exceptional optoelectronic characteristics make them effective as semiconductors in photovoltaics, opening perspectives for self-powered memory elements. These devices, however, remain unexploited, which is related to the variability in their switching characteristics, weak endurance, and retention, which limit their performance and practical use. To address this challenge, we applied low-dimensional perovskite capping layers onto 3D mixed halide perovskites using two perfluoroarene organic cations, namely (perfluorobenzyl)ammonium and (perfluoro-1,4-phenylene)dimethylammonium iodide, forming Ruddlesden-Popper and Dion-Jacobson 2D perovskite phases, respectively. The corresponding mixed-dimensional perovskite heterostructures were used to fabricate resistive switching memories based on perovskite solar cell architectures, showing that the devices based on perfluoroarene heterostructures exhibited enhanced performance and stability in inert and ambient air atmosphere. This opens perspectives for multidimensional perovskite materials in durable self-powered memory elements in the future.

Investigation of suitable buffer layer for PbS-TBAI/PbS-EDT colloidal quantum dot solar cell using SCAPS-1D

Colloidal quantum dots (CQD) are emerging third-generation photovoltaic technologies because of their ability to link a wider range of the light spectrum compared to those of perovskite, crystalline, and copper indium gallium selenide (CIGS) solar cells. In this work, a Lead Sulphide (PbS) CQD solar cell architecture with Ag2S, CdS, ZnSe and ZnS buffer layer is presented. The device consisting of PbS-tetrabutyle ammonium iodide (PbS-TBAI) as an absorber layer, PbS-1,2-ethanedithiol (PbS-EDT) as a hole transport layer (HTL), TiO2 as an electron transport layer (ETL), and fluorine tin oxide (FTO) as an oxide layer. The electrical performances of the solar cells were simulated using SCAPS-1D while taking into account different buffer layers with increasing bandgap values. With ZnS acting as a buffer layer, the computational modelling and analysis of architectural PbS CQD solar cell result in an efficiency of 17.12%. Additionally, the parameters of the solar cell have been studied to be affected by the thickness and bandgap of the absorber and HTL layers, the effect of acceptor concentration with various buffer layers, the impact of temperature, the effect of HTL doping density, and the effect of absorber layer defect density. This study can serve as a guide for future PbS CQD solar cells.