Organic Iodides Research Articles

Metal-Free Photoinitiated, Controlled Cationic Polymerization of Vinyl Ethers Using Organic Iodides

Metal-Free Photoinitiated, Controlled Cationic Polymerization of Vinyl Ethers Using Organic Iodides

Synthesis and scalable process for fabrication of Perovskite Solar Cells using organic and inorganic hole transport materials

The Organic Inorganic Lead Iodide perovskite material has emerged as a pioneer in being an active material for third-generation solar cells. Apart from the synthesis, the scalable mechanism which is being used for the deposition process, greatly influences the performance of the cell owing to its impact on the morphology, uniform thickness, and interface between two functional layers. This study briefly discusses the various deposition processes involved in assembling the layers of perovskite solar cells (PSC). Hole transport materials (HTM) are a crucial part of the PSC providing efficient transport of the charge carriers. However, the effect of organic and inorganic HTMs is highly pronounced in the PSCs. This study also discusses the effect of organic and inorganic HTM on the stability and efficiency of the sandwich-structured PSC.

Extending Shelf-life of Two-step Method Precursor Solutions through Targeted Regulation for Highly Efficient and Reproducible Perovskite Solar Cells.

Precursor solution aging process can cause significant influence on the photovoltaic performance of perovskite solar cells (PVSCs). Notably, we first observe that the aging phenomenon is more severe in the precursor of two-step sequential method compared to that in one-step method due to that the protic solvent isopropanol facilitates amine-cation side reaction and iodide ions oxidation. Herein, we report a novel approach for selectively stabilizing both organic amine salt and lead iodide (PbI2) precursor solutions in two-step method. The introduction of benzene-1,3-dithiol into organic amine salt solution can mitigate amine-cation side reactions due to the formation of an acidic and reducing environment. Simultaneously, decamethylferrocene (FcMe10/FcMe+10) pair can act as a redox shuttle in PbI2 solution to concurrently oxidize Pb0 and reduce I2 in cyclic manner. Consequently, the PVSCs device fabricated from ameliorative precursor solutions demonstrates superior power conversion efficiency of 25.31%, retaining 95% of its efficiency after 21 days of solution aging. Moreover, the unencapsulated devices maintain 85% of primitive efficiency for 1500 h at maximum power point tracking under continuous illumination. This work establishes a fundamental guidance and scientific direction for the stabilization of two-step perovskite precursor solutions.

Mixed low‐dimensional metal halide perovskite single crystal for low‐detection‐limit x‐ray detection via oriented ion migration

AbstractLow‐dimensional metal halide perovskites exhibit exceptional photoelectronic properties and intrinsic stability, positioning them as a promising class of semiconductor materials for light‐emitting devices and photodetectors. In this work, we present a millimeter‐scale single crystal of mixed low‐dimensional (one‐dimensional–zero‐dimensional [1D–0D]) organic lead iodide with well‐defined crystallinity. The fabricated single‐crystal devices demonstrate high‐sensitivity photoresponse and x‐ray detection performance. By spatially isolating organic molecules to form the mixed 1D–0D crystal structure, ion migrations is effectively suppressed, resulting in a remarkable three orders of magnitude reduction in the dark current (56.4 pA @200 V) of the single‐crystal devices. Furthermore, by enhancing the background characteristics, we achieved an impressive low x‐ray detection limit of 154.5 nGys−1 in the single‐crystal device. These findings highlight that the mixed 1D–0D organic lead iodide configuration efficiently controls ion migration within the crystal structure, offering a promising avenue for realizing high‐performance perovskite‐based photodetectors and x‐ray detectors.image

Photoluminescence-Tunable organic phosphine cuprous halides clusters for X-ray scintillators and white light emitting diodes

Low-dimensional cuprous clusters demonstrate fascinating luminescent properties due to their uniquely diversified charge transfer excited states, which imply it could be ideal candidate for multifunctional applications, such as X-ray scintillators and white light emitting diodes (WLED). However, it is still challenge for low-dimensional cuprous clusters that how to regulate the emission performance to meet the requirements of the specific applications. In this work, we prepared a series of luminescent organic cuprous iodide clusters, (IPP)CuI2 and (IPP)2CuI3, which show tunable emission property by simply component regulation. The (IPP)CuI2 with IPP: CuI = 1: 0.75 show the best scintillator property with super-low detection limit of 62.29 nGy/s and high light yields of 75793.83 photons/MeV which is far beyond most organic copper halide scintillators. A series of clear digital radiography (DR) with high spatial resolution of 10.2 lp/mm and a reconstructed 3D model based on computed tomography (CT) were successfully obtained by the prepared scintillation screen. Moreover, the single-component WLED based on accurately component regulation (IPP)CuI2 with IPP: CuI = 1: 0.99 exhibits pure white emission with a high CRI (color rendering index) of 82. The luminescence mechanism of charge transfer excited states in tunable emission (IPP)CuI2 was also investigated. Our works not only provide a kind of ideal materials applied for high-performance single-component WLED and scintillator but also reveal the large potential of low-dimensional organic cuprous halides as luminescent material for multifunctional applications.

Enhancing efficiency of Sb2Se3 solar cell through optimized optical and electrical properties with Bi-layer absorber

In this study, an innovative solar cell utilizing antimony selenide (Sb2Se3) as a base material and incorporating a dual absorber layer is comprehensively examined using the Solar Cell Capacitance Simulator (SCAPS-1D) tool. The aim is to assess the performance of the solar cell with different absorber layers in combination with Sb2Se3. Results demonstrate that the solar cell employing an organic CH3NH3SnI3 absorber layer alongside Sb2Se3 achieves superior efficiency compared to one with an inorganic CZTS absorber layer. The two absorber layers investigated are the inorganic Copper Zinc Tin Sulfide (CZTS) and the organic methylammonium tin iodide (CH3NH3SnI3 The dual absorber layer configuration proves advantageous by enhancing light absorption. The solar cell architecture comprises ZnO/i-ZnO/Sb2Se3/CZTS or CH3NH3SnI3/NiO layers, resulting in an improved efficiency of up to 36.70%. Throughout the analysis, parameters such as concentration, band gap, thickness, and temperature are systematically adjusted to evaluate the behavior of this unique solar cell structure. The findings from the study indicate a noticeable enhancement in the performance of Sb2Se3 solar cells when employing the bilayer absorber structure comprising Sb2Se3 and CH3NH3SnI3.

Photocatalytic [3+2] Cycloaddition of Alkyl/aryl Iodides and Internal Alkynes by Merging Halogen and Hydrogen Atom Transfer

Comprehensive SummaryA visible light photocatalytic [3+2] cycloaddition of alkynes with readily accessible organic iodides as the C3 synthon is developed herein. By merging halogen atom transfer (XAT) and hydrogen atom transfer (HAT), alkyl/aryl iodides serve as a formal diradical precursor and add across C‐C triple bonds to deliver a number of functionalized cyclopentanes in moderate to high yields with exceptional regio‐ and diastereoselectivity. A reductive radical‐polar crossover mechanism, involving the cascade XAT, radical addition, 1,5‐HAT, polar effect‐promoted 5‐endo annulation, single electron transfer (SET) reduction, and protonation, may account for this unprecedented dehalogenative [3+2] cycloaddition. This work not only expands the repertoire of the traditional RATC methodology, but also provides a robust platform for the expedient assembly of cyclopentanes, a valuable structural motif in the realms of medicinal chemistry and material sciences.

Hydrophobic nanosheet silicalite-1 zeolite for iodine and methyl iodide capture

Effective capture of radioactive iodine from nuclear fuel reprocessing is of great importance for public safety as well as the secure utility of nuclear energy. In this work, a hydrophobic nanosheet silicalite-1 (NSL-1) zeolite with an adjustable size was developed for efficient iodine (I2) and methyl iodide (CH3I) adsorption. The optimized all-silica zeolite NSL-1 exhibits an excellent I2 uptake capacity of 553 mg/g within 45 min and a CH3I uptake capacity of 262 mg/g within 1 h. Benefiting from the reduced thickness and enhanced porosity, microporous NSL-1 possesses enhanced iodine adsorption capacity and fast adsorption kinetics, which is a considerable high value among inorganic materials. Unexpectedly, the remarkable characters of high hydrophobicity, acid-resistance and anti-oxidation endow it a higher iodine uptake capacity than traditional aluminosilicate zeolites. More importantly, the high uptake selectivity toward I2 possessed by NSL-1 owing to its hydrophobic skeleton under simulated dynamic conditions. The low cost, facile and scalable synthesis of NSL-1 further highlights great prospects for applications in the nuclear industry. This work provides useful insights for designing efficient adsorbents for iodine capture.

Effects of moisture and aging upon decomposition of methyl iodide by reduced silver mordenite

Reduced silver mordenite has been considered as a sorbent for the capture of organic iodides, especially methyl iodide, from off-gases produced by aqueous used nuclear fuel reprocessing operations. The adsorption capacity of this material has been unpredictable especially when NOx and water are present. Previous work has found that a catalytic decomposition reaction is occurring on the surface but few determinations have been made of the kinetics of this reaction. The work presented tested the adsorption behavior and apparent catalytic reaction rate in humid conditions and compared those to dry conditions testing. Both experiments observed a first order reaction with rate constants of 0.0847 L/g sorbent/s and 0.1202 L/g sorbent/s respectively. Such a reduction in apparent rate constant is possibly due to either water obstructing methyl iodide adsorption or product desorption limitation. Changes in the adsorption profile were also apparent between these two, with the humid conditions experiment reaching saturation sooner than the dry conditions experiment. Additionally, an experiment into the effects of sorbent storage in a controlled laboratory environment was performed. The performance of the sorbent materials that were stored with silver in the zerovalent state was slightly inferior to those materials that were stored in ionic form (Ag+) and reduced to zerovalent silver immediately prior to subjecting them to sorption test. The materials stored with silver in the ionic form (and reduced just prior to application) behaved essentially similarly to the freshly synthesized (and reduced) sorbents in the sorption tests. This suggests that zerovalent silver experiences some oxidation resulting in deactivation of some sites.

Stability Strategies and Applications of Iodide Perovskites.

Iodide perovskites have demonstrated their unprecedented high efficiency and commercialization potential, and their superior optoelectronic properties, such as high absorption coefficient, high carrier mobility, and narrow direct bandgap, have attracted much attention, especially in solar cells, photodetectors, and light-emitting diodes (LEDs). However, whether it is organic iodide perovskite, organic-inorganic hybrid iodide perovskite or all-inorganic iodide perovskite the stability of these iodide perovskites is still poor and the contamination is high. In recent years, scholars have studied more iodide perovskites to improve their stability as well as optoelectronic properties from various angles. This paper systematically reviews the strategies (component engineering, additive engineering, dimensionality reduction engineering, and phase mixing engineering) used to improve the stability of iodide perovskites and their applications in recent years.

Synthesis of different organic ammonium-based bismuth iodide perovskites for photodetection application.

Bismuth-based perovskites are promising candidates for highly stable halide perovskites with low toxicity. Here, we report the synthesis of a series of bismuth iodide-based perovskites with different primary, secondary, and tertiary ammonium cations and study their structural, thermal, and optical properties, and the likelihood of photodetection. Interestingly, the variation of A-site organic ammonium cations, with different interlayer spacings between adjacent bismuth iodide monolayers, has exotic effects on the diffraction patterns and morphological structures of the perovskite crystals. Thermogravimetric analysis reveals the highest thermal stability of tertiary ammonium-based bismuth perovskite with a decomposition temperature of 385 °C. The branched primary ammonium-based photodetector has photo-responsivity roughly two and four times faster than that of secondary and tertiary ammonium-based devices, respectively. These findings provide insight into the importance of A-site cation engineering for structural modulation and tailoring the optoelectronic properties of bismuth-based perovskites for emerging optoelectronic devices.

Improving the performance and stability of perovskite solar cells via surface passivation of phthalimide N-alkylammonium iodides

Phthalimide organic iodide (PAE-I) was first synthesized and introduced onto the surface of perovskite films to enhance the performance of the corresponding PSCs through effectively passivating defects and reducing non-radiative recombination.

Rapid Surface Reconstruction in Air-Processed Perovskite Solar Cells by Blade Coating.

Blade coating has been developed to be an essential technique for large-area fabrication of perovskite solar cells (PSCs). However, effective surface treatment of the perovskite layer, which is a critical step for improving PSC performance, remains challenges during blade coating due to the short interaction time between the modification solution and the perovskite layer, as well as the limited selection of available organic solvents. In this study, a novel modifier N,N-diphenylguanidine monohydrobromide (DPGABr) dissolved in acetonitrile (ACN) is blade coated on the MA0.7 FA0.3 PbI3 surface in air to reconstruct the perovskite surface in hundreds of milliseconds. This work finds that the solvent ACN rapidly dissolves organic iodide of the perovskite layer and leads to a PbI2 -rich surface, providing reactive sites for DPGABr to form a thin DPGABr/PbI2 complex layer. This surface reconstruction can effectively passivate defects and induce n-type doping on the perovskite surface to facilitate electron transfer. The resultant devices show a 15% improvement in average power conversion efficiency. More importantly, the devices with the surface reconstruction show outstanding long-term stability, with negligible performance degradation even after 1-year storage in air. This study presents a convenient and effective approach for improving the performance of blade-coated PSCs prepared in air.

Highly selective monitoring of trace radioactive I2 over organic iodides using NH2-DNA based electrochemiluminescence device

The selective determination of radioactive I2 over organic iodides is beneficial for the efficient treatment of spent fuel and nuclear emergency. We herein develop an efficient strategy for trace I2 selective detection over organic iodide for the first time by using electrochemiluminescence (ECL) device. In detail, an I2 selective sensor is prepared by Au nanoparticles and dsDNA with -NH2 group, and then modified on indium tin oxide (ITO) electrode to obtain I2 detection device. -NH2 acts as ECL co-reactant as well as I2 selective response group, which can specifically combine with I2 in organic iodide atmosphere to quench the signal of ECL emitter (Ru(bpy)32+). This device gives a low limit of detection (5 ng/L) and high selectivity to I2 under high humidity, acidity, temperature as well as CH3I atmosphere. ECL imaging technology is applied to realize visualized accurate monitoring to trace I2 in atmosphere. Electrochemical measurement and theory calculation are further employed to demonstrate the selective mechanism of I2 detection over organic iodides. This work provides an efficient strategy and device for trace I2 specific monitoring, which exhibits a promising prospect in the fields of environment and nuclear energy.

Retention of methyl iodide on metal and TEDA impregnated activated carbon using indigenously developed setup

Removal of methyl iodide (CH3I) from the air present within nuclear facilities is a critical issue. In case of any nuclear accident, there is a great need to mitigate the radioactive organic iodide immediately as it accumulates in human bodies, causing severe consequences. Current research focuses on removing organic iodides, for which the surface of activated carbon (AC) was modified by impregnating it with different metals individually, i.e. Ag, Ni, Zn, Cu and with the novel combination of these four metals (AZNC). After the impregnation of metals, triethylenediamine (TEDA) was coated on metal impregnated activated carbon (IAC) surface. The adsorption capacity of the combination of four metals IAC was found to be 276 mg/g as the maximum for the trapping of CH3I. Whereas TEDA-metal impregnation on ACs enhanced the removal efficiency of CH3I up to 352 mg/g.After impregnation, adsorption capacity of AZNC and AZNCT is significantly higher as compared to AC. According to the finding, t5% of AZNCT IAC is 46 min, which is considerably higher than the t5% of other tested adsorbents. According to isotherm fitting data, Langmuir isotherm was found superior for describing CH3I sorption onto AC and IACs. Kinetics study shows that pseudo second order model represented the sorption of CH3I more accurately than the pseudo first order. Thermodynamic studies gave negative value of ΔG which shows that the reaction is spontaneous in nature. Based on the findings, AZNCT IAC appears to have a great potential for air purification applications in order to obtain clean environment.

Tailoring the Functionality of Additives for Enhancing the Stability of Perovskite Solar Cells

AbstractIn a two‐step procedure for fabricating perovskite films, the PbI2 layer formed on the substrate is converted to perovskite by reacting PbI2 with organic iodide. Excess PbI2 left after forming perovskite composition, however, might have an ill effect on device stability and current–voltage hysteresis, although it positively affects efficiency improvement. Additive engineering is reported here on to control the residual PbI2 in a two‐step procedure. A series of organic multi‐ammonium chloride derivatives are introduced into the PbI2 precursor solution for the first‐step coating, which results in an increase in the perovskite grain size. In addition, carrier lifetime is elongated due to the reduced trap density and the energetics are adjusted to facilitate the extraction of photogenerated carriers. The aminoguanidinium‐containing precursor leads to an improved power conversion efficiency (PCE) as compared to the bare PbI2 precursor mainly due to the significantly enhanced open‐circuit voltage and fill factor. Consequently, a PCE of 23.46% is achieved from the hysteresis‐less photovoltaic parameters and 93% of the initial PCE is maintained after aging for 1000 h in ambient conditions.

Study of Glass Formation and Crystallization Kinetics in a 2D Metal Halide Perovskite Using Ultrafast Calorimetry.

While crystalline 2D metal halide perovskites (MHPs) represent a well-celebrated semiconductor class, supporting applications in the fields of photovoltaics, emitters, and sensors, the recent discovery of glass formation in an MHP opens many new opportunities associated with reversible glass-crystalline switching, with each state offering distinct optoelectronic properties. However, the previously reported [S-(-)-1-(1-naphthyl)ethylammonium]2PbBr4 perovskite is a strong glass former with sluggish glass-crystal transformation time scales, pointing to a need for glassy MHPs with a broader range of compositions and crystallization kinetics. Herein we report glass formation for low-melting-temperature 1-MeHa2PbI4 (1-MeHa = 1-methyl-hexylammonium) using ultrafast calorimetry, thereby extending the range of MHP glass formation across a broader range of organic (fused ring to branched aliphatic) and halide (bromide to iodide) compositions. The importance of a slight loss of organic and hydrogen iodide components from the MHP in stabilizing the glassy state is elucidated. Furthermore, the underlying kinetics of glass-crystal transformation, including activation energies, crystal growth rate, Angell plot, and fragility index, is studied using a combination of kinetic, thermodynamic, and rheological modeling techniques. An inferred fast crystal growth rate of 0.21 m/s for 1-MeHa2PbI4 shows promise toward suitability in extended application spaces, for example, in metamaterials, nonvolatile memory, and optical and neuromorphic computing devices.

Preparation of Highly Conductive Phthalocyaninato-Cobalt Iodide at the Interface between Aqueous KI Solution and Organic Solvent and Catalytic Properties for Electrochemical Reduction of CO2

Abstract For the industrial practical use of cobalt phthalocyanine (CoPc) as a catalyst for CO2 reduction, the effect of improving conductivity of CoPc crystal on the catalytic activity was investigated. Focusing on (phthalocyaninato) cobalt iodide (CoPcI), which is a highly conductive charge-transfer complex, a simple method for synthesizing CoPcI by simply mixing at an interface between aqueous KI solution and CH2Cl2 solution containing CF3COOH and CoPc was developed by applying the CoPc crystal phase transformation method. The X-ray diffraction pattern of the obtained powder at the interface of CoPc organic and potassium iodide aqueous solutions revealed that the powder is composed of one-dimensional columns of CoPc and a linear array of triiodide ions (I3−). UV-vis absorption spectra showed that iodide ions (I−) change to triiodide ions (I3−) at the interface between aqueous KI solution and organic solvent under acidic conditions. The catalytic property of CoPcI was investigated by polarization measurement and electrochemical impedance spectroscopy using a gas diffusion carbon electrode. CoPcI showed high catalytic activity for CO2 reduction with high CO production selectivity.

2,2,2-Trifluoroethanol-Assisted Construction of 2D/3D Perovskite Heterostructures for Efficient and Stable Perovskite Solar Cells Made in Ambient Air.

To achieve future commercialization of perovskite solar cells (PSCs), balancing the efficiency, stability, and manufacturing cost is required. In this study, we develop an air processing strategy for efficient and stable PSCs based on 2D/3D heterostructures. The organic halide salt phenethylammonium iodide is adopted to in situ construct a 2D/3D perovskite heterostructure, in which 2,2,2-trifluoroethanol as a precursor solvent is introduced to recrystallize 3D perovskite and form an intermixed 2D/3D perovskite phase. This strategy simultaneously passivates defects, reduces nonradiative recombination, prevents carrier quenching, and improves carrier transport. As a result, a champion power conversion efficiency of 20.86% is obtained for air-processed PSCs based on 2D/3D heterostructures. Moreover, the optimized devices exhibit superior stability, remaining more than 91 and 88% of their initial efficiencies after 1800 h of storage under dark condition and 24 h of continuous heating at 100 °C, respectively. Our study provides a convenient method to fabricate all-air-processed PSCs with high efficiency and stability.

Organocatalytic Deoxyhalogenation of Alcohols with Inorganic Halides

Direct substitution of alcohols has been a popular topic in organic chemistry. Deoxyhalogenation of alcohols represents one of the most important transformations for accessing organic halides. However, a practical catalytic protocol with readily available, inexpensive, and stable inorganic halides is still unknown. Herein, we report an organocatalytic deoxyhalogenation of alcohols with inorganic halides, which avoids the employment of stoichiometric activators and organic halogenating reagents. Various alcohols are transformed to the corresponding organic bromides and iodides in good yield. Through the one-pot sequential process, C–N, C–O, C–F, C–Cl, and C–S bond formation can also be achieved with good yield.