Methyl Ammonium Research Articles

In Situ Potentiometric Monitoring of Nitrate Removal from Aqueous Solution by Activated Carbon and Ion Exchange Resin

A nitrate selective electrode was used for real-time in situ potentiometric monitoring of a batch nitrate removal process using activated carbon and ion exchange resin. A plasticized polymeric membrane consisting of polyvinyl chloride, 2-nitrophenyl octyl ether and tridodecyl methyl ammonium chloride was incorporated into an ion-selective electrode body. First, the dynamic potential response of the electrode to nitrate was investigated. Two commercial activated carbons with different physical properties were then tested. Nitrate removal with these carbons was monitored potentiometrically using several nitrate concentrations. The extreme turbidity of the solutions was not a drawback during potentiometric monitoring of the process, which is a clear advantage over other methods such as optical monitoring. The potential versus time recordings were converted into nitrate concentration versus time plots, which were evaluated with different adsorption kinetic models. A pseudo-second order kinetic model for nitrate adsorption on both activated carbons was found to fit the experimental data very well. The values of the kinetic parameters were very different between the two activated carbons. The proposed methodology was also satisfactorily applied to the study of nitrate removal by an ion exchange resin. In this case, the experimental results clearly follow a pseudo-first order kinetic model. Potential applications of the proposed methodology for monitoring nitrate removal in real water samples are discussed.

Efficient and Stable Wide‐Bandgap Methylammonium‐Free Perovskite Solar Cells by Simultaneous Passivation and Cleaning with Diamine

Wide‐bandgap perovskite solar cells (WBG‐PSCs) are pivotal in achieving high‐performance tandem solar cells. However, their power conversion efficiency (PCE) is limited by the losses from the interfacial charge transfer barrier and nonradiative recombination. In this investigation, 1,4‐bis(aminomethyl)benzene (PDMA) is employed as a defect passivator for fabricating methylammonium (MA)‐free perovskite solar cells (PSCs), thus effectively mitigating nonradiative recombination losses of charge carriers. Meanwhile, PDMA molecules chemically rinse the perovskite film to create a grooved surface, leading to the increase of contact area between the perovskite and electron transport layer to further improve the interfacial charge transfer. As a result, the PSCs based on these surface‐passivated and chemically cleaned perovskite films present a champion PCE of 21.23% (Eg = 1.68 eV) compared to the control devices with a PCE of 18.23%, while maintaining over 80% efficiency after 800 h storage in ambient air. This study presents a highly effective approach for one‐step passivation and chemical cleaning of wide‐bandgap perovskite for efficient and stable solar cells, offering valuable insights for future research in this field.

Homogeneous crystallization of MA-free, wide-bandgap perovskite films via self-assembled monolayer capping for laminated silicon/perovskite tandem solar cells

Methylammonium (MA)-free wide-bandgap perovskite films with improved thermal/light stabilities have gained considerable attention for its application in silicon/perovskite tandem solar cells. However, compared to their MA counterparts, MA-free films often suffer from fast crystallization, resulting in uneven surface morphology, poor crystalline features, and excess PbI2 impurities. To modulate the crystallization dynamics of MA-free wide-bandgap Cs0.22FA0.78Pb(Br0.15I0.85)3 films, this study proposes a self-assembled monolayer (SAM)-capped crystallization strategy, wherein C42H52N6O4RuS2 (Z907) is added to the isopropanol antisolvent in the one-step solution process. The optimized Cs0.22FA0.78Pb(Br0.15I0.85)3 film has a wide bandgap of 1.68 eV with superior morphological/crystalline properties, enhanced thermal/moisture stability, and improved interfacial energy‐level alignment. These favorable characteristics are attributed to the efficient coupling between the positive ion vacancies in the precursor, the −SCN and –COOH functional groups in Z907, and the superhydrophobic nonyl chains in the Z907 SAM. The semitransparent perovskite solar cells (PSCs) built with the optimized Cs0.22FA0.78Pb(Br0.15I0.85)3 films demonstrate substantially high power conversion efficiencies (PCEs) of 21.63 %@0.09 cm2 and 19.12 %@1 cm2. Furthermore, based on the high-efficiency PSCs, the corresponding two-terminal laminated silicon/perovskite tandem solar cells achieved record-high PCEs of 32.07 %@0.09 cm2 and 28.32 %@1 cm2 with negligible hysteresis and improved humidity/thermal stability.

Fabrication of lead halide perovskite solar cells with improved photovoltaic performance using MoSe2 additive strategies

Herein, we reported the fabrication of methyl ammonium lead iodide (MAPbI3) based perovskite solar cells (PSCs). Molybdenum diselenide (MoSe2) was hydrothermally prepared and used as an additive to control the rapid crystallization of MAPbI3. Different weight percentage of (0.1, 0.2, 0.3, 0.4, 0.5 and 0.7%) of the MoSe2 additive was explored to control the crystallization process and improve the surface morphological characteristics of the MAPbI3. The obtained results showed that 0.5% MoSe2 additive modified MAPbI3 based PSCs device demonstrated excellent efficiency of 15.1% with open circuit voltage (Voc) = 0.99 V, photocurrent-density (Jsc) = 21.26 mA/cm2 and fill factor (FF) = 0.72. The fabricated device with 0.5% MoSe2 additive retained more than 85% efficiency whereas pristine MAPbI3 based device retained 49.56% efficiency after 1200 h. This suggested that 0.5% MoSe2 additive modified MAPbI3 based PSCs device has excellent stability compared to the pristine MAPbI3 based PSCs device.

Investigation of UV-blocking and photon-down conversion characteristics of PMMA@ CH3NH3PbBr3:WO3 polymer nanocomposites

Herein, methyl ammonium lead bromide: Tungsten trioxide (CH3NH3PbBr3:WO3) nano heterojunction and polymethyl methacrylate (PMMA) polymer composite films of different weight percentage (wt%) proportions of CH3NH3PbBr3:WO3 nanoparticles (0, 0.5, 1.0, 1.5 and 2.0 wt%) were prepared. The structure, morphology and thermal features of CH3NH3PbBr3:WO3 heterojunctions and PMMA@CH3NH3PbBr3:WO3 nanocomposites were investigated using X-ray diffraction (XRD), Fourier Transform-Infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM) and Differential scanning calorimetry (DSC) techniques. The characterization data revealed decrease in crystallinity (up to 7.97%) and glass transition temperature (Tg) with increase in the concentration of CH3NH3PbBr3:WO3 nanoparticles in PMMA nanocomposites. The UV-visible absorbance and transmittance data of PMMA nanocomposites recorded using UV-visible spectroscopy was used to mathematically deduct the optical characteristics such as absorption coefficient, optical band gap, refractive index, extinction coefficient, finesse coefficient, optical conductivity and Urbach energy. The deducted data revealed improved UV-shielding, refractive index and optical conductivity values while the optical band gap and Urbach energy was found to decrease with concentration of dopant. The experimental data of different PMMA@CH3NH3PbBr3:WO3 composite films showed excellent UV- blocking properties in the wider wavelength range of 259-322nm(4.80eV-3.850eV). The PMMA nanocomposites with 2.0 wt% CH3NH3PbBr3:WO3 filler composition exhibited highest UV-shielding behavior with maximum UV-absorption in the wavelength range of 260 to 300nm. The pristine PMMA films showed a PL emission peak at 410nm while the PMMA nanocomposites exhibited strong emissions in the wavelength range of 485-520nm. The observed hydrophobicity, redshift and longer lifetime decay of 34.3 ns for PMMA nanocomposites is attributed to the incorporated CH3NH3PbBr3:WO3 heterojunction nanoparticles. The chromaticity profile suggested that the emission color changed from blue to green as the filler dose of CH3NH3PbBr3:WO3 varied from 0 to 2.0 wt%. Additionally, the findings from the study reveal that incorporation of CH3NH3PbBr3:WO3 into the PMMA matrix enhances UV-absorption, optical conductivity, hydrophobicity, thermal stability, electrical conductivity and photon-down conversion properties of PMMA which make the material suitable for photonic, photovoltaic, optoelectronic and light emitting diode applications.

Novel ethylbenzyl and hydroxyethyl quaternary ammonium collectors for co-reverse flotation desilication and impurity removal from phosphogypsum: Flotation performance and mechanism

In the reverse flotation process for desilication and impurity removal from phosphogypsum (PG), quaternary ammonium salts are commonly used as cationic collectors, but their selectivity and stability under strongly acidic conditions are limited. In this study, for the first time, dodecyl-dimethyl-ethyl benzyl ammonium chloride (DDEA) and dodecyl-bis(2-hydroxyethyl)-methyl ammonium chloride (2HEAC-12), were used as collectors for the PG co-reverse flotation desilication and impurity removal. Flotation experiments show that both DDEA and 2HEAC-12 collectors exhibit good desilication and impurity removal performance for PG, whereas DDEA shows superior selectivity for quartz than that of 2HEAC-12. When DDEA and 2HEAC-12 were used as collectors, the purity of dihydrate gypsum in obtained PG concentrates was 94.88% and 93.47%, respectively, meeting the first-grade standard for PG used as a building material (GB/T 23456–2018). Adsorption experiments indicate that the adsorption of both collectors on quartz and dihydrate gypsum follows the Langmuir model, suggesting monolayer physical adsorption. Both collectors exhibit a higher selectivity for quartz than dihydrate gypsum. The adsorption process was mainly accomplished by electrostatic interactions and hydrogen bonds. The adsorption process was mainly accomplished by electrostatic interactions and hydrogen bonds. This work provides a viable strategy for developing collectors for PG co-reverse flotation efficient desilication and impurity removal.

Optimizing Formalin Detection in Fish Using QCM Sensors with TOMAC Membrane Coatings for Product Quality Monitoring

<span lang="EN-AU">Detection of formalin in fishery products is a significant concern in the food industry to ensure consumer safety. This study compared the performance of Quartz Crystal Microbalance (QCM) sensors without a membrane and with a Trioctyl methyl ammonium Chloride (TOMAC) membrane coating in detecting formalin in fish samples. The research findings indicate that QCM without a membrane for formalin samples has a lower detection limit of 150 ppm and an upper detection limit of 350 ppm with a sensitivity of 2194.171 Hz/ppm. On the other hand, QCM with a TOMAC membrane coating has a lower detection limit of 400 ppm and an upper detection limit of 550 ppm with a sensitivity of 842.7551 Hz/ppm. Meanwhile, QCM without a membrane for formalin in fish samples has a lower detection limit of 450 ppm and an upper detection limit of 650 ppm with a sensitivity of 15386.38 Hz/ppm. At the same time, QCM with a TOMAC membrane coating for formalin in fish samples has a lower detection limit of 350 ppm and an upper detection limit of 500 ppm with a sensitivity of 23108.9 Hz/ppm. Response time analysis shows that both sensors reach a steady state condition after 12 seconds. This study highlights the importance of selecting appropriate sensors for detecting formalin in fishery products, considering detection limits, sensitivity, and response time as crucial criteria. Thus, these findings can guide the fisheries industry in choosing effective and accurate formalin detection technology.</span>

Control of Methylamine Gas Treatment for Upscaling Perovskite Solar Module

Methylamine (MA0) gas treatment (MATM) is a process that involves the adsorption of MA0 on methylammonium (MA)‐based lead perovskite thin films, forming an adsorption intermediate, which appears as a visually transparent liquid. When MA0 is desorbed from this intermediate, recrystallization of the MA‐based perovskite occurs. Due to the highly reversible nature of MATM and its ability to inherently levelize the film surface through liquefaction, MATM is a promising method for fabricating uniform and intact perovskite thin films over large areas, which is crucial for the commercialization of perovskite solar cells. Herein, efforts to control the MATM process are presented, including slowing down the kinetics of MA adsorption by introducing a diluent into the MA stock solution, establishing a monitoring system to investigate the desorption process in detail, and demonstrating the success of MATM in fabricating perovskite solar modules. It is found that MATM not only heals morphological flaws but also promotes (110) orientation crystallinity and reduces trap density in recrystallized MAPbI3 films. Finally, MATM is applied to prepare perovskite minimodules using an in‐house designed MA‐induced liquefaction and recrystallization reactor. The minimodule (5 × 5 cm) fabricated using MATM achieves 18.32% efficiency, significantly surpassing the performance of those fabricated using antisolvent‐treating (7.50%) and vacuum drying (16.09%) methods.

Mechanistic insights on stabilization and destabilization effect of ionic liquids on type I collagen fibrils

Tuned assembly of collagen has tremendous applications in the field of biomedical and tissue engineering owing to its targeted biological functionalities. In this study, ionic liquids choline dihydrogen citrate (CDHC) and diethyl methyl ammonium methane sulfonate (AMS) have been used to regulate the self-assembly of collagen at its physiological pH by probing the assembled systems at certain concentration ratios of ionic liquids and the systems were studied using various characterization methods. Due to interaction with collagen, choline dihydrogen citrate causes delay in the collagen fibrillisation process showing no binding interactions with collagen. In contrast, diethyl methyl ammonium methane sulfonate shows crosslinking effect on collagen fibrillisation due to the electrostatic interaction with the tetrahedral hydration shell of collagen moieties. From rheological studies it was observed that the AMS treated collagen fibril at 1:1 % (w/v) has highest linear viscoelastic range, this can bear the stress under high strain compare to native collagen fibril as well as all CDHC composites. For a sustainable biomaterial or bio-scaffold, mechanical property plays pivotal role on it and from our experimental analysis we found certain composites of ionic liquid treated collagen fibrillar assembly which may act as a sustainable biomaterial or bio-scaffold. It was also evolved that, how the structure-function relationship of ionic force modulated fibrillar assembly controlling the mechanical properties of the tuned system. This self-assembled, ionic-liquid treated collagen-fibrillar system would accelerate various force modulated fibrillar network study, for mimicking the ECM and tissue engineering application.

Self-passivation of Halide Interstitial Defects by Organic Cations in Hybrid Lead-Halide Perovskites: Ab Initio Quantum Dynamics.

Halide interstitial defects severely hinder the optoelectronic performance of metal halide perovskites, making research on their passivation crucial. We demonstrate, using ab initio nonadiabatic molecular dynamics simulations, that hydrogen vacancies (Hv) at both N and C atoms of the methylammonium (MA) cation in MAPbI3 efficiently passivate iodine interstitials (Ii), providing a self-passivation strategy for dealing with the Hv and Ii defects simultaneously. Hv at the N site (Hv-N) introduces a defect state into the valence band, while the state contributed by Hv at the C site (Hv-C) evolves from a shallow level at 0 K to a deep midgap state at ambient temperature, exhibiting a high environmental activity. Both Hv-N and Hv-C are strong Lewis bases, capable of capturing and passivating Ii defects. Hv-C is a stronger Lewis base, bonds with Ii better, and exhibits a more pronounced passivation effect. The charge carrier lifetimes in the passivated systems are significantly longer than in those containing either Hv or Ii, and even in pristine MAPbI3. Our demonstration of the Hv and Ii defect self-passivation in MAPbI3 suggests that systematic control of the relative concentrations of Hv and Ii can simultaneously eliminate both types of defects, thereby minimizing charge and energy losses. The demonstrated defect self-passivation strategy provides a promising means for defect control in organic-inorganic halide perovskites and related materials and deepens our atomistic understanding of defect chemistry and charge carrier dynamics in solar energy and optoelectronic materials.

NiO/MWCNT incorporated methyl ammonium lead iodide for an efficient perovskite solar cells

The perovskite solar cells (PSCs) reveal the impressive performance due to the extraordinary characteristic features of perovskite material and its fabrication methods. The complex deposition process and hygroscopic nature of hole transport materials are biggest obstacles for attaining high power conversion efficiency (PCE) with long term stability in PSC. In this study, NiO/MWCNT nanocomposites have been synthesized by hydrothermal method and are incorporated in CH3NH3PbI3 to increase the performance of PSCs with stability. The incorporation has been carried out to improve the properties of CH3NH3PbI3 such as formation of large grain size/grain boundaries, reduce the defects that enhance the charge generation/collection and reduction in recombination. The fabricated PSCs with NiO/MWCNT revealed a PCE of 14.93 % with moderate hysteresis, which is significantly higher PCE than that of pristine PSC. The enhanced recombination resistance was observed by electrochemical impedance spectroscopy, which evinces the remarkable PCE of NiO/MWCNT incorporated PSC. The strong PL quenching and red shift of PL spectrum confirms the low recombination and larger grains in the NiO/MWCNT-CH3NH3PbI3 layer. Moreover, the NiO/MWCNT incorporated PSC retains 94 % of its initial PCE after 600 h of aging under atmospheric condition whereas the PCE of pristine PSC shows 87 % of its initial PCE value. The carbon back electrode also supports to lift up PCE and stability of PSCs.

Investigation of synthesis of some ionic liquids from nitrogen compounds and fatty acids of waste oils

In order to reduce the environmental pollution and the dependence on fossil fuel resource which is depleting, the utilization of waste vegetable oils for preparation of valuable products are of concern. Four ionic liquids triethyl ammonium carboxylate ([TEA][WO]), octyl ammonium carboxylate ([OcA][WO]), trialkyl methyl ammonium carboxylate ([Aliquat][WO]) and n-octyl methyl imidazolium carboxylate ([OMIM][WO]) were synthesized from four different nitrogen compounds and fatty acids of waste vegetable oils. The influence of some parameters such as solvent, reaction temperature, reaction time and molar ratio of acid and nitrogen compound (NC) on ionic liquid synthesis yields was investigated. The results show that the structure of nitrogen compounds effects on the synthesis performance and governs the parameters of processes. This is due to the nitrogen compounds as starting materials control not only their activity in reaction with fatty acids but also the solubility and the melting points of corresponding ionic liquids. Certain suitable conditions were chosen for each ionic liquid.

Synthesis and Characterization of New Copper(II) Coordination Compounds with Methylammonium Cations

We synthesized four new copper(II) complexes with acetato and chlorido ligands and methylammonium (MA), dimethylammonium (DMA), and tetramethylammonium (TMA) counterions: (MA)4[Cu2Ac4Cl2]Cl2·2H2O (1), (DMA)2[Cu2Ac4Cl2] (2), (DMA)4[Cu2Ac4Cl2]Cl2·2H2O (3), and (TMA)5[Cu2Ac4Cl]Cl4·4H2O (4). All compounds were characterized by single-crystal X-ray diffraction, magnetic measurements, FTIR spectroscopy, and thermogravimetric analysis. Complexes 1, 2, and 3 consist of a dinuclear coordination anion [Cu2(Ac)4Cl2]2− with bridging acetato ligands arranged in a paddle-wheel conformation and square-pyramidal coordination around Cu(II) atoms, while the coordination anion in compound 4 is a polymeric chain, parallel to the c axis, with Cu2(Ac)4 units connected through bridging chlorido ligands. Magnetic measurements carried out between 2 K and 300 K indicate strong antiferromagnetic interactions between Cu(II) ions. The effective magnetic moments range from 1.94 μB to 2.21 μB, exceeding the spin-only value for Cu(II) ions (μeff=1.73 μB) and suggesting significant orbital contributions to the magnetic moment. Thermogravimetric analysis of all complexes showed a multistep decomposition behavior yielding elemental copper as the final product.

Bandgap Engineering via Doping Strategies for Narrowing the Bandgap below 1.2 eV in Sn/Pb Binary Perovskites: Unveiling the Role of Bi3+ Incorporation on Different A-Site Compositions.

The integration of perovskite materials in solar cells has garnered significant attention due to their exceptional photovoltaic properties. However, achieving a bandgap energy below 1.2 eV remains challenging, particularly for applications requiring infrared absorption, such as sub-cells in tandem solar cells and single-junction perovskite solar cells. In this study, we employed a doping strategy to engineer the bandgap and observed that the doping effects varied depending on the A-site cation. Specifically, we investigated the impact of bismuth (Bi3+) incorporation into perovskites with different A-site cations, such as cesium (Cs) and methylammonium (MA). Remarkably, Bi3+ doping in MA-based tin-lead perovskites enabled the fabrication of ultra-narrow bandgap films (~1 eV). Comprehensive characterization, including structural, optical, and electronic analyses, was conducted to elucidate the effects of Bi doping. Notably, 8% Bi-doped Sn-Pb perovskites demonstrated infrared absorption extending up to 1360 nm, an unprecedented range for ABX3-type single halide perovskites. This work provides valuable insights into further narrowing the bandgap of halide perovskite materials, which is essential for their effective use in multi-junction tandem solar cell architectures.

Observation of Hot Carrier Localization Affected by A Cations in Hybrid Perovskites.

Organic-inorganic lead halide perovskites (OLHPs) have demonstrated exceptional properties in high-performance photoelectric devices. However, the impact of A-site cations, specifically formamidinium and methylammonium (MA), on the optoelectronic properties of OLHPs, particularly in the context of hot carrier utilization, remains a topic of debate. In this study, we propose a method for characterizing hot carrier transportation by measuring the hot carrier mobility and momentum-dependent transient photocurrent influenced by A-site cations in OLHPs. Our findings reveal that the direction of photon drag current is reversed upon substitution of the MA cation, suggesting the strong localization of hot carriers by the MA cation dipole. Furthermore, the correlation between the hot carrier photoconductivity and the electronic structure in different A-site cation samples indicates that hot carrier mobility in OLHPs can be reduced by >50% due to the influence of A-site cations.

Investigating the influence of the Ag and Al co-doping in ZnO electron transport layer on the performance of organic-inorganic perovskite solar cells using experimentation and SCAPS-1D simulation

The sufficient material selection of electron transport layer (ETL) enormously promises exceptional conversion efficiency from perovskite (PVT) solar cells (PSCs), which in turn give rise to their rapid establishment in world-wide photovoltaic (PV) market. Among the tactics exerted on ETLs, and thus, intensifies the adequacy of associated PSCs, the methodology of doping stands productive. Therefore, this research validates the implementation of such effectual ETLs on widely approved methyl ammonium lead triiodide (MAPbI3)–based PSCs. The work brings together two versions of zinc oxide (ZnO) ETLs: one in its pristine form, and the other is aluminum (Al) co-doped with silver (Ag) represented as Ag-AZO. The investigation launches the PV capabilities of Ag-AZO ETL against its undoped correspondent. Accordingly, the earlier part of the investigation centers on the experimental assessment of ZnO and Ag-AZO nanoparticles (NPs) affirming their material and morphological aspects. Later, the research deals with the involvement of both NPs as ETLs signifying the PV potential of MAPbI3–based PSCs through comprehensive numerical analysis. The judgements of investigation declare that MAPbI3–based PSC with Ag-AZO ETL yields a desirable power conversion efficiency (PCE) of 27.26% against 25.98% from control cell. The investigation will definitely enlighten the development of forthcoming efficient PSCs incorporated with appropriate multiple metals co-doped ETLs.

Numerical simulation of lead-free MASnI3 perovskite/silicon heterojunction for solar cells and photodetectors

Lead free n-type doped methyl ammonium tin iodide (MASnI3) perovskite/p-Silicon heterojunction (HJ) for solar cells and photodetectors are simulated using AFORS-HET automat simulation software. In the earlier work, lead based methyl ammonium lead iodide perovskite/silicon (n-MAPbI3/p-Si) heterojunction devices were studied. In view of the toxicity and environmental concerns related to lead, it is substituted with tin to make lead-free tin based perovskite to make n-MASnI3/p-Si HJ devices. Various parameters associated with the layers of MASnI3 perovskite and silicon wafer like, Band gap, thickness, doping concentration and texturing angle have been optimized. Various transparent conducting oxide (TCO) materials like indium tin oxide (ITO) and zinc oxide (ZnO) are used and its performance with ideal device is compared. Various metals are considered as front and back contact, to obtain best metals for each sides. This study investigates the potential of lead-free perovskite materials in solar cells, achieving a notable efficiency improvement compared to traditional lead-based counterparts. Our numerical simulations demonstrate that the optimized lead-free perovskite with structures, n-MASnI3/p-Si heterojunction can reach efficiencies of 27.2%. These findings suggest that lead-free perovskites could serve as a viable, environmentally friendly alternative in the photovoltaic industry.

Exploring eco-friendly novel charge transport materials for enhanced performance of tin based perovskite solar cell

This pioneering simulation study explores the potential of perovskite materials, particularly the non-toxic methyl ammonium tin iodide (MASnI3), in solar cell technology. The investigation focuses on eco-friendly, solution-processed compounds—specifically, WO3 and In2S3 as Electron Transport Layers (ETL) and MoO3 and WSe2 as Hole Transport Layer (HTL)—to develop planar n-i-p MASnI3 perovskite solar cell (PSC) devices. WO3 is chosen for its solution processing and high electron mobility, while In2S3 offers n-type properties, superior carrier mobility, non-toxicity, and thermal durability. MoO3 and WSe2 are selected as HTLs for their efficient charge transport capabilities. Utilizing the solar cell capacitance simulator (SCAPS-1D) software, the study systematically evaluates alternative charge-selective materials, considering various parameters such as thickness (0.1 µm to 1.5 µm for absorber and 0.1 µm to 0.35 µm for CTLs), doping concentration (3.2E10 to 3.2E16 for absorber and E16 to E20 for CTLs), defect density, and energy band offset for MASnI3 PSCs. Four distinct n-i-p device structures are optimized, yielding impressive PCE improvements ranging from 14.63 % to 25.34 %, a significant 3 % enhancement compared to initial results. Notably, the WO3/MASnI3/WSe2 configuration exhibits limitations in electrical performance, while the other optimized structures demonstrate substantial efficiency gains. Further analysis investigates the impact of reflecting coatings (10 % to 90 %), varying contact work functions (5.2–5.8 eV), and temperature (300–400 K) on photovoltaic parameters. Critical factors including energy band offset, recombination current profile, and built-in potential, are meticulously examined, laying the groundwork for advanced PSC implementation. The study culminates in the In2S3/MASnI3/MoO3 device configuration, which achieves a peak efficiency of 25.34 %, showcasing superior thermal stability and an enhanced fill factor, thus propelling all-inorganic PSCs towards practical implementation.

Impact of Structural Strain on Performance of Halide Perovskite Solar Cells: A Combined DFT and SCAPS‐1D Analysis

AbstractThe halide perovskites have received extensive experimental and theoretical research interests for photovoltaic application. Most of the theoretical research is based on either material or device modeling approaches. However, literature is still deprived of studies based on the combination of these approaches, which are expected to yield predictions with superior accuracy. This report combines the first‐principles density functional theory (DFT) computations and device modeling to understand the impact of structural strain, generally induced during the crystallization phase of perovskite materials, on the photovoltaic performance of methyl ammonium lead halide (CH3NH3PbI3 or MAPbI3) based solar cell. The magnitude of strain varies in the range from +2% (tensile) to −2% (compressive). The impact of strain is analyzed in terms of the variations in band structure and values of optoelectronic parameters obtained using DFT calculations and further, their impact on performance metrics of solar cells is predicted using device simulations. The optimized cell efficiency under strain‐free conditions is 13% while it deteriorated to 1.6% under +2% tensile strain and improved to 22.3% under compressive strain. The simulation results underline the importance of engineering the structural strain during the crystallization of perovskite absorber material to achieve solar photovoltaic cells of high efficiency.

Understanding the Mechanisms of Methylammonium-Induced Thermal Instability in Mixed-FAMA Perovskites.

Despite a recent shift toward methylammonium (MA)-free lead-halide perovskites for perovskite solar cells, high-efficiency formamidinium lead iodide (FAPbI3) devices still often require methylammonium chloride (MACl) as an additive, which evaporates away during the annealing process. In this article, it is shown that the residual MA+, however, triggers thermal instability. To investigate the possibility of an optimal concentration of MA+ that may improve thermal stability, the intrinsic thermal stability of pure FA, FA-rich, MA-rich, and pure MA perovskite films (FA1-xMAxPbI3, FAMA) is studied. The results show that the thermal stability of FAMA perovskites decreases with more MA+, under degradation conditions that isolate the intrinsic thermal stability of the material (i.e., without moisture and oxygen effects). X-ray diffraction (XRD), proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS), photoluminescence (PL) and UV-visible spectroscopy, and depth-profiling X-ray Photoelectron Spectroscopy (XPS) are employed to show that the observed trend is mainly due to the decomposition of the MA+ cation, as opposed to other effects such as the precursor solvent and film morphologies. It is also found that the surfaces of these FAMA films are MA+ rich, although this phenomenon does not appear to affect thermal stability. Finally, it is demonstrated that this trend is unaffected by the presence of Spiro-OMeTAD atop the film, and thus solar cell devices should preserve this trend.