Halides Research Articles

Oxygen-Controlled Electrocatalysis for Selective Dechlorination of 2-Chloro-5-Trichloromethyl Pyridine on Activated Ag Electrode

Electrochemical selective dechlorination can be regarded as one of the most promising strategies for generating high-valued chemicals. In the electrochemical dechlorination process of 2-chloro-5-trichloromethylpyridine (TCMP), except the anticipated dechlorination products involving 2-chloro-5-dichloromethylpyridine (DCMP), 2-chloro-5-chloromethylpyridine (CCMP), and 2-chloro-5-methylpyridine (CMP), some unexpected oxygen-incorporated products (6-chloronicotinic acid (CNA) and 6-chloronicotinoyl methyl ester (MCN)) can be obtained. Consequently, understanding the electrochemical dechlorination behavior of TCMP is crucial. Our research revealed that the activated Ag electrodes in halide ion solution exhibit enhanced electrochemical activities for electrochemical dechlorination of TCMP, compared with the pure Ag owing to the increased active specific surface areas and charge transfer. Second, oxygen participation in the reaction is a necessary condition for the formation of oxygen-incorporated products. A 100% selectivity of oxygen-incorporated products can be obtained at the potential of −0.6 V vs Ag/AgCl. Conversely, insufficient oxygen may lead to the potential becoming the determining condition that affects the reaction pathways. A more negative potential (−1.2 V vs Ag/AgCl) is conducive to the formation of dechlorination products with 94.2% conversion and 100% selectivity. This study, for the first time, elucidates the electrocatalyst, atmosphere, and potential-dependent activity and selectivity for the two dechlorination pathways of TCMP.

Copper (II) halide compounds with cationic N-donor ligands: Design, synthesis, structure and magnetism

Copper (II) complexes of the cationic ligands 1-(4′-pyridyl)-pyridinium (L1) and 1-(4′-pyridyl)-pyridin-4-ol (L2) have been prepared and characterized by single crystal X-ray diffraction and variable temperature magnetic susceptibility measurements: [Cu(L1)2X2]X2 [where X = Cl (1), Br (2)], and [Cu(L2)2X2]X2 [where X = Cl (3), Br (4)]. The complexes are fundamentally square planar with L2X2 coordination planes and long, semi-coordinate bonds to the additional halide ions. All compounds crystallize in monoclinic systems with 1 and 2 in the P21/n space group and 3 and 4 in the P21/c space group. The crystal structures are stabilized by both non-classical (in the case of 1 and 2) and classical (3 and 4) hydrogen bonds. EPR data for 1–4 support a rhombohedral structure, in good agreement with the local geometry as seen in the crystal structures. Magnetic susceptibility measurements show the presence of very weak antiferromagnetic interactions. In addition, the syntheses and magnetic properties of two neutral complexes, [Cu(L3)2X2]·2H2O [L3 = 1-(4′-pyridino)-4-pyridone; X = Cl (5), Br (6)] are reported. Magnetic susceptibility data indicate the presence of moderate antiferromagnetic exchange interactions [J ∼ 28 K (5), 60 K (6)] which were well modeled by the S = 1/2 Heisenberg uniform chain model.

Study of Mechanical, Optoelectronic, and thermoelectric aspects of lithium-based double perovskites Li2AgSbX6 (X=Cl, Br, I) for energy harvesting applications

Inorganic double perovskites appear to be incredible materials for renewable energy purposes, particularly in thermoelectric generators and solar cells. This article systematically examined the stability and various characteristics, including mechanical, thermodynamic, optical, and transport features of Li2AgSbX6 (X=Cl, Br, I), based on density functional theory (DFT) using Wien2k. The finding of formation energy is used to ensure thermodynamic strength and evaluate the tolerance factor for their structural integrity. Mechanical stability is verified by fulfilling the Born criteria involving elastic constants. The directional lattice conductivity and Debye temperature have been assessed using Navier’s velocities. The distinctive optoelectronic characteristics have been explored by adjusting the band gap from 1.40 to 0.49 eV through the varying halide ions (from Cl to I). We also examined various optical features such as absorption bands, refraction, light energy dispersion, and optical loss of the investigated materials. Key thermoelectric characteristics, including the Seebeck effect, conductivities, and performance, have been analyzed across temperatures ranging from 200 to 600 K. The high figure of merit and minimal lattice vibration at room temperature make Li2AgSbX6, double perovskites (DPs), promising for thermoelectric applications.

Force field for halide and alkali ions in water based on single-ion and ion-pair thermodynamic properties for a wide range of concentrations.

A classical non-polarizable force field for the common halide (F-, Cl-, Br-, and I-) and alkali (Li+, Na+, K+, and Cs+) ions in SPC/E water is presented. This is an extension of the force field developed by Loche et al. for Na+, K+, Cl-, and Br- (JPCB 125, 8581-8587, 2021): in the present work, we additionally optimize Lennard-Jones parameters for Li+, I-, Cs+, and F- ions. Li+ and F- are particularly challenging ions to model due to their small size. The force field is optimized with respect to experimental solvation free energies and activity coefficients, which are the necessary and sufficient quantities to accurately reproduce the electrolyte thermodynamics. Good agreement with experimental reference data is achieved for a wide range of concentrations (up to 4 mol/l). We find that standard Lorentz-Berthelot combination rules are sufficient for all ions except F-, for which modified combination rules are necessary. With the optimized parameters, we show that, although the force field is only optimized based on thermodynamic properties, structural properties are reproduced quantitatively, while ion diffusion coefficients are in qualitative agreement with experimental values.

Transformation of p-arsanilic acid by dissolved Mn(III) and enhanced arsenic removal: Mechanism, toxicity and performance in complicated water matrices

Dissolved Mn(III), as a potent one-electron transfer oxidant, is ubiquitous in natural waters and sediments and actively involved in the transformation of organics in biogeochemical processes and water treatment. However, the important role of Mn(III) has long been overlooked because of its short life. This study was the first to investigate the performance of Mn(III) in organoarsenic transformation and to highlight the environmental implications. Both homogeneous and heterogeneous Mn(III)-based systems were effective to remove p-arsanilic acid (p-ASA, 15 μM) with degradation efficiency approaching 40.4 %–98.3 %. Two degradation pathways of p-ASA were proposed, in which As-C bond and amino group were vulnerable sites to Mn(III) attack, leading to the formation of more toxic arsenate (As(V)) and nitarsone. Through transforming organoarsenic to inorganic arsenic species, the removal efficiency of total arsenic and dissolved organics were enhanced to 65.1 %–95.5 % and 16.6 %–36.6 %, respectively, by post-treatment of coagulation or adsorption, accompanied with significant reduction of cytotoxicity and environmental risks. Particularly, polymeric ferric sulfate and granular activated alumina showed superior performance in the total As removal. Moreover, oxidation efficiency of Mn(III) was hardly affected by common cations and anions (e.g., Ca2+, Mg2+, NH4+, NO3ˉ, SO4ˉ), halide ions (e.g., Clˉ, Brˉ) and natural organic matter, showing high robustness for organoarsenic removal under complicated water matrices. Overall, this study shed light on the significance of Mn(III) to the fate of organoarsenics in manganese-rich environments, and demonstrated the promising potential of Mn(III)-based strategies to achieve targeted decontamination in water/wastewater purification.

(C3H7NH3)4Bi1-xSbxI9: 0D hybrid halide perovskite-like compounds with isolated triiodide units.

Antimony/bismuth-based organic-inorganic hybrid halide perovskite-like compounds have generated enormous research interest due to their excellent optical properties. Exploration of new compounds and understanding of their structural stability and optoelectronic properties is of utmost importance for practical applications of these materials. We report two new 0D perovskite-like compounds and their solid solution, (C3H7NH3)4Bi1-xSbxI9, having propyl amine as the spacer cation and iodine as the halide ion. All compounds crystallized in the space group C2/m at room temperature and undergo a phase transition from C2/m to P21/c at low temperature (90 K) as observed from the single-crystal study. A low-temperature (250 K, 180 K, 150 K and 90 K) single-crystal study shows that the (PA)4BiI9 compound retains the monoclinic space group C2/m until 150 K and undergoes a phase transition to the P21/c space group at 90 K. Further, it is observed that ordering, rearrangement and relaxation of the long-chain propyl amine group are primarily responsible for the structural transition. The structure contains [(Bi/Sb)I6]3- polyhedra along with linear I3- units, giving rise to the formula of (PA)3(Bi/Sb)I6·(PA)I3. The I3- units interact poorly while the [MI6]3- (M = Bi, Sb) octahedral units interact significantly with spacer cations via the H-bond, resulting in more distortion in these octahedral units. Theoretical calculations revealed that iodide ions have dual roles and contribute largely to both the valence band maxima and conduction band minima in these compounds. From both experimental and theoretical calculations, it is observed that the pristine compounds are of the indirect band gap-type and Sb substitution in (PA)4Bi1-xSbxI9 led to a gradual decrease in the band gap.

Ultrafast hole transfer mediated by a conjugated self-assembled molecule enables efficient and stable wide-bandgap perovskite solar cells

Charge accumulations and electron recombination at the interfaces between perovskites and charge transporting materials are two critical factors significantly hindering the power conversion efficiency (PCE) and device stability of wide-bandgap perovskite solar cells (WBG PSCs). Herein, we tailor-made a self-assembled molecule (SAM), termed XS13, featuring an enlarged π-donor and a π-linker, to regulate the interface carrier dynamics in ∼1.8 eV WBG PSCs. Ultrafast spectroscopy clearly demonstrated that the XS13 facilitated the rapid extraction and transfer of photo-generated holes compared to the reference SAM-2PACz. Consequently, WBG PSCs based on XS13 achieved an outstanding PCE of up to 19.20 %, surpassing that of control devices (16.41 %). Furthermore, XS13-based WBG PSCs exhibited a remarkable suppression of light/electricity-induced halide ions migration, leading to significantly improved device stability. Our findings offer a new strategy for the rational design of hole transporting molecules with controlled properties to enhance device performance of PSCs.

Effect of Halide Ion Additives during Electrodeposition of Nanocatalysts

Platinum (Pt) and platinum ruthenium (PtRu) alloy catalysts are of interest for the development of green energy technologies such as hydrogen and direct methanol fuel cells. However, the high cost of Pt dictates that the precious metal be used as efficiently as possible so the surface area available to catalyze reactions per mass is maximized. Alloying Pt with different metals such as Ru is also of interest due to the increased activity and tolerance to contaminants that the additional metal imparts to the Pt. Industrial nanoparticle synthesis depends on scalable techniques such as electrodeposition. And a feature of this technique is that the morphology of electrodeposited structures is heavily influenced by the composition of the electrodeposition solution.This work describes how the presence of excess Cl- and Br- ions in an aqueous solution of metal salts affects the morphology of Pt and PtRu electrodeposited onto glassy carbon electrode substrates. The addition Br- ions and mixtures of the two halides resulted in smaller nanoparticles as observed by scanning electron microscopy and, therefore, higher surface areas compared to Pt electrodeposited in the absence of these halide species. Consequently, the mass activity towards the oxygen reduction reaction, one half of the reaction in hydrogen fuel cells, was highest when Pt was electrodeposited in the presence of Br- ions. The PtRu particles were also tested for their activity and resistance to carbon monoxide poisoning as a function of composition and halide additives. These results show that halide ions can be used beneficially in electrocatalyst synthesis without a negative impact on the activity of these catalysts, in contrast to what has been suggested in some prior studies. Presented herein is a simple method to tune the surface area and properties of electrodeposited nanocatalysts.1 Gautam, S.; Hadley, A. M. K.; Gates, B. D. Controlled Growth of Platinum Nanoparticles during Electrodeposition using Halide Ion Containing Additives. J. Electrochem. Soc. 2022, 169, 112508.

Nanometer‐Resolved Mapping of Organic Cation Migration Behavior in Methylammonium Lead Halide Perovskites

AbstractThe performance and stability of organic metal halide perovskite (OMHP) optoelectronic devices have been associated with ion migration. Understanding of nanoscale resolved organic cation migration mechanism would facilitate structure engineering and commercialization of OMHP. Here, we report a three‐dimensional approach for in situ nanoscale infrared imaging of organic ion migration behavior in OMHPs, enabling to distinguish migrations along grain boundary and in crystal lattice. Our results reveal that organic cation migration along OMHP film surface and grain boundaries (GBs) occurs at lower biases than in crystal lattice. We visualize the transition of organic cation migration channels from GBs to volume upon increasing electric field. The temporal resolved results demonstrate the fast MA+ migration kinetics at GBs, which is comparable to diffusivity of halide ions. Our findings help understand the role of organic cations in the performance of OMHP devices, and the proposed approach holds broad applicability for revealing migration mechanisms of organic ions in OMHPs based optoelectronic devices.

(Invited) Ion Migration Influencing Perovskite Solar Cell Performance and Stability

The thermodynamic and redox properties of halide perovskites provide a strong driving force for hole trapping and oxidation of iodide species. When in contact with a non-polar solvent, the migration of iodine species is further extended to expulsion of iodine from the perovskite film. Thus, the mobility of halides and their susceptibility to hole-induced oxidation play a crucial role in determining the long-term stability of metal halide perovskite solar cells. When Ruddlesden-Popper 2D mixed-halide perovskite films with spacer cations such as butylammonium are introduced into three-dimensional (3D) perovskite films, they can stabilize them against moisture-induced degradation at room temperature. While such passivation of 3D perovskites using 2D perovskites has been reported widely, the instability of the 2D/3D interface during long term solar cell operation can be problematic, especially at higher temperatures. The cation migration under light and heat can significantly alter the 2D/3D interface, thus affecting the solar cell performance. We have now probed the cation migration between 2D and 3D perovskites by physically pairing X PbI (X=butylammonium BA, oleylammonium OA, or phenethylammonium PEA) 2D film and (CH3)PbI3 3D film at different temperatures by recording changes in the absorption and emission spectra. Thus, suppression of halide ion migration as well as cation migration remains a key factor in achieving long term stability and improving efficiency of perovskite solar cells and light emitting devices.

Thiourea-Induced Cocrystallization of Mixed-Halide Perovskite Thin Films for High-Performance Pure Blue Perovskite Light Emitting Diodes

Metal halide perovskite light-emitting diodes (PeLEDs) are gaining significant attention towards next-generation display materials owing to their advantageous properties, including color tunability, exceptionally narrow bandwidth, and high luminescence. Recent studies have successfully achieved over 20% external quantum efficiencies (EQE) in green and red PeLEDs. However, the blue PeLEDs lag far behind those of green or red PeLEDs because unstable phase stability in mixed halide perovskite thin films under high turn-on voltage (Von). In specific, the blue emission usually possesses halide ions with smaller ionic radius (Cl- or Br-), which easily migrates under high operative bias generating significant halogen vacancies and phase-transformation. In this context, we suggest thiourea as a promising additive for stabilizing defective perovskite thin films. Thiourea is a well-known hydrogen bond donor to halogens, which allows potential coordination complex of thiourea-halide ions to encompass well-dispersed mixed halides in co-crystallized perovskite lattices. In addition, the strong coordination of the C=S···Pb2+ was also demonstrated the thiourea-incorporated perovskite films, which effectively passivated undercoordinated Pb2+ antisites. Consequently, the thiourea-incorporated perovskite films exhibited stable deep-blue emission within 460 nm, demonstrating excellent luminance and quantum efficiency in pure blue PeLEDs. Moreover, the addition of thiourea achieved decreased Von and excellent spectral stability of pure blue PeLEDs at high applied bias, leading to significant advancements in pure blue perovskite display technology.

Prediction of Halogenated MXenes as Electrode Materials for Halide-Ion Batteries.

Exploring and developing new rechargeable halide-ion batteries plays an important role in the advancement and growth of the ion battery family. Here, we systematically explored the feasibility of single-layer MXenes and their hydrogenated derivatives as electrode materials for halide-ion batteries via first-principles theory. The calculated results indicate that halide ions (T ions) can be stably and efficiently adsorbed on the surfaces of M2X and M2XH2, with theoretical specific capacities ranging from 227 to 497 mAh g-1. The diffusion barriers of the T ion on MXenes are from 0.55 to 0.10 eV, comparable to those of the Li ion in graphite and LiCoO2. The electronegativity of halide anions displays significant impacts on their discharge voltage plateaus on M2X, with the highest voltage up to 5.60 V for the F ion. As a comparison, the hydrogenation of M2XH2 with less surface activity raises a 2-3 V voltage reduction. All MXene-based full cells of TxTi2C|TyTi2CH2 (where x = 0-2 and y = 2-0) and TxTi2N|TyTi2NH2 (where x = 0-2 and y = 2-0) demonstrated high full battery specific energies for F-, Cl-, and Br-ion batteries, up to 462 Wh kg-1. These results demonstrate the potential of new halide-ion battery designs, paving the way for future research and innovation in battery technology.

Hydrogen Absorption and Self-Corrosion of Mg Anode: Influence of Aqueous Electrolyte Species

This review examines the impact of various aqueous electrolytes on hydrogen absorption and self-corrosion in magnesium (Mg) anodes. The discussion integrates both historical and recent studies to explore the mechanisms behind self-corrosion and anomalous hydrogen evolution (HE) under conditions of the Negative Difference Effect (NDE) and Positive Difference Effect (PDE). The focus is on the formation and oxidation of magnesium hydride in regions of active dissolution under NDE conditions. In the case of PDE, anodic dissolution occurs through the passive MgO-Mg(OH)₂ film, which shields the metal from aqueous electrolytes, thereby reducing hydrogen absorption and abnormal HE. The NDE conditions showed delayed reduction activity at the surface, attributed to a hydride phase within the corrosion product layer. Hydride ions were quantified through their anodic oxidation in an alkaline electrolyte, measured by the electric charge passed. The review also considers the role of de-passivating halide ions, electrolyte acidity buffering, and the addition of ligands that form stable complexes with Mg2⁺ ions, on the rates of hydride formation, self-corrosion, and anodic dissolution of Mg. The study evaluates species that either inhibit or promote hydrogen absorption and self-corrosion.

Configurational design of NiPc derivative as electron transport material for stable and efficient perovskite solar cell: DFT and SCAPS-1D framework

In the present work electron transport layer is optimized to achieve the high stability and efficiency of Formamidinium tin iodide (FASnl3) perovskite solar cells (PSCs). Optical and electronic characteristics of designed ETLs were investigated by implying density functional theory. The designed ETLs show improved charge mobility over the nickel phthalocyanines (NiPcs). It has been observed that NiPc, a material for a hole-hole-transporting layer, acts as an electron transport layer in a modified configuration implying electron-withdrawing groups on the hydrogen site. In this study, the electron-withdrawing group (F−, Cl−, Br−, and I−) were substituted in the configuration X8Y8 (X and y are halide ions where X ≠ Y). Among various configurations, F8Br8NiPc demonstrates the maximum charge mobility 50 cm2/Vs Furthermore, the designed ETLs show improved stability over the NiPcs, due to their hydrophobic nature. Optimal characteristics for both the HTL and ETL were achieved to ensure enhanced efficiency. Furthermore, to investigate the impact of various parameters such as thickness, doping density, and defect density of the ETL layer SCAPS-1D numerical simulation was employed. The obtained electron affinity for designed HTL and ETL were found to be 2.4 eV and 4.247 eV respectively. The optimized photovoltaic (PV) characteristics including power conversion efficiency, short-circuit current density (Jsc), and open-circuit voltage (Voc) were found as 30.58 mA/cm2, 1.09 V, and 29.12 % respectively.

Kinetic Assessment of the Catalytic Effect of Halide Ions on the Halogenations of Thiazole and Its Methyl Derivatives in Aqueous Medium

Kinetic Assessment of the Catalytic Effect of Halide Ions on the Halogenations of Thiazole and Its Methyl Derivatives in Aqueous Medium

U(VI) sorption by CTAB/Bent–MOF-74 from various carbonate solutions

CTAB/Bent-MOF-74 was synthesized via hydrothermal method to investigate its U(VI) sorption in carbonate solutions. Generally, CTAB/Bent-MOF-74 (∼87.6 mg·g−1) showed better sorption capacity than CTAB/Bent-MOF-71 (∼64.2 mg·g−1) and CTAB/Bent-CS-35 (∼81.4 mg·g−1) in U(VI)-Cl coexist carbonate solutions when pH = 8.0, [NaHCO3] =2 mmol·L−1, [NaCl] =0.1 mol·L−1 and [U(VI)] =50 mg L−1. The competitive sorption between HCO3−/CO32−, OH−, halide ions and U(VI) complexes ions as well as the weakened electrostatic attraction decreased the composite's uranium sorption efficiency and capacity at high pHinitial, NaHCO3, phosphate, Ca/Mg and halide ions concentrations. The pseudo-second-order kinetics and Langmuir models indicated a monolayer homogeneous chemisorption process. Besides, 0.1mol·L−1 HCl shows the highest desorption efficiency among the selected desorbents, and the sorption rate is still high even after four times of desorption. In particular, the decreasing inhibitory capacity of the halide ions was on the order of I−, F−, Br−, Cl−. Characterization analyzes confirmed the good structural stability and Br anion exchange as well as the -OH/-COOH coordination and electrostatic attraction, which could be the predominant sorption mechanisms of U(VI) by CTAB/Bent-MOF-74. The results provided theoretical references for understanding the uranium sorption in natural uranium-containing water and designing potential uranium-extracting materials.

Spectrally Stable and Bright Red Perovskite Light-Emitting Diodes.

Mixing iodide and bromide in three-dimensional metal-halide perovskites is a facile strategy for achieving red light-emitting diodes (LEDs). However, these devices often face challenges such as instability in electroluminescence spectra and low brightness due to phase segregation in mixed-halide perovskites. Here, we demonstrate spectrally stable and bright red perovskite LEDs by substituting some of the halide ions with pseudohalogen thiocyanate ions (SCN-). We find that SCN- can occupy halogen vacancies, thereby releasing microstrain and passivating defects in the perovskite crystals. This leads to the suppression of mixed-halide phase segregation under electrical bias. As a result, the red perovskite LEDs exhibit a high brightness of >35 000 cd m-2 with stable Commission Internationale de l'Eclairage (CIE) coordinates of (0.713, 0.282). This brightness surpasses that of the best-performing red perovskite LEDs, showing great promise for advancing perovskite LEDs in display and lighting applications.

Arginine-Rich Peptide-Rhodium Nanocluster@Reduced Graphene Oxide Composite as a Highly Selective and Active Uricase-like Nanozyme for the Degradation of Uric Acid and Inhibition of Urate Crystal.

Metal nanozymes have offered attractive opportunities for biocatalysis and biomedicine. However, fabricating nanozymes simultaneously possessing highly catalytic selectivity and activity remains a great challenge due to the lack of three-dimensional (3D) architecture of the catalytic pocket in natural enzymes. Here, we integrate rhodium nanocluster (RhNC), reduced graphene oxide (rGO), and protamine (PRTM, a typical arginine-rich peptide) into a composite facilely based on the single peptide. Remarkably, the PRTM-RhNC@rGO composite displays outstanding selectivity, activity, and stability for the catalytic degradation of uric acid. The reaction rate constant of the uric acid oxidation catalyzed by the PRTM-RhNC@rGO composite is about 1.88 × 10-3 s-1 (4 μg/mL), which is 37.6 times higher than that of reported RhNP (k = 5 × 10-5 s-1, 20 μg/mL). Enzyme kinetic studies reveal that the PRTM-RhNC@rGO composite exhibits a similar affinity for uric acid as natural uricase. Furthermore, the uricase-like activity of PRTM-RhNC@rGO nanozymes remains in the presence of sulfur substances and halide ions, displaying incredibly well antipoisoning abilities. The analysis of the structure-function relationship indicates the PRTM-RhNC@rGO composite features the substrate binding site near the catalytic site in a confined space contributed by 2D rGO and PRTM, resulting in the high-performance of the composite nanozyme. Based on the outstanding uricase-like activity and the interaction of PRTM and uric acid, the PRTM-RhNC@rGO composite can retard the urate crystallization significantly. The present work provides new insights into the design of metal nanozymes with suitable binding sites near catalytic sites by mimicking pocket-like structures in natural enzymes based on simple peptides, conducing to broadening the practical application of high-performance nanozymes in biomedical fields.

Multifunctional Buffer Layer Engineering for Efficient and Stable Wide-Bandgap Perovskite and Perovskite/Silicon Tandem Solar Cells.

Inverted perovskite solar cells (PSCs) are preferred for tandem applications due to their superior compatibility with diverse bottom solar cells. However, the solution processing and low formation energy of perovskites inevitably lead to numerous defects at both the bulk and interfaces. We report a facile and effective strategy for precisely modulating the perovskite by incorporating AlOx deposited by atomic layer deposition (ALD) on the top interface. We find that Al3+ can not only infiltrate the bulk phase and interact with halide ions to suppress ion migration and phase separation but also regulate the arrangement of energy levels and passivate defects on the perovskite surface and grain boundaries. Additionally, ALD-AlOx exhibits an encapsulation effect through a dense interlayer. Consequently, the ALD-AlOx treatment can significantly improve the power conversion efficiency (PCE) to 21.80 % for 1.66 electron volt (eV) PSCs. A monolithic perovskite-silicon TSCs using AlOx-modified perovskite achieved a PCE of 28.5 % with excellent photothermal stability. More importantly, the resulting 1.55 eV PSC and module achieved a PCE of 25.08 % (0.04 cm2) and 21.01 % (aperture area of 15.5 cm2), respectively. Our study provides an effective way to efficient and stable wide-band gap perovskite for perovskite-silicon TSCs and paves the way for large-area inverted PSCs.

Multifunctional Buffer Layer Engineering for Efficient and Stable Wide‐Bandgap Perovskite and Perovskite/Silicon Tandem Solar Cells

AbstractInverted perovskite solar cells (PSCs) are preferred for tandem applications due to their superior compatibility with diverse bottom solar cells. However, the solution processing and low formation energy of perovskites inevitably lead to numerous defects at both the bulk and interfaces. We report a facile and effective strategy for precisely modulating the perovskite by incorporating AlOx deposited by atomic layer deposition (ALD) on the top interface. We find that Al3+ can not only infiltrate the bulk phase and interact with halide ions to suppress ion migration and phase separation but also regulate the arrangement of energy levels and passivate defects on the perovskite surface and grain boundaries. Additionally, ALD‐AlOx exhibits an encapsulation effect through a dense interlayer. Consequently, the ALD‐AlOx treatment can significantly improve the power conversion efficiency (PCE) to 21.80 % for 1.66 electron volt (eV) PSCs. A monolithic perovskite‐silicon TSCs using AlOx‐modified perovskite achieved a PCE of 28.5 % with excellent photothermal stability. More importantly, the resulting 1.55 eV PSC and module achieved a PCE of 25.08 % (0.04 cm2) and 21.01 % (aperture area of 15.5 cm2), respectively. Our study provides an effective way to efficient and stable wide‐band gap perovskite for perovskite‐silicon TSCs and paves the way for large‐area inverted PSCs.