Halides Research Articles

Sidey V.I. ON THE IONIC RADIUS OF THE CYANIDE ION

Sidey V.I. ON THE IONIC RADIUS OF THE CYANIDE ION

Ion Migration in Lead-Halide Perovskites: Cation Matters.

Metal halide perovskites exhibit remarkable properties for optoelectronic applications, yet their susceptibility to ion migration poses challenges for device stability. Previous research has predominantly focused on the migration of the halide ions. However, the migration of cations, which also has a significant influence on the device performance, is largely overlooked. In this Perspective, we review the migration of cations and their impacts on perovskite materials and devices. Special attention shall be devoted to recent insights into the migration of L-site organic cations in 2D/3D perovskites. We outline inspirations and directions for further research into the cation migration of perovskites, highlighting new possibilities in advancing perovskite optoelectronics.

Ultrafast adsorption of hexavalent chromium from aqueous effluents using covalent triazine frameworks

We have synthesized low-cost high performance covalent triazine framework (CTF) through Schiff base reaction of melamine and terephthalaldehyde with different proportions of the reactants. The synthesized adsorbents showed excellent capacity for adsorption of Cr (VI) at acidic pH while almost negligible adsorption at higher pH. The adsorbent displays excellent reusability, with a little decrease in adsorption capacity with the increasing number of cycles. Moreover, Cr (VI) the adsorption is unaffected by the presence of 50–500 times higher concentration of alkali metal and halide ions in solution, while sulphate ions demonstrate shielding behavior decreasing the adsorption capacity. Mechanistic studies indicate electrostatic attractions, ion exchange and reduction being responsible for the adsorption mediated by abundant nitrogen sites that also imbibes the adsorbent with high capacity. The adsorbent was also utilized to recover chromium from an industrial electroplating effluent, which demonstrates applicability of material for practical applications.

Stepwise Tailoring of Perovskite Nucleation Dynamics and Defect Formation Using a Supersaturation‐Suppression Layer for Developing Efficient and Stable Perovskite Solar Cells

Tailoring crystal growth and defects in perovskites, a viable strategy for suppressing non‐radiative recombination, is widely employed for developing efficient and stable perovskite solar cells (PSCs). However, simultaneous tailoring of crystal growth and defects in PSCs is challenging owing to several limitations; for example, excessive interactions between additives and perovskite precursors impede crystallization, and additive‐induced impurity phases can substantially increase the defect density in perovskite films. In this study, we introduced a metal‐induced supersaturation‐suppression layer (SSL) as a pseudo‐additive interfacial layer to tailor the crystallization dynamics and defect formation in perovskite crystals in steps. The proposed perovskite modification process involves an SSL‐induced metal–halide ion reaction, which modulates the crystallization kinetics for grain growth and enables the formation of metal–halide complex anion adducts that can reduce crystalline defects and suppress non‐radiative recombination while facilitating preferential perovskite crystal growth by alleviating residual strains. Because of these stepwise synergistic effects, the SSL‐based PSCs exhibited significantly improved device performances (23.4%), low hysteresis losses, and enhanced atmospheric operational stability.

Hybrid radical coupling during MnO2-mediated transformation of a mixture of organic UV filters: Chemistry and toxicity assessment

Manganese oxide (MnO2) is one of the most abundant metal oxides, and it is renowned for its ability to degrade various phenolic micropollutants. However, under MnO2-mediated transformation, BP-3 transforms into 12 different radical-coupled transformation products (TPs) out of 15 identified TPs. These radical-coupled TPs are reported with adverse environmental impacts. This study explored the effects of MnO2 on organic UV filter mixtures and different water constituents (i.e., bicarbonate ion (HCO3−), humic acid (HA) and halide ions) in terms of degradation efficiency and transformation chemistry. When a mixture of benzophenone-3 (BP-3) and avobenzone (AVO) underwent transformation by MnO2, hybrid radical-coupled TPs derived from both organic UV filters were generated. These hybrid radical-coupled TPs were evaluated by an in silico prediction tool and Vibrio fischeri bioluminescence inhibition assay (VFBIA). Results showed that these TPs were potentially toxic to aquatic organisms, even more so than their parent compounds. The higher the concentration of HCO3−, HA, chloride ion (Cl−) and bromide ion (Br−), the greater the reduction in the efficiencies of degrading BP-3 and AVO. Contrastingly, in the presence of iodide ion (I−), degradation efficiencies of BP-3 and AVO were enhanced; however, iodinated TPs and iodinated radical-coupled TPs were formed, with questionable toxicity. This study has revealed the environmental risks of hybrid radical-coupled TPs, iodinated TPs and iodinated radical-coupled TPs when the organic UV filters BP-3 and AVO are transformed by MnO2.

Effects of size mismatch of halide ions on the phase stability of mixed halide perovskites

The phase stability of mixed halide perovskites plays a vital role in the performance and reliability of perovskite-based devices and systems. In this work, we incorporate the contribution of the strain energy due to the size mismatch of halideions in Gibbs free energy for the analysis of the phase stability of mixed halide perovskites. Analytical expressions of the chemical potentials of halide ions in mixed halide perovskites are derived and used to determine the critical atomic fractions of halide ions for the presence of spinodal decomposition (phase instability). The numerical analysis of CH3NH3PbI x Br3-x mixed halide perovskite reveals the important role of the mismatch strain from halide ions in controlling the phase instability of mixed halide perovskite, i.e., increasing the mismatch strain widens the range of x for the phase separation of mixed halide perovskites. To mitigate the phase instability associated with the strain energy from intrinsic size mismatch and/or light-induced expansion, strain and/or field engineering, such as high pressure, can be likely applied to introduce strain and/or field gradient to counterbalance the strain gradient by the mismatch strain and/or light-induced expansion.

Adsorptive and Inhibitive Potential of Halide Ions and Plant Extracts from <i>Cucurbita Maxima</i> as Stainless Steel Inhibitors

By utilizing weight loss measurements and electrochemical technique, the corrosion inhibition efficiency of Cucurbita maxima peel and seed extracts on Grade 304 austenitic stainless steel in 1 M sulphuric acid solution was examined. The efficacy of C. maxima extracts' inhibition increased with concentration while decreasing with temperature. At 0.7 g/L extract concentration for 3 hours of immersion, the inhibitor's greatest efficiency was 95.21% for PCM and 94.26% for SCM. Stainless steel corrosion was successfully inhibited by C. maxima peel and seed extracts, according to the results, and it was discovered that the presence of halide ions enhanced the efficacy of the inhibition. The synergistic effect of halide ions was found to follow the order: KI > KCl. According to the polarization curve, C. maxima functions as a mixed-type inhibitor. Due to the extract components' adsorption on the stainless steel surface, peel and seed extracts exhibit an inhibitory effect. The activation energy of the corrosion reaction increases by the presence of both extracts. The physical adsorption is shown by the negative values of ΔGads, which range from -12 kJ/mol to -18 kJ/mol. These values show the spontaneity of the adsorption process. Adsorption is a physical process that adheres to Langmuir adsorption isotherms. The results of a study using scanning electron microscopy to examine the surface morphology of stainless steel in inhibited and uninhibited acid solutions revealed that the presence of extract and halide inhibitors remarkably lowers the corrosion rate. This is as a result of the extract and halide inhibitor molecules adhering to the surface and forming a barrier that prevents an acid attack.

Photophysical Ion Dynamics in Hybrid Perovskite MAPbX3 (X=Br, Cl) Single Crystals

AbstractHybrid organic–inorganic perovskites (HOIPs) are promising candidates for next‐generation photovoltaic materials. However, there is a debate regarding the impact of interactions between the organic center and the surrounding inorganic cage on the solar cell's high diffusion lengths. It remains unclear whether the diffusion mechanism is consistent across various halide perovskite families and how light illumination affects carrier lifetimes. The focus is on ion kinetics of (CH3NH3)PbX3 (X = Br, Cl) perovskite halide single crystals. Muon spectroscopy (μ+SR)is employed to investigate the fluctuations and diffusion of ions via the relaxation of muon spins in local nuclear field environments. Within a temperature range of 30–340 K, ion kinetics are studied with and without white‐light illumination. The results show a temperature shift of the tetragonal‐orthorhombic phase transition on the illuminated samples, as an effect of increased organic molecule fluctuations. This relation is supported by density functional theory (DFT) calculations along the reduction of the nuclear field distribution width between the phase transitions. The analysis shows that, depending on the halide ion, the motional narrowing from H and N nuclear moments represents the molecular fluctuations. The results demonstrate the importance of the halide ion and the effect of illumination on the compound's structural stability and electronic properties.

Stable and Efficient Mixed-halide Perovskite LEDs.

Tailoring bandgap by mixed-halide strategy in perovskites has attracted extraordinary attention due to the flexibility of halide ion combinations and has emerged as the most direct and effective approach to precisely tune the emission wavelength throughout the entire visible light spectrum. Mixed-halide perovskites, yet, still suffered from several problems, particularly phase segregation under external stimuli because of ions migration. Understanding the essential cause and finding sound strategies, thus, remains a challenge for stable and efficient mixed-halide perovskite light-emitting diodes (PeLEDs). The review herein presents an overview of the diverse application scenarios and the profound significance associated with mixed-halide perovskites. We then summarize the challenges and potential research directions toward developing high stable and efficient mixed-halide PeLEDs. The review thus provides a systematic and timely summary for the community to deepen the understanding of mixed-halide perovskite materials and resulting PeLEDs.

Post‐Synthetic Interstitial Metal Doping for Efficient and Stable 3D/2D Heterostructured Perovskite Solar Cells

AbstractPerovskite solar cells (PSCs) have experienced exceptional development in recent years, due to their outstanding photoelectronic properties and low‐cost solution processing. Many state‐of‐the‐art PSC designs have been effectively demonstrated using a stacked 3D perovskite/2D perovskite heterostructure, yet limitations arise due to the low conductivity of the 2D perovskite, the hidden buried interface of 3D perovskite, and halide ion migration within 3D/2D PSC device under operational bias. Here, these limitations are overcome by developing a novel and universal post‐synthetic metal (Zn2+) doping strategy and realizing 3D/2D PSCs with superior efficiency and stability. Informed by ab initio calculations and synchrotron fine structure experiments, it is revealed that the introduced zinc ions are energetically favored at interstitial crystal sites, subsequently hindering the migration of halide ions and producing a beneficial shift toward a more n‐type character in the buried 3D perovskite interface. Combined with extensive photophysical characterization, the Zn2+‐modified 3D/2D perovskite thin film is shown to strongly recover its photo‐carrier conductivity compared with the 3D/2D perovskite film, boosting the efficiency (22.90%) of PSCs while exhibiting improved humidity and operational stability.

Enzyme Engineering Renders Chlorinase the Activity of Fluorinase.

Organofluorine compounds have attracted substantial attention owing to their wide application in agrochemistry. Fluorinase (FlA) is a unique enzyme in nature that can incorporate fluorine into an organic molecule. Chlorinase (SalL) has a similar mechanism as fluorinase and can use chloride but not fluoride as a substrate to generate 5'-chloro-deoxyadenosine (5'-ClDA) from S-adenosyl-l-methionine (SAM). Therefore, identifying the features that lead to this selectivity for halide ions is highly important. Here, we engineered SalL to gain the function of FlA. We found that residue Tyr70 plays a key role in this conversion through alanine scanning. Site-saturation mutagenesis experiments demonstrated that Y70A/C/S/T/G all exhibited obvious fluorinase activity. The G131S mutant of SalL, in which the previously thought crucial residue Ser158 for fluoride binding in FlA was introduced, did not exhibit fluorination activity. Compared with the Y70T single mutant, the double mutant Y70T/W129F increased 5'-fluoro-5-deoxyadenosine (5'-FDA) production by 76%. The quantum mechanics (QM)/molecular mechanics (MM) calculations suggested that the lower energy barriers and shorter nucleophilic distance from F- to SAM in the mutants than in the SalL wild-type may contribute to the activity. Therefore, our study not only renders SalL the activity of FlA but also sheds light on the enzyme selectivity between fluoride versus chloride.

Halide mediated modulation of magnetic interaction and anisotropy in dimeric Co(II) complexes.

The burgeoning interest in the field of molecular magnetism is to perceive the high magnetic anisotropy in different geometries of metal complexes and hence to draw a magneto-structural correlation. Despite a handful of examples to exemplify the magnetic anisotropy in various coordination geometries of mononuclear complexes, the magnetic anisotropies for two different coordination geometries are underexplored. Employing an appropriate synthetic strategy utilizing the ligand LH2 [2,2'-{(1E,1'E)-pyridine2,6-diyl-bis(methaneylylidine)}-bis(azaneylylidine)diphenol] and cobalt halide salts in a 1 : 2 stoichiometric ratio in the presence of triethylamine allowed us to report a new family of dinuclear cobalt complexes [CoII2X2(L)(P)(Q)]·S with varying terminal halides [X = Cl, P = CH3CN, Q = H2O, S = H2O (1), X = Br, P = CH3CN, Q = H2O, S = H2O (2), X = I, P = CH3CN, and Q = CH3CN (3)]. All these complexes are characterized through single crystal X-ray crystallography, which reveals their crystallization in the monoclinic system P21/n space group with nearly identical structural features. These complexes share vital components, including Co(II) centers, a fully deprotonated ligand [L]2-, halide ions, and solvent molecules. The [L]2- ligand contains two Co(II) centers, where phenolate oxygen atoms bridge the Co(II) centers, forming a Co2O2 four-membered ring. Co1 demonstrates a distorted pentagonal-bipyramidal geometry with axial positions for solvent molecules, while Co2 displays a distorted tetrahedral geometry involving phenolate oxygen atoms and halide ions. Temperature-dependent dc magnetic susceptibility measurements were conducted on 1-3 within a range of 2 to 300 K at 1 kOe. The χmT vs. T plots exhibit similar trends, with χmT values at 300 K higher than the spin-only value, signifying a significant orbital contribution. As the temperature decreases, χmT decreases smoothly in all the complexes; however, no clear saturation at low temperatures is observed. Field-dependent magnetization measurements indicate a rapid increase below 20 kOe, with no hysteresis and a low magnetic blocking temperature. DFT and CASSCF/NEVPT2 theoretical calculations were performed to perceive the magnetic interaction and single-ion anisotropies of Co(II) ions in various ligand-field environments.

Polydentate chalcogen bonding: anion trapping with a water-stable host compound carrying Se-CF3 functions.

Bidentate and tetradentate chalcogen bonding host systems with SeCF3 functions as σ-hole donors in close proximity at the alkyne functions of 1,8-diethynylanthracene and its syn-dimer were prepared in quantitative yield by tin-selenium exchange reactions of the corresponding trimethylstannyl precursors with ClSeCF3. The bidentate system shows chalcogen bonding interactions with THF, but does not bind halide ions. The tetradentate system cooperatively chelates chloride, bromide and iodide ions with its four CC-SeCF3 units by rotating the four σ-holes towards the halide ion. The structures of these halide ion adducts were determined by X-ray diffraction. The hydrobromide and -iodide salts of the ethyl derivative of Schwesinger's phosphazene superbase served as halide salts with very weakly coordinating cations.

Copper(I) complexes bearing pyrrole-bridged S,N and N-donor ligands as catalysts for tandem hydroamination-alkynylation: effect of anions on product formation.

In this study, the reaction between 2-(3,5-dimethylpyrazolylmethyl)-5-(dimethylaminomethyl)pyrrole and thiophenol under heating conditions afforded the new ligand 2-(3,5-dimethylpyrazolylmethyl)-5-(phenylthiomethyl)pyrrole 2. The reaction of 2 with meta-chloroperbenzoic acid provided sulfoxide 3 and sulfone 4 group-containing ligands. The reaction of 2 with copper(I) halides provided the binuclear complexes [Cu(μ-X){μ-C4H3N-2-(CH2Me2pz)-5-(CH2SPh)-κ2-S,N}]2 (X = Cl, Br and I, 5-7) in high yields. Conversely, the analogous reaction of 4 with copper(I) halides yielded two types of complexes, three coordinate bi- and mononuclear of the type [Cu(μ-Cl){C4H3N-2-(CH2Me2pz)-5-(CH2SO2Ph)-κ1-N}]28 and [CuX{C4H3N-2-(CH2Me2pz)-5-(CH2SO2Ph)-κ1-N}2], X = Br, 9 and I, 10. When the reaction was carried out in the presence of KPF6, the two-coordinate complex [Cu{C4H3N-2-(CH2Me2pz)-5-(CH2SO2Ph)-κ1-N}2]PF6-11a was isolated, whereas its BF4- analogue 11b was synthesized by the reaction of 8 with AgBF4. The structures of these complexes were determined using single-crystal X-ray crystallography. These copper complexes catalyzed the hydroamination-alkynylation reaction between several secondary amines and alkyl and aryl terminal alkynes. Using 1 mol% of complexes 5-10 as catalysts, both tri- and tetra-substituted propargylamines were isolated. Alternatively, phenylacetylene and different secondary amines afforded the corresponding trisubstituted propargylamines as the major products and alkyl terminal alkynes gave the tetrasubstituted products in excellent yields. In addition, the role of counter anions such as TfO-, PF6-, BF4-, PO43- and Ph4B- on the product selectivity was studied. When fluorinated anions such as TfO-, PF6-, and BF4- were present with the copper complexes, the hydroamination-hydrovinylation product 1-aminodiene 23 was observed, which was not formed with PO43-, Ph4B- or halide ions. Specifically, TfO- and PF6- favored the formation of 23, while BF4- favored the tetrasubstituted product as the major product. This was further supported by the isolated copper(I) complexes containing PF6- and BF4- and by other specific reactions. The peaks for enamines and [LCu]+ species in the HRMS spectra of the reaction mixtures and the isolation of the morpholinium copper(I) salt support the proposed mechanism.

Deciphering the influence of PdII and PdIV oxidation states on non-standard chemical bonds within bis(jN-heterocyclic carbene) complexes: insights from DFT.

Bis-N-heterocyclic carbene ligands (bis(NHC)) have introduced a new approach to designing homogeneous and heterogeneous catalysts, demonstrating the versatility of ligand concepts in catalysis. This study presents a computational analysis of palladium (+ii and +iv) complexes containing either a normally (bis(nNHC)) or an abnormally (bis(aNHC)) bound CH2-bridged bis-N-heterocyclic carbene ligand; in addition, ancillary ligands are permuted from chlorides (X = Cl) to bromides (X = Br). Density functional theory at the B3PW91/6-31G(d)/Lanl2DZ level in the gas phase was used to investigate the electronic structure and bonding properties of bis(NHC)PdIIX2 and bis(NHC)PdIVX4 for bis(NHC) palladium(ii) dihalide and palladium(iv) tetrachloride complexes, respectively. Results indicate that all of the palladium complex structures prefer a flexible boat-type conformation with an average C 2v symmetry, according to bond property (Ccarbene-Pd and Pd-Cl[Br]) analysis. The strength of these bonds depends on coordinating halide ions (Cl- and Br-), the type of ligand (bis(nNHC) and bis(aNHC)), and the palladium oxidation state (+ii and +iv). Analysis of thermodynamic parameters (ΔH 0, ΔG 0, and ΔE bind) shows an increase in values from an abnormal to normal chelating mode in tetrahalides, whereas the opposite is observed for dihalide complexes. The lower π-backbonding ability of the metal, which is influenced by the quantity and size of halide ions involved, could be one possible explanation for this deficiency.

Ga and In-based hybrid halide perovskites as an alternative to Pb: a first principles study.

Lead-free hybrid halide perovskites have gained much attention in the field of photovoltaics due to their non-toxicity, stability and unique photo-physical properties. Sn and Ge-based ABX3 perovskites have been widely studied due to their similar electronic properties to Pb-based materials. However, the unstable oxidation state of Sn is a major challenge for the commercialization of this class of materials. To overcome this problem, here, we have designed a series of novel Ga and In-based A3B2X9-type perovskite materials incorporating the methylammonium (MA) organic cation in the A site and I- as the halide ion in the X site. In this regard, we have investigated different structural, electronic, optical and photovoltaic properties by employing the density functional theory formalism. The formation of a stable three dimensional perovskite structure is determined by the observed values of tolerance factor (TF) and octahedral factor (μ). The observed negative values of formation enthalpy manifest that our studied materials are also thermodynamically stable. The obtained band gap values reveal that our designed perovskite materials can act as semiconducting materials for application in photovoltaics. We have also investigated the optical properties of our studied materials and the observed values of dielectric function and absorption coefficient in the visible range of the electromagnetic spectrum indicate their excellent photo absorption. The observed theoretical power conversion efficiency (PCE) values reveal that (MA)3In2I9 (13.82%) and (MA)3 (Ga.50In.50)2I9 (12.8%) can be chosen as potential candidates for application in perovskite-based photovoltaics. This research provides a pathway for the development of less toxic and efficient semiconducting materials, offering exciting prospects for their utilization in optoelectronics and contributing to the ongoing efforts to advance sustainable energy technologies.

A photoactivated chiral molecular clamp rotated by selective anion binding.

Developing chiral molecular platforms that respond to external fields provides opportunities for designing smart chiroptical materials. Herein, we introduce a molecular clamp whose chiral properties can be turned on by photoactivation. Selective anion binding achieves rational tuning of the conformations and chiroptical properties of the clamp, including circular dichroism and circularly polarized luminescence. Cyanostilbene segments were conjugated to chiral amines with a rotatable axis. Negligible chiroptical signals were significantly enhanced through a light illumination-induced isomerization. Binding with halide ions (F-, Cl- and Br-) enables chiroptical inversion and subsequent amplification of the resulting opposite handedness state by photo treatment. In contrast, the larger I- and NO3 - ions failed to achieve chiroptical inversion. Also the handedness inversion was hampered in conformationally locked amines. Density-functional theory-based computational studies and experimental results reveal a structural transformation that proceeds from a butterfly-like open geometry to a closed V-shaped state initiated by four hydrogen bonds and the rotatable axis. This work illustrates design protocols for use in smart chiroptical molecular platforms mediated by photo treatment and anion binding.

Computational electrocatalysis beyond conventional hydrogen electrode model: CO2 reduction to C2 species on copper facilitated by dynamically formed solvent halide ions at the solid-liquid interface.

The reduction of CO2 into value-added chemicals and fuels has been actively studied as a promising strategy for mitigating carbon dioxide emissions. However, the dilemma for the experimentalist in choosing an appropriate reaction medium and neglecting the effect of solvent ions when using a simple thermochemical model, normally leads to the disagreement between experimental observations and theoretical calculations. In this work, by considering the effects of both the anion and cation, a more realistic CO2 reduction environment at the solid-liquid interface between copper and solvent ions has been systematically studied by using ab initio molecular dynamics and density functional theory. We revealed that the co-occurrence of alkali ions (K+) and halide ions (F-, Cl-, Br-, and I-) in the electric double layer (EDL) can enhance the adsorption of CO2 by more than 0.45 eV compared to that in pure water, and the calculated energy barrier for CO-CO coupling also decreases 0.32 eV in the presence of I ion on a negatively charged copper electrode. The hydrated ions can modulate the distribution of the charge near the solid-liquid interface, which significantly promotes CO2 reduction and meanwhile impedes the hydrogen evolution reaction. Therefore, our work unveils the significant role of halide ions at the electrode-electrolyte interface for promoting CO2 reduction on copper electrode.

Resistive switching in benzylammonium-based Ruddlesden-Popper layered hybrid perovskites for non-volatile memory and neuromorphic computing.

Artificial synapses based on resistive switching have emerged as a promising avenue for brain-inspired computing. Hybrid metal halide perovskites have provided the opportunity to simplify resistive switching device architectures due to their mixed electronic-ionic conduction, yet the instabilities under operating conditions compromise their reliability. We demonstrate reliable resistive switching and synaptic behaviour in layered benzylammonium (BzA) based halide perovskites of (BzA)2PbX4 composition (X = Br, I), showing a transformation of the resistive switching from digital to analog with the change of the halide anion. While (BzA)2PbI4 devices demonstrate gradual set and reset processes with reduced power consumption, the (BzA)2PbBr4 system features a more abrupt switching behaviour. Moreover, the iodide-based system displays excellent retention and endurance, whereas bromide-based devices achieve a superior on/off ratio. The underlying mechanism is attributed to the migration of halide ions and the formation of halide vacancy conductive filaments. As a result, the corresponding devices emulate synaptic characteristics, demonstrating the potential for neuromorphic computing. Such resistive switching and synaptic behaviour highlight (BzA)2PbX4 perovskites as promising candidates for non-volatile memory and neuromorphic computing.

Sodium chloride-assisted CVD enables controlled synthesis of large single-layered MoS2.

Thin-layer MoS2 has attracted much interest because of its potential in diverse technologies, including electronics, optoelectronics and catalysis these few years. In particular, finding a simple and effective solution for large-scale growth of thin-layer semiconductor nanosheets is a prerequisite for achieving their excellent performance. In this paper, we investigated four different substrates under identical conditions for MoS2 film growth and observed a strong correlation between substrate surface conditions and MoS2 growth. To enhance substrate performance, a low-concentration NaCl water solution (25 mg mL-1) was employed for pre-treating the substrate surface, thereby modifying its initial state. In the chemical vapor deposition (CVD) growth environment, the introduced halide ions served as surface dangling bonds. The pre-treated led to a remarkable 90% increase in the growth rate of MoS2 on the substrate surface, facilitating the production of large monolayer MoS2 sheets (∼200 μm). This growth mechanism further enabled the manufacturing of ultra-large single crystals (∼1 mm). Consequently, our research presents a straightforward and cost-effective approach for the large-scale production of nanosheets. Field-effect transistors (FETs) based on the pre-treated monolayer MoS2 exhibited high mobility (12 cm2 V-1 s-1) and a large on/off ratio (104). Therefore, our research provides a simple and low-cost approach for large-scale production of nanosheets for use in high-quality electronics over large areas.