CF3 Group Research Articles

Poly(dicarbon monofluoride) (C2F)n bridges the neutron reflectivity gap

Graphites covalently intercalated with fluorine to form (C2F)n structural type compounds shows a dramatic increase of the interlayer distance up to by a factor of almost 3 to reach ∼9 Å. Such graphite fluoride compounds containing only carbon and fluorine offer the rare opportunity to bridge the so-called gap in the reflectivity of neutron reflectors. Slow neutron reflectors are of great interest in designing neutron sources as well as in fundamental and applied science; they require synthesizing high thermal and chemical compound stability graphite fluorides. In this work, a new strategy is proposed for synthesizing (C2F)n compounds in a well-controlled method. Our results show that the outcome (C2F)n has a covalent character with only sp3 hybridized carbon atoms. Moreover, C–F bonds in the fluorocarbon sheets and CF2 groups on the sheet edges lead to the desired stability and hydrophobic character. A dedicated home-made neutron diffractometer was built for measurements of double-differential neutron cross sections of crystals with specific large interlayer distances found in (C2F)n compounds. We demonstrate that the synthesized fluorine intercalated graphites developed effectively cover the gap in the reflectivity for the new generation of neutron reflectors.

Conformational Preferences of the Non-Canonical Amino Acids (2S,4S)-5-Fluoroleucine, (2S,4R)-5-Fluoroleucine, and 5,5'-Difluoroleucine in a Protein.

Proteins produced with leucine analogues, where CH2F groups substitute specific methyl groups, can readily be probed by 19F NMR spectroscopy. As CF and CH groups are similar in hydrophobicity and size, fluorinated leucines are expected to cause minimal structural perturbation, but the impact of fluorine on the rotational freedom of CH2F groups is unclear. We present high-resolution crystal structures of Escherichia coli peptidyl-prolyl cis-trans isomerase B (PpiB) prepared with uniform high-level substitution of leucine by (2S,4S)-5-fluoroleucine, (2S,4R)-5-fluoroleucine, or 5,5'-difluoroleucine. Apart from the fluorinated leucine residues, the structures show complete structural conservation of the protein backbone and the amino acid side chains except for a single isoleucine side chain located next to a fluorine atom in the hydrophobic core of the protein. The carbon skeletons of the fluorinated leucine side chains are also mostly conserved. The CH2F groups show a strong preference for staggered rotamers and often appear locked into single rotamers. Substitution of leucine CH3 groups for CH2F groups is thus readily tolerated in the three-dimensional (3D) structure of a protein, and the rotation of CH2F groups can be halted at cryogenic temperatures.

Colorless and transparent polyimide nanocomposites using organically modified montmorillonite and mica

In this study, we introduce a method for replacing the glass used in existing display electronic materials, lighting, and solar cells by synthesizing a colorless and transparent polyimide (CPI) film with excellent mechanical properties and thermal stability using a combination of new monomers. Poly(amic acid) (PAA) was synthesized using dianhydride 4,4′-biphthalic anhydride (BPA) and diamine 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane (AHP). Various contents of organically modified montmorillonite (MMT) and mica were dispersed in PAA solution through solution intercalation, and then CPI hybrid films were prepared through multi-step thermal imidization. The organoclays synthesized to prepare CPI hybrid films were Cloisite 93A (CS-MMT) and hexadimethrine-mica (HM-Mica) based on MMT and mica, respectively. In particular, the diamine monomer AHP containing a –OH group was selected to increase the dispersibility and compatibility between the hydrophilic clays and the CPI matrix. To demonstrate the characteristics of CPI, the overall polymer structure was bent and a strong electron withdrawing –CF3 group was used as a substituent. The thermomechanical properties, morphology of clay dispersion, and optical transparency of the CPI hybrid films were investigated and compared according to the type and content of organoclays. Two types of organoclays, CS-MMT and HM-Mica, were dispersed in a CPI matrix at 1 to 7 wt%, respectively. In electron microscopy, most of the clays were uniformly dispersed in a plate-like shape of less than 20 nm at a certain critical content of the two types of organoclays, but agglomeration of the clays was observed when the content was higher than the critical content. Hybrids using HM-Mica had better thermomechanical properties and hybrids containing CS-MMT had better optical transparency.

The CF3 Group as a Synthon of the CF+ Unit in Palladium Chemistry.

The homoleptic trifluoromethyl-palladium(II) complex [Pd(CF3)4]2- (1) is shown to be highly active towards amines. Thus, when treated with primary amines RNH2, it readily undergoes aminolysis of one of the CF3 ligands affording the isocyanide complexes [(CF3)3Pd(CNR)]- (R=aryl). In this process the original CF3 group undergoes total defluorination. Interestingly, the reaction of 1 with secondary amines R2NH proceeds with loss of just two F-substituents, whereby the Fischer-type fluoroaminocarbene complexes [(CF3)3Pd(CFNR2)]- are formed (R=Et, Ph). The reaction of 1 with diamines affords different [(CF3)3Pd(NHC)]- complexes containing sterically non-demanding NHC ligands. Representative examples of various topologies are reported based on the common imidazolidin-2-ylidene or benzimidazolin-2-ylidene rings as well as the expanded-ring perimidin-2-ylidene. This metal-tailored synthetic route, where a CF3 group acts as a pre-carbenic unit, is unprecedented in the vast NHC-chemistry. It takes place under very mild conditions and is envisaged to be extensible to other non-isolable NHC ligands. The key difluorocarbene intermediate [(CF3)3Pd(CF2)]- is experimentally detected.

Phosphine-Catalyzed Domino Annulation of γ-Vinyl Allenoates: Synthesis of Tetrahydrofuro[3,2-c]quinoline Derivatives.

A novel phosphine-catalyzed domino annulation reaction of γ-vinyl allenoates and o-aminotrifluoacetophenones for the construction of terahydrofuro[3,2-c]quinoline derivatives has been developed. In this domino reaction, two kinds of terahydrofuro[3,2-c]quinoline compounds containing CF3 groups were obtained with good yields under mild conditions, three new C-N, C-C, and C-O bonds can be built in one step, and the reaction selectivity is achieved by adjusting the reaction conditions. Furthermore, preliminary studies on an asymmetric variant of this reaction proceeded with moderate enantioselectivity.

The CF3 Group as a Synthon of the CF+ Unit in Palladium Chemistry

AbstractThe homoleptic trifluoromethyl‐palladium(II) complex [Pd(CF3)4]2− (1) is shown to be highly active towards amines. Thus, when treated with primary amines RNH2, it readily undergoes aminolysis of one of the CF3 ligands affording the isocyanide complexes [(CF3)3Pd(CNR)]− (R=aryl). In this process the original CF3 group undergoes total defluorination. Interestingly, the reaction of 1 with secondary amines R2NH proceeds with loss of just two F‐substituents, whereby the Fischer‐type fluoroaminocarbene complexes [(CF3)3Pd(CFNR2)]− are formed (R=Et, Ph). The reaction of 1 with diamines affords different [(CF3)3Pd(NHC)]− complexes containing sterically non‐demanding NHC ligands. Representative examples of various topologies are reported based on the common imidazolidin‐2‐ylidene or benzimidazolin‐2‐ylidene rings as well as the expanded‐ring perimidin‐2‐ylidene. This metal‐tailored synthetic route, where a CF3 group acts as a pre‐carbenic unit, is unprecedented in the vast NHC‐chemistry. It takes place under very mild conditions and is envisaged to be extensible to other non‐isolable NHC ligands. The key difluorocarbene intermediate [(CF3)3Pd(CF2)]− is experimentally detected.

Fluorination effects on non-covalent binding forces: A rotational study on the 2-(trifluoromethyl)acrylic acid–water complex

This study explores the effects of the −CF3 group on non-covalent interactions through a comprehensive rotational investigation of the 2-(trifluoromethyl)acrylic acid–water complex. Employing Fourier transform microwave spectroscopy complemented by quantum chemical calculations, two isomers, i.e., s-cis and s-trans structures, have been observed in the pulsed jet. Based on relative intensity measurements, the s-cis to the s-trans population ratio was experimentally estimated to be ∼ 1:1.2. Subsequently, a comparison of the non-covalent interactions was carried out between the three similar complexes, acrylic acid–water, methacrylic acid–water, and 2-(trifluoromethyl)acrylic acid–water, offering quantitative insights into fluorination affecting the strength of the formed hydrogen bonds important, e.g., in molecular recognition.

A Computational and Spectroscopic Analysis of Solvate Ionic Liquids Containing Anions with Long and Short Perfluorinated Alkyl Chains.

Anion-driven, nanoscale polar-apolar structural organization is investigated in a solvate ionic liquid (SIL) setting by comparing sulfonate-based anions with long and short perfluorinated alkyl chains. Representative SILs are created from 1,2-bis(2-methoxyethoxy)ethane ("triglyme" or "G3"), lithium nonafluoro-1-butanesulfonate, and lithium trifluoromethanesulfonate. Molecular dynamics simulations, density functional theory computations, and vibrational spectroscopy provide insight into the overall liquid structure, cation-solvent interactions, and cation-anion association. Significant competition between G3 and anions for cation-binding sites characterizes the G3-LiC4F9SO3 mixtures. Only 50% of coordinating G3 molecules form tetradentate complexes with Li+ in [(G3)1Li][C4F9SO3]. Moreover, the SIL is characterized by extensive amounts of ion pairing. Based on these observations, [(G3)1Li][C4F9SO3] is classified as a "poor" SIL, similar to the analogous [(G3)1Li][CF3SO3] system. Even though the comparable basicity of the CF3SO3- and C4F9SO3- anions leads to similar SIL classifications, the hydrophobic fluorobutyl groups support extensive apolar domain formation. These apolar moieties permeate throughout [(G3)1Li][C4F9SO3] and persist even at relatively low dilution ratios of [(G3)10Li][C4F9SO3]. By way of comparison, the CF3 group is far too short to sustain polar-apolar segregation. This demonstrates how chemically modifying the anions to include hydrophobic groups can impart unique nanoscale organization to a SIL. Moreover, tuning these nano-segregated fluorinated domains could, in principle, control the presence of dimensionally ordered states in these mixtures without changing the coordination of the lithium ions.

Effects of yak rumen anaerobic fungus Orpinomyces sp. YF3 fermented on in vitro wheat straw fermentation and microbial communities in dairy goat rumen fluid, with and without fungal flora.

Rumen fungi play an essential role in the breakdown of dietary fibrous components, facilitating the provision of nutrients and energy to the host animals. This study investigated the fermentation characteristics and effects on rumen microbiota of yak rumen anaerobic fungus Orpinomyces sp. YF3 in goat rumen fluid, both with and without fungal flora, utilizing anaerobic fermentation bottles. Crushed and air-dried wheat straw served as the fermentation substrate, and cycloheximide was used to eradicate microorganisms from the rumen fluid of dairy goats. The experiment compromised four treatment groups (2×2 factorial design): control (C); yak fungus group (CF, Orpinomyces sp. YF3); goat fungi eliminated group (CA, antibiotic: 0.25 mg/mL cycloheximide); goat fungi eliminated+yak fungus group (CAF). Each treatment had six replicates. Fermentation characteristics and microbial composition of the fermentation media were analyzed using one-way analysis of variance and high-throughput sequencing technology. The findings revealed that in the Orpinomyces sp. YF3 addition group (CF and CAF groups), there were significant increases in ammonia nitrogen concentration by 70%, total volatile fatty acids (VFA) by 53%, as well as acetate, isobutyrate, and valerate concentrations, and the ratio of acetate to propionate (p < 0.05), while the propionate proportion declined by 13%, alongside a reduction of butyrate concentration (p < 0.05). Similarly, in the CF and CAF groups, there were a notable increase in the relative abundance of Bacteroidota, Synergistota, Desulfobacterota, Actinobacteria, and Fusobacteriota, alongside a decrease in the relative abundance of Fibrobacterota and Proteobacteria (p < 0.05). Bacteria exhibiting increased relative abundance were positively correlated with the activity of carboxymethyl cellulase and avicelase, total VFA concentration, and acetate proportion, while showing a negatively correlation with propionate proportion. In conclusion, supplementing rumen fermentation media with yak rumen anaerobic fungus Orpinomyces sp. YF3 led to an increase in bacteria associated with fibre degradation and acetic acid production, a decrease in propionate-producing bacteria, enhanced the activity of plant cell wall degrading enzymes, and promoted cellulose degradation, ultimately elevating total VAF concentration and acetate proportion. This presents a novel approach to enhance roughage utilization in ruminants.

Study on the Compositional Analysis, Extraction Process, and Hemostatic and Anti-Inflammatory Activities of Cirsium japonicum Fisch. ex DC.-Cirsium setosum (Willd.) MB Extracts.

Cirsium japonicum Fisch. ex DC. (CF) and Cirsium setosum (Willd.) MB (CS) are commonly used clinically to stop bleeding and eliminate carbuncles. Still, CF is mainly used for treating inflammation, while CS favors hemostasis. Therefore, the present study used UHPLC-MS to analyze the main chemical constituents in CF-CS extract. We optimized the extraction process using single-factor experiments and response surface methodology. Afterward, the hemostatic and anti-inflammatory effects of CF-CS extract were investigated by determining the clotting time in vitro, the bleeding time of rabbit trauma, and the induction of rabbit inflammation using xylene and lipopolysaccharide. The study of hemostatic and anti-inflammatory effects showed that the CF-CS, CF, and CS extract groups could significantly shorten the coagulation time and bleeding time of rabbits compared with the blank group (p < 0.01); compared with the model group, it could dramatically inhibit xylene-induced ear swelling in rabbits and the content of TNF-α, IL-6, and IL-1β in the serum of rabbits (p < 0.01). The results showed that combined CF and CS synergistically increased efficacy. CF-CS solved the problem of the single hemostatic and anti-inflammatory efficacy of a single drug, which provided a new idea for the research and development of natural hemostatic and anti-inflammatory medicines.

Cu(III)‐CF3 Compound‐Activated DMSO: An Efficient Oxidizing Reagent to Convert Alcohols to Ketones

AbstractIn this study high‐valent Cu(III) trifluoromethyl compounds in combination with DMSO is shown to be an efficient and mild oxidizing system for the conversion of alcohols to ketones (aldehydes as well). Trifluoromethoxylated sulfonium species is proposed to be initially formed that engages in crucial steps of alkoxy replacement at sulfonium center and deprotonative collapse of the resulting alkoxysulfonium intermediate in the presence of a base. This reaction is highly selective without over‐oxidation, and can tolerate a broad range of functional groups owing to mild oxidizing ability of the Cu(III)‐CF3/DMSO system and the inert N2 conditions. This method can be applied to the synthesis and functionalization of commercial drug compounds. This study illustrates an unusual reactivity property of high‐valent Cu(III) trifluoromethyl compounds beyond the conventional CF3 group transfer reactivity, and opens up new opportunities for developing novel reactions of Cu(III)‐CF3 compounds. The combined use of high‐valent Cu(III)‐CF3 compound and DMSO is anticipated to find more applications to develop other novel and useful oxidation reactions.

Passivating Defects via Retarding the Reaction Rate of FAI and PbI2 Enables Stable Perovskite Solar Cells.

The two-step sequential deposition strategy has garnered widespread usage in the fabrication of high-performance perovskite solar cells based on FAPbI3. However, the rapid reaction between FAI and PbI2 during preparation often leads to incomplete reactions, reducing the device efficiency and stability. Herein, we introduced a multifunctional additive, 2-thiophenyl trifluoroacetone (TTA), into the FAI precursor. The incorporation of TTA has proven to be highly effective in slowing the reaction rate between FAI and PbI2, resulting in increased perovskite formation and improved efficiency and stability of the devices. TTA's CF3 groups interact with FAI via hydrogen bonding, effectively suppressing FA+ defects. The S and C═O groups share lone pair electrons with uncoordinated Pb2+, leading to a reduction in perovskite film defects and suppressing nonradiative recombination. Additionally, the CF3 groups impart hydrophobicity, protecting the perovskite film from moisture-induced erosion. As a result, the TTA-modified perovskite film achieves a Champion efficiency of 23.42% compared to the control's 21.52, with 20.58% efficiency for a 25 cm2 solar module. Remarkably, the unencapsulated Champion device retains 86% of its initial PCE after 1080 h under dark conditions (60 ± 5 °C, 35 ± 5% RH), indicating enhanced long-term stability. These findings offer a promising and cost-effective tactic for high-quality perovskite film fabrication.

Structural Analysis of 3,5-Bistrifluoromethylhydrocinnamic Acid

The crystal structure of 3,5-bistrifluoromethylhydrocinnamic acid [systematic name: 3-[3,5-bis(trifluoromethyl)phenyl]propanoic acid], C11H8F6O2, has been determined and described. The structure was subject to the Hirshfeld surface-analysis and CE-B3LYP interaction-energies calculations. The title compound crystallises in the monoclinic P21/c space group with one molecule in the asymmetric unit. The propanoic acid side chain of the studied molecule has a bent conformation. The key supramolecular motif in the crystal structure is a centrosymmetric O–H∙∙∙O hydrogen-bonded dimer (R22(8) in the graph set notation). According to CE-B3LYP, the molecules involved in this motif exhibit the strongest pairwise interaction total energy (Etot = −67.9 kJ/mol). On the other hand, there are seven other interacting molecular pairs with significant Etot values in the range of −17 to −28 kJ/mol. In these, the energy is dominated by the dispersive contribution. A survey of the Cambridge Structural Database revealed that in other 3-phenylpropanoic acid structures, the middle dihedral angle of the propanoic acid side chain is always in the trans conformation. This contrasts the current structure where this dihedral angle is in the gauche conformation. According to the Density Functional Theory calculations in the gas phase (at the B3LYP/aug-cc-pvDZ level), the presence of the two CF3 groups (strong electron-withdrawing character) increases the population of the gauche conformers by a substituent electronic effect, and this may be a minor factor contributing to the appearance of this conformation observed in the solid state.

Psychological wellbeing among parents of a child living with a serious chronic illness: A cross-sectional survey study.

Parents of a child with a chronic illness can experience greater distress than the average population, yet little is understood about differences between illness groups. This cross-sectional survey study aimed to compare parents' psychological distress and perceived wellbeing across five chronic illnesses. Parents from one Australian pediatric hospital completed the Kessler Psychological Distress Scale and seven purpose-designed items about their wellbeing. Data from 106 parents (cancer = 48, cystic fibrosis [CF] = 27, kidney disease = 12, gastrointestinal condition/disorder = 9, developmental and epileptic encephalopathy [DEE] = 10) was analysed using bivariate Pearson's Correlation and linear mixed-effects models. Parents' distress scores differed between groups (F(4,80) = 2.50, p = .049), with the DEE group reporting higher distress than the CF group (mean difference = 6.76, 95% CI [0.11, 13.42]). Distress scores were moderately correlated to parents' perceptions of their child's health and their own wellbeing. Parents' self-reported coping with their child's condition/treatments differed (F(4,81) = 3.24, p = .016), with the DEE group rating their coping as poorer than the CF group (mean difference = -25.32, 95% CI [-46.52, 4.11]). Across all groups, parents reported unmet needs, particularly for psychosocial support and practical/financial assistance. Support interventions may be most effective if tailored to the child's illness, with greater support potentially needed for parents who have a child with DEE and/or severe comorbidities.

Hydrophobic modification of walnut shell biomass-derived porous carbon for the adsorption of VOCs at high humidity

Volatile organic compounds (VOCs) often contain water vapor in their exhaust emissions, resulting in the deterioration of the adsorption capacity of activated carbon (AC). A hydrophobic walnut shell biomass-derived AC using polytetrafluoroethylene (PTFE) and polydimethylsiloxane-coated SiO2 (PDMS/SiO2) was developed to improve the selectivity of VOCs under high humidity conditions. These modified ACs were systematically characterized, and dynamic adsorption behaviors of VOCs such as toluene, acetone and their mixtures at the relative humidity (RH) between 0 and 90 % were conducted. The results showed that walnut shell biomass-derived AC has large specific surface area (1853 m2/g) and total pore volume (1.27 cm3/g), strong hydrophilicity (water contact angle of 6.3°), abundant oxygen-containing groups (OH, CO, CO) and aromatic rings. The coating of PDMS/SiO2-PTFE reduces the surface area and total pore volume of AC, but it creates a double-layer rough structure on the AC surface and introduces CF and SiOSi hydrophobic groups, which achieves a water contact angle of 152.8° for 25PSP/AC. The Yoon-Nelson model is suitable to describe the dynamic adsorption process of single- toluene or acetone under dry/humid condition but not suitable for their mixtures. At RH 90 %, PDMS/SiO2-PTFE modified AC significantly increases the adsorption capacity of toluene but is not obviously improved for acetone, which is due to the different polarity of toluene and acetone. PDMS/SiO2-PTFE films on AC have good thermal stability before 500 °C and the hydrophobicity does not change after multi-regeneration at 200 °C. Therefore, PDMS/SiO2-PTFE modified AC has shown great potential as adsorbent to remove the toluene from the humid condition.

Mechanism of Asymmetric Homologation of Alkenylboronic Acids with CF3-Diazomethane via Borotropic Rearrangement.

Density functional theory calculations have been performed to investigate the mechanism for the BINOL-catalyzed asymmetric homologation of alkenylboronic acids with CF3-diazomethane. The reaction proceeds via a chiral BINOL ester of the alkenylboronic acid substrate. The calculations reveal a complex scenario for the formation of the chiral BINOL-alkenylboronate species, which is the key intermediate in the catalytic process. The aliphatic alcohol additive plays an important role in the reaction. This study provides a rationalization of the stereoinduction step of the reaction, and the enantioselectivity is mainly attributed to the steric repulsion between the CF3 group of the diazomethane reagent and the γ-substituent of the BINOL catalyst. The complex potential energy surface obtained by the calculations is analyzed by means of microkinetic simulations.

Long‐cycling and High‐voltage Solid State Lithium Metal Batteries Enabled by Fluorinated and Crosslinked Polyether Electrolytes

AbstractSolid‐state lithium metal batteries (LMBs), constructed through the in situ fabrication of polymer electrolytes, are considered a critical strategy for the next‐generation battery systems with high energy density and enhanced safety. However, the constrained oxidation stability of polymers, such as the extensively utilized polyethers, limits their applications in high‐voltage batteries and further energy density improvements. Herein, an in situ fabricated fluorinated and crosslinked polyether‐based gel polymer electrolyte, FGPE, is presented, exhibiting a high oxidation potential (5.1 V). The fluorinated polyether significantly improves compatibility with both lithium metal and high‐voltage cathode, attributed to the electron‐withdrawing −CF3 group and the generated LiF‐rich electrolyte/electrode interphase. Consequently, the solid‐state Li||LiNi0.6Co0.2Mn0.2O2 batteries employing FGPE demonstrate exceptional cycling performances of 1000 cycles with 78 % retention, representing one of the best results ever reported for polymer electrolytes. Moreover, FGPE enables batteries to operate at 4.7 V, realizing the highest operating voltage of polyether‐based batteries to date. Notably, our designed in situ FGPE provides the solid‐state batteries with exceptional cycling stability even at practical conditions, including high cathode loading (21 mg cm−2) and industry‐level 18650‐type cylindrical cells (1.3 Ah, 500 cycles). This work provides critical insights into the development of oxidation‐stable polymer electrolytes and the advancement of practical high‐voltage LMBs.

Long-cycling and High-voltage Solid State Lithium Metal Batteries Enabled by Fluorinated and Crosslinked Polyether Electrolytes.

Solid-state lithium metal batteries (LMBs), constructed through the in situ fabrication of polymer electrolytes, are considered a critical strategy for the next-generation battery systems with high energy density and enhanced safety. However, the constrained oxidation stability of polymers, such as the extensively utilized polyethers, limits their applications in high-voltage batteries and further energy density improvements. Herein, an in situ fabricated fluorinated and crosslinked polyether-based gel polymer electrolyte, FGPE, is presented, exhibiting a high oxidation potential (5.1 V). The fluorinated polyether significantly improves compatibility with both lithium metal and high-voltage cathode, attributed to the electron-withdrawing -CF3 group and the generated LiF-rich electrolyte/electrode interphase. Consequently, the solid-state Li||LiNi0.6Co0.2Mn0.2O2 batteries employing FGPE demonstrate exceptional cycling performances of 1000 cycles with 78 % retention, representing one of the best results ever reported for polymer electrolytes. Moreover, FGPE enables batteries to operate at 4.7 V, realizing the highest operating voltage of polyether-based batteries to date. Notably, our designed in situ FGPE provides the solid-state batteries with exceptional cycling stability even at practical conditions, including high cathode loading (21 mg cm-2) and industry-level 18650-type cylindrical cells (1.3 Ah, 500 cycles). This work provides critical insights into the development of oxidation-stable polymer electrolytes and the advancement of practical high-voltage LMBs.

Multi-functional ion-pairing additive for efficient quasi-2D perovskite light-emitting diodes and solar cells

Due to their unique quantum confinement, dielectric coupling, and tunable high-efficiency electroluminescence, quasi-two-dimensional (quasi-2D) perovskite light-emitting diodes (PeLEDs) have attracted considerable attention. However, imperfections in perovskite thin films introduced during the solution-based fabrication process lead to significant non-radiative recombination, hindering device performance. Addressing this challenge is crucial for realizing high-performance quasi-2D PeLEDs. In this study, we introduce an ion-pairing-type additive, 6-maleimidohexanehydrazide trifluoroacetate (EMCH-TFA), designed to cooperatively passivate defects in quasi-2D perovskites. The diverse functional groups (–COOH, –NH2, -CF3) on EMCH-TFA could provide disparate modification to perovskite, among which the CO group tends to coordinate with the uncoordinated Pb2+ ions, thereby passivating the defects in the perovskite crystal. Additionally, the –NH2 and -CF3 groups establish hydrogen bonds with Br- ions and BA+ spacer cations, respectively. This multifaceted approach suppresses the formation of the small n phase and induces alterations in the crystalline state by interacting with numerous sites in perovskites, including A’, B, and X sites. Consequently, the quasi-2D PeLED based on BA2Csn-1PbnBr3n+1 exhibits enhanced brightness, achieving a current efficiency of 66.7 cd/A and an impressive external quantum efficiency of 19.77 %.

Responses of labile organic carbon fractions and mineralized carbon to straw return combined with fertilizer application in the maize–Melilotus officinalis intercropping system

AbstractMollisol is crucial for solving food security issues, but long‐term excessive application of chemical fertilizers has led to severe Mollisol degradation in Northeast China, especially a rapid decline in soil organic carbon (SOC). In context of the use of crop‐herbage intercropping and straw return as alternatives for some chemical fertilizers, it is important to understand how crop‐herbage intercropping and straw return combined with chemical fertilizers influence labile organic carbon (LOC) fractions that improve SOC. To address this, this study explored how the combined application of maize (Zea mays L.)–Melilotus officinalis intercropping, straw return, and chemical fertilizers affect LOC fractions and mineralized carbon (MC) from the perspective of physical property‐mediated pathways. Thus, a field experiment with six treatments was established in the Songnen Plain of Northeast China: (1) maize monoculture without chemical fertilizers and straw return (CK), (2) maize monoculture with chemical fertilizers and no straw return (CF), (3) maize monoculture with chemical fertilizers and straw return (CFS), (4) maize–M. officinalis intercropping and straw return combined with full application of chemical fertilizers (CFSM), (5) maize–M. officinalis intercropping and straw return combined with half application of chemical fertilizers (1/2CFSM), and (6) maize–M. officinalis intercropping and straw return without chemical fertilizers (SM). The CF and CFS groups had no effect on bulk density and porosity but reduced specific gravity. The CFSM group increased water contents, porosity, LOC fractions, SOC, MC, and CO2 release rate and decreased bulk density and specific gravity. Compared with the CF group, the 1/2CFSM group enhanced water contents, microbial biomass carbon, and water‐soluble organic carbon (WSOC) to 6.36%, 17.91%, and 11.6%, respectively. We found that maize–M. officinalis intercropping, straw return, and reducing chemical fertilizers application improved LOC fractions to increase SOC by positively affecting bulk density, specific gravity, and water contents. Further analysis indicated that WSOC was a key determinant of SOC and maize yields. These findings provide a strategy to increase SOC and rehabilitate degraded soils through crop‐herbage intercropping and straw return combined with reducing chemical fertilizers application, which will contribute to a sustainable and environmentally friendly agriculture.