Water Molecules Research Articles

Engineering the defects of UiO-66 MOF for an improved catalytic detoxification of CWA simulant: methyl paraoxon.

Exigency in search of an ideal candidate for an effective detoxification of chemical warfare agents is still continuing. Zirconium-based Metal-organic Framework (MOF) UiO-66 has shown a significant detoxification of such toxic chemicals owing to its tunable physio-chemical properties and profuse catalytic sites. In this context, a series of UiO-66 MOFs synthesized by tuning the acidity constant (pK a) and concentration of the modulator, synthesis temperature and water molecules was tested for their detoxification efficiency against the simulant 'methyl-paraoxon' at room temperature. Amongst, HCl modulated UiO-66 across the considered synthesis temperature have shown competent catalytic performance in virtue of defects generation within its structure. In addition, the role of catalytic features of UiO-66 obtained by tailoring its defects in enhancing the degradation efficiency has been systematically investigated. The detoxification efficiency of 98.5% with a half-life time of 0.23 min has confirmed the effectiveness of engineered defects in enhancing the catalytic activity of UiO-66 in detoxifying the identified simulant.

Designing highly tunable anion responsive Cardin-motif peptide based self-assembled nanostructures for accessing diverse cellular response

Several anions present in the extracellular matrix (ECM) not only have significant physiological functions in ECM but also play an important role in regulating peptide-based self-assembly. Herein, we have employed a non-conventional approach to overcome the limitations of the positively charged Cardin-motif peptide that failed to self-assemble at physiological pH. We used a simple and elegant strategy by employing different anions such as HPO42-, Cl- and I- to mask the overall surface charge of peptide. Interestingly, these anions were utilized to modulate the nanostructure formation and mechanical stiffness of peptide hydrogels owing to their differential interactions with water molecules according to the Hofmeister series. Interestingly, these anions-induced hydrogels showed diverse cellular responses on two different cell lines, fibroblast and neuronal, indicating diverse application potential of the new scaffold. Thus, this study emphasizes the importance of anions to regulate the self-assembly of Cardin-motif peptide and this approach can be utilized in developing the ideal biomimetic model of ECM for futuristic applications.

Ni-based compounds in multiwalled graphitic shell for electrocatalytic oxygen evolution reactions

Here, we report a general strategy for designing a metal/carbon system, via a facile and environmentally friendly one-step approach, from metal acetate as an active electrocatalyst in oxygen evolution reaction (OER) during water decomposition. As a demonstration, a nanostructured Ni/C composite induced from nickel acetate is revealed in great detail. The resulting material is composed of: metallic nickel (Ni), nickel(II) oxide (NiO), and nickel carbide (Ni3C) coated with a graphitic shell and deposited on a carbon platform. Our findings underscore the prominent role of nickel species, including Ni0, Ni2+, and Ni3+, in driving the catalytic activity. Notably, the catalyst exhibits an overpotential of 170 mV, a Tafel slope of 49 mV·dec−1, an electrocatalytic surface area (ECSA) of 964.7 cm2, and a turnover frequency (TOF) value of 52.8 s−1, surpassing RuO2. The Raman spectra also suggest a graphitic "self-healing" phenomenon post-OER, attributed to the reduction of oxygen-containing groups. Carbon in the system (i) facilitates electron transfer, (ii) allows homogeneous distribution of Ni nanoparticles avoiding their agglomeration, and (iii) promotes durability of the electrocatalyst by serving as a protective barrier, shielding the core metal compounds. What is more, density functional theory (DFT) calculations allowed to optimized geometry of the model cluster Ni8O8(OH)8 describing two different sites on the β-NiOOH surface (001) and two different intermediates, (i)L-OOH and (ii)L-OOH. This facilitated to propose the reaction mechanisms involving both hydroxide ions and water molecules as reducers. Therefore, the chemisorption of OH− and H2O molecules at the NiOOH active center accompanied by bond breakage and the formation of a lattice hydroperoxide as an important intermediate is presumed. What is more, the proposed fabrication method for electroactive metal/carbon composites was validated with an iron and iron/nickel mixture.

Icelike water molecules with single hydrogen bond donor on the surface of nano anatase and rutile particles by IR spectroscopy

The hydration behavior of TiO2 nanoparticles was studied by molecular dynamics simulations and a novel IR ratio spectroscopy method. It was found that the hydration water at the titanium dioxide interface contains molecules with a large number of single hydrogen bond donors, and approximately five water layers were confined within the nano-grooves of the nanoparticles. The confinement effect was observed to enhance the strength of the hydrogen bonds and to slow down the movement of the water molecules around the surface of the nanoparticles.

Investigating the effectiveness of graphene oxide and hydroxylated hexagonal boron nitride to improve the coating corrosion resistance from electrochemistry and simulation perspectives

The performance of GO and hydroxylated BN in improving the corrosion resistance of a water-borne epoxy coating was comparatively investigated to evaluate the relative excellence of two nanofillers. Electrochemical tests indicated that GO outperformed hydroxylated BN. The corrosion current density was further decreased to 3.48 × 10−6 A/cm2 and polarization resistance was increased to 8.67 × 104 Ω·cm2. The electrochemical reactivity was also most significantly decreased with incorporating GO. Without changing the coating structure, the superior performance of GO was attributed to its exceptional ability to capture water molecules as revealed by simulation results. The mass transfer process of water molecules within coatings was inhibited and the redox reactions during corrosion process were thereby effectively controlled.

Electrochemical CO2 reduction on Single-Atom aluminum catalysts supported on graphene and N-doped Graphene: Mechanistic insights and hydration effects

By means of periodic density functional theory calculations, we have investigated the electrochemical reduction of carbon dioxide (CO2RR) on single-atom aluminum catalysts anchored on graphene substrates (Al-3C-graphene and Al-3N-graphene). The predominant path of CO2RR on Al-3C-gra proceeds via the HCOO* intermediate, with the possible products HCOOH* and CH3OH* tightly controlled at the Al site until the formation of CH4. The potential determining step (PDS) is the conversion of HCOOH* to CH2OOH*, an endergonic process requiring 0.33 eV. The Al site of Al-3N-gra exhibits strong binding with the COOH* and HCOO* intermediates; however, the formation of HCOO* still prevails. The PDS becomes the conversion of HCOO* to H2COO*, with a limiting potential (UL) of –0.22 V, resulting in the formation of an OH* species occupying the Al site. Regardless of whether it is on Al-3C or Al-3N, the water molecules generated during CO2RR will be firmly adsorbed onto the aluminum center. Therefore, we also considered CO2RR on hydrated Al-3C and Al-3N-gra. After three water molecules bind with Al-3C and Al-3N, the former will maintain a (H2O*)3-Al-3C-gra complex, while the latter will release a proton and form a (H2O*)2(OH*)-Al-3N-gra complex, which is highly exothermic. The UL of CO2RR on (H2O*)3-Al-3C-gra is reduced to –0.26 V compared to clean Al-3C-gra, indicating that the adsorption of water effectively regulates the relative Gibbs free energy of the intermediates. The UL of CO2RR on (H2O*)2(OH*)-Al-3N-gra becomes –0.72 V, which is higher than the clean Al-3N-gra counterparts. However, the hydrated Al-3N-gra still maintains a great CO2 capture ability.

Mechanistic Insights into the Removal of Surfactant-Like Contaminants on Mesoporous Polydopamine Nanospheres from Complex Wastewater Matrices.

The detrimental environmental effects of surfactant-like contaminants (SLCs) with distinctive amphiphilic structures have garnered significant attention, particularly since perfluorooctanesulfonate was classified as a persistent organic pollutant. Despite the numerous absorbents developed for SLCs removal, the underlying interaction mechanisms remain speculative and lack experimental validation. To address this research gap, we elucidate the mechanistic insights into the selective removal of SLCs using mesoporous polydopamine nanospheres (MPDA) fabricated via a novel soft-template method. We employed low-field nuclear magnetic resonance to quantitatively characterize the hydrophilicity of the absorbents using water molecules as probes. The results demonstrated that MPDA with uniform mesopores exhibited a remarkable threefold enhancement in SLCs' adsorption capacity compared to conventional polydopamine particles via intraparticle diffusion. We further demonstrated the dominant effects of electrostatic and hydrophobic interactions on the selective removal of SLCs with MPDA by regulating the isoelectric pH value and performing a comparative analysis. The mechanism-inspired SLC-removal strategy achieved an average removal rate of 76.3% from highly contaminated wastewater. Our findings offer new avenues for applying MPDA as an efficient adsorbent and provide innovative and mechanistic insights for targeted SLC removal in complex wastewater matrices.

Construction of nano-cage imprinted sites in MOFs-based membrane for precise identification and separation

Here, ribavirin (RBV) was introduced into metal organic frameworks (MOFs) in this instance to direct the in situ fabrication of appropriate nanocage structures to facilitate the targeted binding of RBV. Well-designed nano-caged RBV imprinted membranes (NCRIMs) have remarkable antifouling capabilities and can selectively separate RBV from wastewater generated by the RBV production process by constructing imprinting sites inside the molecule. Polydopamine (PDA) is rich in hydrophilic groups (hydroxyl and amino groups) that interact with water molecules via hydrogen bonding, thereby generating a hydrate layer on the membrane surface. The synthesized RBV imprinted sites were homogeneously scattered at the interface and inside of the membrane, resulting in a satisfactory selectivity. Notably, methacrylic acid and acrylamide act as functional monomers that synergistically promote the ability to selectively recognise RBV imprinting sites. It was demonstrated that NCRIMs had favourable rebinding selectivity (αRBV/ACV = 3.28, αRBV/AZT = 2.48, αRBV/LAM = 3.72) as well as partial selectivity (βRBV /LAM = 9.48, βRBV/AZT = 8.20, βRBV/ACV = 2.95), indicating the potential of NCRIMs in practical application. What is significant is that the cooperative imprinting and modification methods devised in this study offer directions for the selective isolation of valuable components from complex environments, as well as a reference towards the design of potentially highly resistant membranes.

Enhancing the anodic dissolution uniformity of dendritic-structured refractory high entropy alloys using a split electrolytic cell with a deep eutectic solvent

The attainment of uniform anodic dissolution in dendritic-structured refractory high entropy alloys (RHEAs) during the electropolishing process is essential for their utilization in high-precision components. Nevertheless, the intricate microstructures of these materials impede uniform dissolution, resulting in suboptimal surface quality. In this work, based on a choline chloride-based deep eutectic solvent and suitable polarization parameters selected by linear scanning voltammetry, a split electrolytic cell (SEC) was proposed to alter the traditional integrated electrolytic cell (IEC) to enhance the anodic dissolution uniformity of dendritic-structured RHEAs. A much smoother surface with Ra of 0.233 μm and a smaller height discrepancy of 0.8 μm was obtained, compared to those processed in IEC at the same condition. The non-uniform anodic dissolution was mainly attributed to the cathode-forming (hydroxide ion (OH−), dissolution of tungsten (W) in the dendrite region under the attack by OH−, and the formation of by-product, i.e., the water molecule. The positive impact of SEC on dissolution uniformity could be ascribed to its role in inhibiting OH− from interacting with the anode, as well as to the enhancement of solution acidity on the anode side, which facilitated the dissolution of metal oxides. The suggested reaction pathway was subsequently validated through experiments with controlled water concentration and assessing of electrochemical kinetics. Finally, the effects of SEC under different parameters were demonstrated. This work provides valuable insight into the precise, micro/nanoscale manufacturing and green electrochemical surface finishing of RHEAs in the future.

Structure and properties of homogeneous toughened poly(vinyl alcohol) blended membrane and exploration of application in membrane separation

Polyvinyl alcohol (PVA) has excellent physical and chemical properties; however, its rigidity easily leads to brittleness and breakage during use. Additionally, due to intramolecular hydrogen bonding, the dense structure of the film limits its application. This research used a self-toughening approach by homogeneously blending PVA 0588 and PVA 0499 with different molecular weights to enhance the toughness of PVA and create a porous structure for broader application in membrane separation. Porous PVA membranes were then produced through mechanical stretching. Rheological testing, differential scanning calorimetry, and dynamic thermomechanical analysis confirmed that the blend system is partially compatible. Mechanical characterization revealed that adding PVA 0499 decreased the tensile modulus, strength, and bending modulus of the blended film but increased the elongation at break, reaching a maximum of 179 %. This result indicates that homogeneous blending effectively achieved PVA self-toughening. After this, the PVA blended membrane underwent mechanical stretching. Results showed that the stretched membrane developed a porous structure with a PVA 0588 content of 60 wt%, yielding a pure water flux of 70.3 L m−2 h−1 MPa−1 and a glucan rejection rate of 91.07 %. The molecular weight cut-off test demonstrated that the resulting porous membrane was suitable for water treatment, effectively filtering substances with a molecular weight of ≥70 kDa. The membrane also exhibited notable antifouling properties. The hydrophilicity and high roughness of the porous membrane facilitated the formation of additional hydrogen bonds between the membrane surface and water molecules, thereby reducing direct contact between pollutants and the membrane surface. This study provides preliminary theoretical and experimental insights into enhancing PVA toughness and expanding its applications in membrane separation. Furthermore, homogeneous blending opens new avenues for improving the mechanical performance of polymers.

Technological quality improvement of gluten-free dough and chapatti-making by incorporation of modified oat 1,4-β-D-glucan

The present study aimed to explore the contribution of untreated (UtβG) and modified oat 1,4-β-D-glucan (OzβG) to the quality of gluten-free chapattis at varying concentrations (0, 1.5, 3, and 4.5 % labelled as M0, M1, M2 and M3 for maize chapattis and F0, F1, F2 and F3 for finger millet chapattis, respectively). The functionality of flours was significantly enhanced by the addition of UtβG and OzβG. However, OzβG incorporated flour exhibited a more pronounced influence on both functional and farinographic parameters when compared to flours with UtβG. Further, the hardness of the chapattis decreased with incorporation of OzβG and it was lowest for M2 and F2 i.e. 6.38 N and 5.27 N, respectively due to the formation of more carboxyl and hydroxyl groups, which had more affinity towards water molecules. The sensory analysis indicated that OzβG incorporated M2 and F2chapattis exhibited the highest overall acceptability. Hence, this study provides valuable insights into the utilization of UtβG and OzβG for the formulation of gluten-free chapattis with better dough characteristics and chapatti-making properties.

An Examination of the Transport and Acoustics Properties of B3 Vitamins and Aqueous MgCl2 Salt at Various Temperatures and Concentrations

AbstractForecasting various forms of intermolecular contact and the degree to which the solute and solvent are bonded is highly advantageous when using thermo‐acoustical and volumetric data. Both salts and vitamins are abundant in the human body. A variety of thermo‐acoustical and volumetric properties (viz. velocity [U], density [ρ], adiabatic compressibility [β], surface tension [σ], specific heat ratio [γ], acoustic impedance [Z], relative association [RA], relaxation strength [r], isothermal compressibility [kT], and nonlinearity parameter [B/A]) are investigated in this study. Of the vitamin B3 + H2O and vitamin B3 + H2O + MgCl2 systems have been examined. Through solvation and hydrogen bonding, these characteristics are utilized to describe the interactions between solutes and solvents. Compressibility explains the qualitative intermolecular elastic forces that exist between the molecules of the solvent and the solute. The electrostatic field of ions has formed the basis for discussions on the structural arrangement of molecules in electrolyte solutions. The volumetric and thermoacoustic characteristics exhibit concentration‐dependent changes, suggesting the existence of molecular interactions in both systems. The vitamin B3 molecule shows stronger molecular contact at higher solvent concentrations, although it interacts most molecularly with MgCl2 solvents. This suggests that magnesium molecules are more suited for the attachment of vitamin B3 molecules than are water molecules.

Study on the effect of spatial adsorption orientation on the preferential selection mechanism of dust suppression surfactants

Surfactants are widely used in the field of coal dust control. However, the dust suppression effect of different surfactants varies significantly, and the preferential selection mechanism of dust suppressants for mining is not clear. In this study, the water/surfactant/lignite system was constructed by molecular simulation to investigate the adsorption behavior of surfactants with different structures on the lignite surface at the molecular level. The reasons for the differences in the wettability adsorption of sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), fatty alcohol polyoxyethylene ether-9 (AEO-9), and alkyl polyglycoside (APG1214) on the lignite surface were also investigated based on the quantum chemical calculations and macroscopic experimental analysis. The results showed that the adsorption orientation of surfactant molecules at the solid–liquid interface exerted a pivotal influence on the surface wettability of lignite. According to molecular orbital and electrostatic potential analysis, surfactant molecules with LUMO distributed in the tail chain were more inclined to form a positive adsorption orientation than that concentrated in the polar headgroups; and the stronger the interaction between the polar headgroups and the coal surface with the like charge, the more stable the adsorption of surfactant molecules with the positive arrangement at the interface was. Furthermore, the stronger potential difference between SDS molecules and the hydroxyl-rich structure of the APG1214 molecules are conducive to the formation of hydrogen bonds with water molecules. Wettability experiments showed that the ability of surfactants to improve the wettability of coal dust was positively correlated with the adsorption orientation.

Modulation of textural properties in microwave treated gluten-free quinoa sponge cake by alkaline amino acids

Lysine (Lys) and Arginine (Arg) (0.6%) was added to the quinoa flour to improve the textural quality and physical properties of gluten-free sponge cake treated with different heating methods. The gluten-free sponge cake fortified Lys and Arg increased cell density and surface area fraction, compared to water bath (WB) treatment, with the microwave (MW) treatment further enhancing these effects. Furthermore, MW combined Lys treatment showed the best texture characteristics of sponge cake. The water distribution determined by 1H NMR presented that water molecules are bound by the protein network structure. FTIR spectrum proved MW combined with Lys promoted the transition from disordered structure to ordered structure of protein in quinoa sponge cake, which enhanced the expansion of protein molecules and the exposure of hydrophobic regions, thus promoting protein aggregation. SDS-PAGE revealed when alkaline amino acids were present, they can regulate the ordered aggregation of protein molecules under MW alternating electric field, leading to enhanced intermolecular interactions. Finally, microstructure evaluations by SEM demonstrated MW combined with alkaline amino acids formed a stable three-dimensional gel network structure, thus improving the quality of gluten-free quinoa sponge cake. Therefore, the study findings pointed to the feasibility of using MW to improve the physical and textual quality of quinoa gluten-free food.

Unveiling the dissolution mechanism of calcium ions from CSH substrates in Na2SO4 solution: Effects of Ca/Si ratio

The decalcification behavior of calcium silicate hydrate (CSH) under sulfate attack poses a critical challenge to the long-term durability of cement-based infrastructure, yet understanding its underlying microscopic mechanisms remains elusive. This study employs molecular dynamics to compare the differences in calcium ion dissolution capability of CSH substrates with varying Ca/Si ratios under sulfate solution exposure. The results show that the dissolution amount and dissolution efficiency of Ca are positively correlated with Ca/Si, and the root cause depends on the basic structure of CSH. With the increase of Ca/Si, the electronegativity of CSH decreases, and the adsorption capacity and stability of cations weaken. Meanwhile, Ca ions are less limited by the silicate chain coordination, water molecules are more likely to invade the substrate interior and replace the Ca ions. This research aims to provide a molecular basis for cement production and durability applications in marine engineering.

A novel polysulfone ultrafiltration membrane constructed with the sandwich-like structure SGO-ZnO for ultra-easy water transport and enhanced anti-fouling

Fouling formation on membrane surfaces limits membrane-based separation performance in industrial activities such as wastewater recycling and desalination. Designing and preparing emerging materials capable of improving the balance between permeability and rejection remains a great challenge. A sandwich-like composite with loose and flat interlayers was produced by combining rigid zinc oxide (ZnO) nanoparticles with easily stackable, folded sulfonated graphene (SGO) and subsequently non-solvent-induced phase separation (NIPs) was employed to produce novel PSF ultrafiltration (UF) membranes with varying amounts of nanofiller of SGO-ZnO. The successful anchoring of ZnO on SGO was confirmed by FTIR, XRD, Raman spectroscopy and TGA. The produced membranes have been investigated using contact angle (CA), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The incorporation of ZnO suppressed the stacking and wrinkling of SGO, which increased the vertical interlayer paths and lateral bending paths. As a result, water molecules could freely pass through the extended channels of SGO, and with only 0.2 wt% of nanoparticles doped, the pure water flux was increased f from 229.2 L m−2h−1 to 601 L m−2h−1. Negatively charged impurities were selectively repelled due to electrostatic interactions with −SO3H, which resulted in the removal of BSA remaining above 98 %. In addition, the separation performance of the humic acid (HA)-simulated water sample, a common contaminant, was investigated using the designed modified membranes. The greatest HA rejection (98.33 %) was shown by the UF membrane. All these findings suggest that the addition of sandwich-like SGO-ZnO successfully overcomes the “trade-off effect” between permeability and selectivity in PSF membranes.

Thermal performance of a novel composite phase change material for solar-assisted air source heat pump packed bed thermal energy storage application

The thermal properties of the heat storage medium in the solar-assisted air source heat pump (SAASHP) systems must be aligned with the system’s heat generation temperature while satisfying the heat demand. In this study, a novel composite phase change material (CPCM) for efficient heat storage in SAASHP systems was developed. Our investigation revealed that the incorporation of 8 wt% KNO3, 1.5 wt% thickener, and 1.0 wt% Al2O3 nanoparticles into sodium acetate trihydrate resulted in the manifestation of desirable properties suitable for SAASHP systems. The compound exhibited a suitable melting point of 48.66 °C, high latent heat of 235.97 kJ/kg, low supercooling degree of 2.25 °C, and good thermal conductivity of 0.905 W/(m·K). Furthermore, the novel CPCM demonstrated exceptional thermal stability, with only an 8.64 % loss of latent heat after undergoing 200 cycles, while maintaining a supercooling degree within a range of 6 °C for each cycle. Moreover, molecular dynamics simulation results further indicated that the presence of KNO3 weakened the interaction between CH3COONa molecules and water molecules, leading to a reduction of the melting point. Additionally, numerical analysis revealed that the total heat storage capacity and exergy storage capacity of the packed bed thermal energy storage (PBTES) system filled with the novel CPCM are 358.8 MJ and 25.1 MJ, respectively. With an increase in the heating power of the SAASHP system from 10 kW to 30 kW, the cycle heat storage time of the PBTES system can decrease by 38.8 %, while an increase in the flow rate from 2 m3/h to 6 m3/h can reduce the time by 26.3 %. These findings have significant implications for the selection and composition design of thermal storage materials in SAASHP systems.

Low-field MRI study of the 1H distribution and migration in porous sediments during natural gas conversion from methane hydrate

Gas hydrates, crystalline compounds formed from water and guest molecules like methane, are gaining attention as a promising clean energy source. While research has extensively focused on the extraction and transport of natural gas hydrates from offshore marine sediments, the dynamic processes in the porous sediments remain under explored. This study employs low-field Magnetic Resonance Imaging (MRI) to investigate the in-situ formation and dissociation of methane hydrate within a partially saturated stack of glass beads. By integrating advanced MRI techniques, including 1D dhk SPRITE, bulk T1 distribution, and 2D spatial T2 imaging, this research provides a comprehensive analysis of fluid distribution and migration during phase transitions in the porous sediments. Three key findings emerged from the study. First, SE-SPI measurements successfully quantified hydrate and residual water saturation, aligning with previous X-ray CT and high-field MRI studies and validating low-field MRI for hydrate research. Secondly, this study introduced a volumetric approach to T1 and T2 measurements, distinguishing between free and bound water, with characteristic relaxation times for each, confirming the technique’s capability to differentiate types of residual water. Finally, spatially resolved T2 relaxation time distributions revealed vertical fluid migration within the pore spaces, identifying an equilibrium zone where inflow and outflow rates were balanced. Overall, this study underscores the effectiveness of low-field MRI as a noninvasive tool for analyzing hydrate-bearing sediments. The findings lay the groundwork for further exploration of hydrate in porous sediments, enhancing our understanding of gas production dynamics in hydrate-rich environments.

Conformations of α-Cyclodextrin and Its Role on the Stability of Inclusion Complexes in Aqueous Solution

α-Cyclodextrin (αCD), a cyclic carbohydrate polymer, presents a wealth of opportunities for drug delivery and various industrial applications. Its high affinity and selectivity in encapsulating target molecules have been well-documented. However, the influence of αCD's conformational variations on its encapsulation capacity remains a promising area for further exploration. This study explores the conformational dynamics of αCD and its relationship with the formation of inclusion complexes (ICs) in aqueous solutions, focusing on understanding the forces driving these dynamics and the formation of stable ICs. Classical molecular dynamics (CMD) demonstrate that αCD solvated in water can adopt two conformations: a truncated cone shape with a suitable cavity for encapsulation and a distorted cone shape with a collapsed cavity. The predominant conformation observed in the CMD trajectory of pristine αCD is the distorted cone. However, under complexation conditions with aliphatic molecules, the guest molecule's size dictates the ICs' stability, forcing αCD to maintain the truncated conformation. Quantum chemistry methods and electron density analyses (quantum theory of atoms in molecules and non-covalent interactions index) support CMD observations by characterizing and quantifying non-covalent interactions. Findings indicate that the shift from the truncated to the distorted cone conformation in αCD is primarily driven by intramolecular non-covalent interactions and the reconfiguration of water molecules surrounding αCD. The ICs' analysis displays a significant correlation between the size of the aliphatic chain and the intensity of intermolecular interactions. The strength of these interactions can effectively disrupt the αCD intramolecular non-covalent interactions that lead to a conformational change and, consequently, the loss of the inclusion complex. In conclusion, although αCD's conformational change can affect encapsulation, guest molecules can manipulate the conformational preference. The systematic analysis of non-covalent interactions offers a way to characterize and quantify these forces, enhancing our ability to understand and predict the stability of inclusion complexes.

High-Performance Broadband Photodetectors Combining Perovskite and Organic Bulk Heterojunction Bifunctional Layers

Perovskite can be used to prepare high-performance photodetectors due to its excellent optical properties. However, the detection range of perovskite photodetectors is mostly limited to the visible light range, restricting their further development and application. In recent years, combining perovskite with organic bulk heterojunctions to prepare photodetectors with broadband detection capability has proven to be an effective strategy. Through this approach, the response spectrum of the photodetector can be flexibly regulated, and organic compounds can improve the perovskite film quality by passivating defects and inhibit the penetration of water molecules in the air, thereby improving the device performance and stability. In this work, we propose and demonstrate the feasibility of combining MAPbI3 perovskite with PTB7-Th:COTIC-4F to prepare high-performance photodetectors with wide spectral response characteristics. With the assistance of an organic bulk heterojunction, the defects of perovskite crystals are effectively passivated, and the detection spectrum of the device is successfully extended to about 1100 nm. As a result, the responsivity achieved is 0.58 A/W, 1.19 A/W, and 1.41 A/W under laser illumination of 532 nm, 808 nm, and 980 nm, with the power density of 5 μW/cm2 at the bias voltage of −0.5 V, respectively, which is one of the best performances among vertical device structures of this type. Moreover, the stability of the final hybrid film has been greatly improved. This work provides a new approach to the preparation of high-performance and broadband perovskite photodetectors.