Large Dipole Moment Research Articles

Molecular Engineering of Perylene Diimide Polymers with a Robust Built‐in Electric Field for Enhanced Solar‐Driven Water Splitting

AbstractThe built‐in electric field of the polymer semiconductors could be regulated by the dipole moment of its building blocks, thereby promoting the separation of photogenerated carriers and achieving efficient solar‐driven water splitting. Herein, three perylene diimide (PDI) polymers, namely oPDI, mPDI and pPDI, are synthesized with different phenylenediamine linkers. Notably, the energy level structure, light‐harvesting efficiency, and photogenerated carrier separation and migration of polymers are regulated by the orientation of PDI unit. Among them, oPDI enables a large dipole moment and robust built‐in electric field, resulting in enhanced solar‐driven water splitting performance. Under simulated sunlight irradiation, oPDI exhibits the highest photocurrent of 115.1 μA cm−2 for photoelectrochemical oxygen evolution, which is 11.5 times that of mPDI, 26.8 times that of pPDI and 104.6 times that of its counterparts PDI monomer at the same conditions. This work provides a strategy for designing polymers by regulating the orientation of structural units to construct efficient solar energy conversion systems.

Nano-second life time decay and Z-scan measurement: A tool to investigate the relevance of excited state dynamics with non-linear optical parameters in cis substituted Wells-Dawson POM-Porphyrin hybrids

Materials possessing non-linear optical NLO responses have gained considerable attention in the field of photonics because they have the potential to produce new frequencies when they interact with intense light by means of non-linear interactions. Synthesizing NLO materials based on porphyrin covalently bonded with polyoxometalates (POMs) is complicated and rigorous, requiring special techniques in order to get pure compounds with a higher yield. Here, we study the third-order NLO parameters along with the fluorescence lifetime decay values in a nanosecond(ns) time span for WDPOMCis2PyP and WDPOMCis2PhP (bearing the Wells-Dawson POM at the cis position) and their porphyrin precursors Cis2PyPTris and Cis2PhPTris, respectively. A comparison of third-order NLO characteristics with fluorescence lifetime decay data indicates that an increase in NLO properties has been observed with shorter lifetime decay values and vice versa. From the results, it is clear that WDPOMCis2PhP showed better third-order NLO (χ3 = 2.60 × 10−10 esu and β = 8.26 × 10−11 cm/W) than WDPOMCis2PyP (χ3 = 2.25 × 10−10 esu and β = 5.60 × 10−11 cm/W), which is supported by lifetime decay values. The lifetime decay value for WDPOMCis2PhP (τ1 = 2.77 ns) is shorter than WDPOMCis2PyP (τ1 = 6.02 ns). In addition to the factors mentioned based on substituent impact and molecular geometry, the WDPOMCis2PyP has a larger dipole moment than other POM-based porphyrin hybrids, which accounts for the improved third-order NLO response. Minor energy variance among singlet, triplet excited states, and charge-separated states favors quicker intersystem crossing of the WDPOMCis2PyP and WDPOMCis2PhP, which boosts NLO responses, and this actually makes WDPOMCis2PyP and WDPOMCis2PhP better than their corresponding POMs free porphyrins Cis2PyPTris and Cis2PhPTris, leading to their uses in optical devices.

Solvatochromic shifts and solvent effects on the electronic and transport behaviour of 1-Chloro Adamantane

Solvent influence on the photophysical and electronic properties of 1-Chloro Adamantane (CAD) are investigated using experimental and computational methods. Measured UV–vis absorption of CAD in various solvents exhibits substantial solvatochromatic shifts with respect to the solvent polarity. As a result of this, optical absorption of CAD undergoes the bathochromic shifts in the nonpolar solvents and hypsochromic shifts in the polar solvents with respect to polarity. Theoretical computations of EOM-CCSD and CIS quantum chemical methods calculated by means of SMD solvation model demonstrate the solvent influence on the electronic structure of CAD which are in good agreement with the experimental results. Computed results show prominent solvation effect on Lewis and non-Lewis occupancies. Large excited state dipole moment of the CAD in various solvation suggests excited states are more polarized than the ground state. In addition to this, molecular polarizabilities and energies of HOMO and LUMO show dominant solvent effects on the chemical reactivity of the CAD upon solvation. This solvent specific behaviour of CAD finds applications in optical filters with its significant hydrophobic nature.

Facilitating charge separation and migration of conjugated microporous polymers via skeleton isomerism engineering for photocatalytic reduction of uranium (VI)

Photoreduction of highly toxic and high-mobility UVI into insoluble UIV via conjugated microporous polymers (CMPs) is an effective way to extract uranium from highly acidic wastewater. Nevertheless, undesirable charge separation and migration, as well as rapid reverse charge recombination resulted in unsatisfactory photocatalytic activity of most CMPs. Herein, a pair of D-A CMPs for uranium photocatalytic reduction was developed by modulating skeleton isomerism through isomeric building blocks, named PQ-TPM (with phenanthrenequinone skeleton) and AQ-TPM (with anthraquinone skeleton). Interestingly, compared with anthraquinone skeleton CMP, phenanthrenequinone skeleton CMP can inhibit reverse charge recombination while promoting charge separation and migration due to its stronger built-in electric field and larger dipole moment. Therefore, PQ-TPM achieves an ultra-high photocatalytic UVI removal efficiency of 80.0 % within 180 min visible-light irradiation even under strongly acidic conditions (pH = 2), which was superior to AQ-TPM (30.0 %) and most reported CMPs. This study provides an unconventional concept and an emerging strategy for exploring outstanding CMPs photocatalysts for efficient processing of radionuclides.

An Azulene-Based Crystalline Porous Covalent Organic Framework for Efficient Photothermal Conversion.

The designed synthesis of a crystalline azulene-based covalent organic framework (COF-Azu-TP) is presented and its photothermal property is investigated. Azulene, a distinctive 5-7 fused ring non-benzenoid aromatic compound with a large intramolecular dipole moment and unique photophysical characteristics, is introduced as the key feature in COF-Azu-TP. The incorporation of azulene moiety imparts COF-Azu-TP with broad-spectrum light absorption capability and interlayer dipole interactions, which makes COF-Azu-TP a highly efficient photothermal conversion material. Its polyurethane (PU) composite exhibits a solar-to-vapor conversion efficiency (97.2%) and displays a water evaporation rate (1.43kg m-2 h-1) under one sun irradiation, even at a very low dosage of COF-Azu-TP (2.2wt%). Furthermore, COF-Azu-TP is utilized as a filler in a polylactic acid (PLA)/polycaprolactone (PCL) composited shape memory material, enabling rapid shape recovery under laser stimulation. A comparison study with a naphthalene-based COF isomer further emphasizes the crucial role of azulene in enhancing photothermal conversion efficiency. This study demonstrates the significance of incorporating specific building blocks into COFs for the development of functional porous materials with enhanced properties, paving the way for future applications in diverse fields.

Electromagnetically Induced Transparency Spectra of 6Li Rydberg Atoms

Rydberg atoms possess highly excited valence electrons that are far away from atomic cations. Compared with ground states, Rydberg states are excited states with a high principal quantum number n that exhibit large electric dipole moments and have a variety of applications in quantum information processing. In this communication, we report the measurement of the 6Li Rydberg excitation spectrum by ladder-type electromagnetically induced transparency (EIT) in a vapor cell. The 2p→ns/nd EIT spectra were recorded by sweeping the frequency of an ultraviolet Rydberg pumping laser while keeping the probing laser resonant to the 2s→2p transition. All lasers were locked on an ultrastable optical Fabry-Pérot cavity and measured by an optical frequency comb. Our results provide valuable information to precisely determine quantum defects and enable novel experiments with Rydberg-dressed ultracold Fermi gases.

Macrocyclization-induce emission enhancement characteristics of benzothiadiazole-based macrocycles: A theoretical study

We present a comprehensive investigation into the molecular structures in the ground state and the first singlet excited state, intramolecular and intermolecular interactions, as well as the emission properties of monomers, dimers and macrocycles using density functional theory and time-dependent density functional theory. Our study aims to unveil the macrocyclization-induce emission enhancement principle for benzothiadiazole-based macrocycles. Compared with the typical π-π stacking of monomers, macrocycles exhibit the tighter stacking arrangement due to the presence of strong intramolecular and intermolecular hydrogen bond interactions and the rigid triangular geometry of macrocycle, which is conducive to the enhancement of emissions efficiency. The calculated oscillator strength of macrocycles in the first excited state is much higher than that of dimers composed of two monomers. Meanwhile, the large transition electric dipole moment is beneficial for enhancing the emission efficiency. Additionally, our study reveals an emission wavelength red-shift for macrocycles after “CH”/N substitution in the acceptor moiety, and the transition mode from LUMO to HOMO can be mainly attributed to intramolecular charge transition characters from acceptor to donor fragments. Our theoretical study might provide valuable insights for the design of innovative luminescent macrocycles with high emission efficiency.

Enhancing photovoltaic materials: DFT insights into structural modification of benzo [1, 2-b: 4, 5-b1]dithiophene unit (BDT)-based molecule

Four small molecule (DRTTBDT-A1 to DRTTBDT-A4) based on Benzodithiophene were studied for their optoelectronic properties and compared to the reference molecule (DRTTBDT-R) as potential donors in organic solar cells. The designed molecules feature electron-withdrawing moieties attached to both terminals of the reference molecule. Computational investigations using density functional theory indicated that DRTTBDT-A1 displayed the most intriguing characteristics in dichloromethane solvent, with a small energy gap of 3.84 eV, a high λmax at 519 nm, and a large dipole moment of 5.92 D. These features suggest superior miscibility and potential for high performance in OSCs. The newly engineered molecules also exhibited higher open-circuit voltage and power conversion efficiency compared to the reference, indicating enhanced operational efficiency. PCE values ranging from 27.90 to 31.71 were observed, surpassing the reference molecule's PCE of 27.49. These findings demonstrate the potential of structural modifications in designing efficient photovoltaic materials for solar energy applications.

Dielectric Regulation for Efficient Top-Emission Perovskite Light-Emitting Diodes with Suppressed Efficiency Roll-off.

Perovskite light-emitting diodes (PeLEDs) have shown incalculable application potential in the fields of next-generation displays and light communication owing to the rapidly increased external quantum efficiencies (EQEs). However, most PeLEDs obtain a maximum EQE at small current density (J) region and suffer from severe efficiency roll-off in different extents. Herein, it is demonstrated that the dopant with large dipole moment like KBF4 facilitates the effective dielectric regulation of perovskite emissive layer. The increased dielectric constant lowers the exciton binding energy and suppresses the Auger recombination of the 2D/3D segregated perovskite structure, which improves the photoluminescence quantum yield remarkably at an excitation intensity up to 103mWcm-2. Accordingly, the top-emission PeLED that delivers a high maximum EQE above 20% is fabricated and can retain EQE>10% at an extremely high J of 708mAcm-2. These results represent one of the most efficient top-emission PeLEDs with ultra-low efficiency roll-off, which provide a viable methodology for tuning the dielectric response of perovskite films for improved high radiance performance of perovskite electroluminescence devices.

Zwitterionic liquid-based gel electrolyte for high performance lithium metal battery at low temperatures

Gel electrolyte (GE) gains intensive attentions for lithium metal battery, especially those targeting to use at low temperatures. The liquid medium, as the core component, of most gel electrolytes (GEs) is organic liquid or ionic liquid, always suffering from serious safety issue and low transference number (t+). The low t + aggravates concentration polarization and thus leads to the increase of overpotential and undesirable side reactions. Herein, zwitterionic liquid (ZIL) with high stability and safety is prepared by mixing zwitterion (ZI) and lithium salt. The ZIL is then encapsulated into a SiO2 matrix to fabricate novel gel electrolyte (SiGE-ZIL). The low freezing point and strong mobility of ZIL confer SiGE-ZIL a high conductivity of 3.36 × 10−4 S cm−1 at −40 °C. Importantly, the large dipole moment of ZI effectively accelerates the dissociation of lithium salt, permitting a high t+ of 0.553 at −40 °C, which is 2.3 times of that of the analogous ionic liquid. The assembled LiFePO4/Li battery exhibits an excellent cycling stability with a capacity of 91.6 mAh g−1 at 600th cycle at 0.5C and 0 °C. Especially at −20 °C, the capacity can reach 67.1 mAh g−1 at 600th cycle under 0.5C, surpassing most of GE-based batteries.

Deep-Ultraviolet Transparent Mixed Metal Sulfamates with Enhanced Nonlinear Optical Properties and Birefringence.

Enhancing anisotropy through the controlled arrangement of anionic groups is essential for improving the nonlinear optical (NLO) performance of non-π-conjugated NLO materials. In this study, we present the successful synthesis of the first examples of mixed alkali metal-alkaline earth metal sulfamate materials, including noncentrosymmetric Cs2 Mg(NH2 SO3 )4 ⋅ 4H2 O (1), as well as centrosymmetric K2 Ca(NH2 SO3 )4 (2) and Rb2 Ca(NH2 SO3 )4 (3). All three compounds feature promising deep ultraviolet cut-off edges, notably 1 with a cut-off edge below 180 nm. The synergy of Cs+ and Mg2+ cations in 1 facilitated the successful alignment of polar [NH2 SO3 ] tetrahedra in a uniform orientation. Remarkably, 1 stands as the sole instance among reported sulfamate compounds with a co-parallel anionic arrangement, yielding a very large dipole moment compared to other non-π-conjugated NLO materials. Moreover, the substantial dipole moment of 1 yields an enhanced second harmonic generation response, approximately 2.3 times that of KH2 PO4 , and a large birefringence of 0.054 at 546.1 nm. The approach of regulating the arrangement of anionic groups using aliovalent cations holds promise for advancing the exploration of non-π-conjugated NLO materials.

Deep‐Ultraviolet Transparent Mixed Metal Sulfamates with Enhanced Nonlinear Optical Properties and Birefringence

AbstractEnhancing anisotropy through the controlled arrangement of anionic groups is essential for improving the nonlinear optical (NLO) performance of non‐π‐conjugated NLO materials. In this study, we present the successful synthesis of the first examples of mixed alkali metal‐alkaline earth metal sulfamate materials, including noncentrosymmetric Cs2Mg(NH2SO3)4 ⋅ 4H2O (1), as well as centrosymmetric K2Ca(NH2SO3)4 (2) and Rb2Ca(NH2SO3)4 (3). All three compounds feature promising deep ultraviolet cut‐off edges, notably 1 with a cut‐off edge below 180 nm. The synergy of Cs+ and Mg2+ cations in 1 facilitated the successful alignment of polar [NH2SO3] tetrahedra in a uniform orientation. Remarkably, 1 stands as the sole instance among reported sulfamate compounds with a co‐parallel anionic arrangement, yielding a very large dipole moment compared to other non‐π‐conjugated NLO materials. Moreover, the substantial dipole moment of 1 yields an enhanced second harmonic generation response, approximately 2.3 times that of KH2PO4, and a large birefringence of 0.054 at 546.1 nm. The approach of regulating the arrangement of anionic groups using aliovalent cations holds promise for advancing the exploration of non‐π‐conjugated NLO materials.

Isomeric Dual-Pore Two-Dimensional Covalent Organic Frameworks.

Two-dimensional (2D) covalent organic frameworks (COFs) with hierarchical porosity have been increasingly recognized as promising materials in various fields. Besides, the 2D COFs with kagome (kgm) topology can exhibit unique optoelectronic features and have extensive applications. However, rational synthesis of the COFs with kgm topology remains challenging because of competition with a square-lattice topology. Herein, we report two isomeric dual-pore 2D COFs with kgm topology using a novel geometric strategy to reduce the symmetry of their building blocks, which are four-armed naphthalene-based and azulene-based isomeric monomers. Owing to the large dipole moment of azulene, as-prepared azulene-based COF (COF-Az) possesses a considerably narrow band gap of down to 1.37 eV, which is much narrower than the naphthalene-based 2D COF (COF-Nap: 2.28 eV) and is the lowest band gap among reported imine-linked dual-pore 2D COFs. Moreover, COF-Az was used as electrode material in a gas sensor and exhibits high selectivity for NO2, including a high response rate (58.7%) to NO2 (10 ppm), fast recovery (72 s), up to 10 weeks of stability, and resistance to 80% relative humidity, which are superior to those of reported COF-based NO2 gas sensors. The calculation and in situ experimental results indicate that the large dipole moment of azulene boosts the sensitivity of the imine linkages. The usage of isomeric building blocks not only enables the synthesis of 2D COFs with isometric kgm topology but also provides an azulene-based 2D platform for studying the structure-property correlations of COFs.

A computational insight into enhancement of photovoltaic properties of non-fullerene acceptors by end-group modulations in the structural framework of INPIC molecule

Improving the open circuit voltage is a major challenge for enhancing the overall efficiency of organic solar cells. Current work has concentrated on improving open-circuit voltage by designing new molecular frameworks from an INPIC molecule having a conjugated fused core. We modulated the structure by changing the terminal groups of the reference molecule (INPIC) with seven strong electron-withdrawing units. We investigated various optoelectronic attributes, charge transfer, and photovoltaic and geometrical parameters by compiling the B3LYP/6-31G(d,p) functional of the DFT approach. The optical absorption for modulated molecules ranges from 748.51 nm to 845.96 nm while showing higher oscillation strength than INPIC. At the same time, their impressive charge transport is attributed to their smaller excitation and exciton binding energy, higher electron/hole mobility, narrower band gap, and a more than 99 % intramolecular charge transfer. The larger dipole moments help in the dense interaction of acceptors with employed donor J61 which, in turn, improves charge transfer at the donor-acceptor interface. One of the triumphs that are difficult to get in organic molecules is success in achieving a higher open circuit voltage (VOC). Our conceptualized molecular frameworks of acceptors are featured with a notable VOC improvement in the range of 1.84–2.05 eV. Thus, the results of the current investigation pave the root for architecting the acceptor molecules with impressive optoelectrical properties that may be capable of providing high photovoltaic output. Thus these acceptors can be utilized for the development of advanced organic solar cells in future.

Learning from the 4-(dimethylamino)benzonitrile twist: Two-parameter range-separated local hybrid functional with high accuracy for triplet and charge-transfer excitations.

The recent ωLH22t range-separated local hybrid (RSLH) is shown to provide outstanding accuracy for the notorious benchmark problem of the two lowest excited-state potential energy curves for the amino group twist in 4-(dimethylamino)benzonitrile (DMABN). However, the design of ωLH22t as a general-purpose functional resulted in less convincing performance for triplet excitations, which is an important advantage of previous LHs. Furthermore, ωLH22t uses 8 empirical parameters to achieve broad accuracy. In this work, the RSLH ωLH23ct-sir is constructed with minimal empiricism by optimizing its local mixing function prefactor and range-separation parameter for only 8 excitation energies. ωLH23ct-sir maintains the excellent performance of ωLH22t for the DMABN twist and charge-transfer benchmarks but significantly improves the errors for triplet excitation energies (0.17 vs 0.24eV). Additional test calculations for the AE6BH6 thermochemistry test set and large dipole moment and static polarizability test sets confirm that the focus on excitation energies in the optimization of ωLH23ct-sir has not caused any dramatic errors for ground-state properties. Although ωLH23ct-sir cannot replace ωLH22t as a general-purpose functional, it is preferable for problems requiring a universally good description of localized and charge-transfer excitations of both singlet and triplet multiplicity. Current limitations on the application of ωLH23ct-sir and other RSLHs to the study of singlet-triplet gaps of emitters for thermally activated delayed fluorescence are discussed. This work also includes the first systematic analysis of the influence of the local mixing function prefactor and the range-separation parameter in an RSLH on different types of excitations.

Donor-acceptor functionalized coumarin derivatives: Synthesis, fluorescence modulation, interaction with human serum albumin and acetylcholinesterase inhibition activity

A coumarin compound 7-diethylaminocoumarin (DEAC) and its substituted derivative coumarin-6-CF3 (CCF3) were synthesized, characterized and their photophysical behavior have been investigated by steady state and time resolved fluorescence spectroscopy. Both the investigated systems show appreciable modulation in photophysical properties depending on the nature of the solvent medium and in presence of sequestering agents like cyclodextrin nanocavities and/or human serum albumin (HSA). Quantitative estimation of different solvent parameters responsible for the modulated spectral features were done from multiple linear regression analysis of the experimental data based on Kamlet-Taft and Catalán formalisms. Significant modulation in fluorescence quantum yield in polar-protic medium and/or highly viscous glycerol solution for CCF3 in comparison with the model compound DEAC was due to donor–acceptor functionalization in the former. This additional excited state charge transfer possibility led to very large excited state dipole moment change in CCF3 and resulted almost ∼ 90 nm solvent dependent fluorescence peak shift. Multi-pronged experimental results in conjunction with molecular docking calculation revealed moderate binding affinity of the investigated systems towards HSA. Additionally, the coumarin derivatives were evaluated for its anticholinergic activity using in-vitro acetylcholinesterase enzymatic assay. The results demonstrated a significant inhibition of cholinergic activity, particularly for donor–acceptor functionalized CCF3, highlighting the potential therapeutic application of it. The study provides important insights into the molecular interactions and pharmacological properties of these promising coumarin derivatives, which could serve as a basis for the development of new drug candidates targeting cholinergic pathways.

The unusual 3D distribution of NaCl around the asymptotic giant branch star IK Tau

Context. Sodium chloride (NaCl) is a diatomic molecule with a large dipole moment, which allows for its detection even at relatively low abundances. It has been detected towards several evolved stars, including the asymptotic giant branch (AGB) star IK Tau, around which it is distributed in several clumps that lie off-centre from the star. Aims. We aim to study the 3D distribution of NaCl around the AGB star IK Tau and determine the abundance of NaCl relative to H2 for each of the clumps. Methods. First, a new value for the maximum expansion velocity was determined. The observed ALMA channel maps were then de-projected to create a 3D model of the distribution of NaCl. This model was then used as input for the radiative transfer modelling code Magritte. We determined the NaCl abundances of each of the clumps by comparing the observations with the results of the Magritte simulations. Results. We derive an updated value for the maximum expansion velocity of IK Tau: υexp = 28.4 ± 1.7 km s−1. A spiral-like shape can be discerned in our 3D distribution model of NaCl. This spiral lies more or less in the plane of the sky, with the distribution flatter in the line-of-sight direction than in the plane of the sky. We find clump abundances of between 9 × 10−9 and 5 × 10−8 relative to H2; the relative abundance is typically lower for clumps closer to the star. Conclusions. This is the first time de-projection has been used to understand the 3D environment of molecular emission around an AGB star and to calculate the fractional abundance of NaCl in clumps surrounding the star.

Exciton-induced electric dipole moment in organic ferromagnets

Based on an Anderson-like model including electron–lattice interaction and electron–electron (e–e) interactions, charge and spin properties of excitons in quasi-one-dimensional organic ferromagnets with spin radicals are investigated. The results demonstrate the appearance of an unusually large electric dipole moment in the magnetic molecule upon the formation of the exciton. The sign of the dipole moment depends on the spin of the excited electron relative to the magnetization of the spin radicals. The underlying mechanism is analysed based on the different charge distribution and lattice distortion in the two excitation modes with opposite spin. The origin is attributed to the preferred occupation on different domain walls of the exciton distortion for different spin-resolved excitonic levels. The experimental realization of the large dipole moment is discussed. Although the realization of a large dipole moment is impeded by the superposition state formed due to the degeneracy of two excitation modes, we propose an achievable route to break the symmetry and create controllable electric polarization by optical illumination. The dipole moment is robust even if the long-range e–e interaction is included. The effects of the system parameters, including the electron hopping between the main chain and the radicals and the e–e interaction, on the magnitude of the dipole moment are also discussed. This work indicates a novel way to realize organic multiferroic materials with controllable polarization, which can be induced by photon excitation.

Borophene as an carrier for mercaptopurine drug: electronic study via density-functional theory computations.

This paper studied MP-B36 interactions through DFT. MP molecules were observed to have a substantial tendency to be adsorbed through their N heads onto B36 at its edge, based on large adsorption energy values. The B atoms at the edges of B36 nanosheets showed higher reactivity than the internal B atoms toward MP. The electronic properties changed upon MP adsorption. The MP-B36 configurations of the highest stability underwent an energy gap reduction of 11-47%. Natural bond orbital (NBO) analysis and molecular electrostatic potential (MEP) analysis were used to evaluate the MP-B36 interaction. The configurations were subjected to geometric optimization at the TPSSH/6-31 + G(d) level of theory, at which frequency analysis was carried out to evaluate the stationary points. These configurations were neutral (Q = 0). The electronic properties of MP dramatically changed upon its interaction with B36 nanosheets. The stable configurations underwent an energy gap reduction, suggesting a chemical signal. The MP molecules were observed to be effectively adsorbed onto the B36 edge within aqueous phases. The MP-B36 configurations were estimated to have relatively large dipole moments. This demonstrated that MP-B36 systems were soluble and dispersed within solar media (e.g., water). It was concluded that B36 nanosheets could serve as efficient MP carriers in nanomedical drug delivery applications.

Adsorption films based on indazole derivatives for application to protect Cu in sulfuric acid: Experimental and theoretical approaches

BackgroundFinding more cost-effective, low-toxicity corrosion inhibitors to reduce copper corrosion in acidic environments is critical. MethodsThe anti-corrosion abilities and mechanisms of 5‑bromo-1H-indazole (5-BIA) and 7‑bromo-1H-indazole (7-BIA) on Cu in 0.5 M H2SO4 environment have been explored by a way of combining both experimental and theoretical approaches. Significant findingsElectrochemical experiments have shown that both 5-BIA and 7-BIA are capable of acting as highly effective corrosion inhibitors for copper, and 5-BIA has a more prominent protective ability than 7-BIA, which has also been proved by weight loss experiments, SEM and AFM. The corrosion inhibition efficiency (ηE) of 1.5 mM 5-BIA and 1.5 mM 7-BIA is as high as 97.1 % and 94.0 %, respectively. The adsorption of 5-BIA and 7-BIA on the metal surfaces conforms to the Langmuir monolayer adsorption model, and both chemosorption and physical adsorption exist. In addition, quantum chemical calculations reveal that 5-BIA has smaller energy gap (ΔE) and hardness (η) values, and larger dipole moment (μ), absolute electronegativity (χ), and chemical softness (σ) values, thus exhibiting better anti-corrosion ability. Molecular dynamics simulations display that both 5-BIA and 7-BIA can be adsorbed on the Cu (111) surface in an approximately parallel approach, which is conducive to achieving 5-BIA and 7-BIA to hinder the process of copper corrosion as much as possible.