Charge Transfer Capability Research Articles

Construction of Co9S8@NiCo2S4 core–shell hetero-nanostructure with synergistic effect of abundant mesopores and multi-metallic elements for novel high-performance flexible hybrid supercapacitors

Flexible portable supercapacitor devices have gained increasing attention in the field of energy storage in recent years. However, challenges remain in the selection of applicable flexible materials and/or the preparation of materials. Through our research, we have effectively constructed a flexible CS@NCS/CC core–shell hetero-nanostructured cathode material by anchoring Co9S8 (CS) nanopins on a flexible carbon cloth (CC) substrate firstly, and then wrapping NiCo2S4 (NCS) nanosheets on the outer surface of CS nanopins. In this process, we have improved the traditional two-step method of preparing NCS nanosheets into a one-step method, which has greatly improved the efficiency of the material preparation. The prepared CS@NCS/CC material has abundant mesopores, stable core–shell heterostructures and multiple valence states of metal ions, which enable the CS@NCS/CC electrode material to have strong electrochemical reaction kinetics and excellent cycling stability. Additionally, the CC as the flexible substrate improves the charge transfer capability of the transition metal composite. Benefiting from the synergistic effect of these favorable factors, the electrode material exhibits a high Cs value of 2020.6F g−1, which maintains 89.8% after 10,000 constant current charges and discharges. It is worth noting that the CS@NCS/CC can be folded and twisted at multiple angles, which proves that it can be used in wearable applications. The flexible hybrid supercapacitor CS@NCS/CC//AC/CC displays terrific energy density (58 Wh kg−1, at 800 W kg−1) with the synergistic effect of pseudocapacitance and electrical double-layer capacitance, and a capacitance retention rate of 92.9% after 10,000 cycles of constant current charging and discharging. Therefore, using CC as the flexible substrate and transition metal sulphides as the active material is an effective strategy for constructing high-performance flexible supercapacitors.

Exploring the photo-induced charge transfer behavior of Cs3Bi2I9 and BiI3 using in-situ surface photovoltage spectroscopy

This letter compared the photo-induced charge carrier properties of Cs3Bi2I9 and BiI3 deposited on conductive glass using surface photovoltage spectroscopy. The study showed that the higher photocurrent in BiI3 cannot be solely attributed to its extended absorbance range. The charge transfer capability of the photoactive layer was found to be a critical factor in determining photocurrent. The study also revealed better transfer of photo-induced electron-hole pairs and higher surface electron concentration in BiI3. Additionally, light-chopping-frequency-dependent surface photovoltage measurements showed that photogenerated charge carriers can be separated more effectively and in a shorter illumination period in BiI3 than in Cs3Bi2I9.

Synthesis and photoelectrochemical performance of Co doped SrTiO3 nanostructures photoanode

AbstractIt is pertinent to realize that scientific research indicates that the most promising method for producing H2 is photo electrochemical water splitting through a photo anode. Cobalt‐doped SrTiO3 (Co‐SrTiO3) composite nanostructures were created in this study via hydrothermal synthesis. The impact of cobalt concentration change on Co‐SrTiO3 has been identified using morphological, structural, and photo electrochemical research. Surface morphology of pure SrTiO3 nanoparticles using SEM and TEM reveals that the particles are intermittently agglomerated. The inclusion of Cobalt lowered the particle size of the nanostructures to 23 nm than pure SrTiO3 (41 nm). In addition, the peak profile has been influenced by cubic phase also identified from the x‐ray diffraction analysis. The purity and composition of the materials were revealed by XPS analysis. The Co‐SrTiO3 composite's produced the best charge transfer and recombination capabilities at 3% Co doping, according to electrochemical chemical impedance (EIS) spectroscopy. At 0.2 V applied potential, the obtained 3% Co‐doped SrTiO3 photoanode system displays a photocurrent density of around 3.45 mA/cm2. The outcomes show that a promising application for the Co‐doped SrTiO3 photoanode in photoelectrochemical water splitting.

One-dimensional carbon based nanoreactor fabrication by electrospinning for sustainable catalysis.

An efficient and economical electrocatalyst as kinetic support is key to electrochemical reactions. For this reason, chemists have been working to investigate the basic changing of chemical principles when the system is confined in limited space with nanometer-scale dimensions or sub-microliter volumes. Inspired by biological research, the design and construction of a closed reaction environment, namely the reactor, has attracted more and more interest in chemistry, biology, and materials science. In particular, nanoreactors became a high-profile rising star and different types of nanoreactors have been fabricated. Compared with the traditional particle nanoreactor, the one-dimensional (1D) carbon-based nanoreactor prepared by the electrospinning process has better electrolyte diffusion, charge transfer capabilities, and outstanding catalytic activity and selectivity than the traditional particle catalyst which has great application potential in various electrochemical catalytic reactions.

Semitransparent organic solar cells based on low temperature processed PEIE as electron transport layer with enhanced charge transfer ability

In inverted structure-based semitransparent organic solar cells (OSCs), the electron transport layer (ETL) plays a crucial role in the improvement of the transparent cathode efficiency in collecting and extracting negative charge carriers. Zinc oxide (ZnO) thin film prepared by zinc acetate dihydrate precursor with various benefits is generally used as ETL. However, high temperature, less charge transfer ability, and irregular film surface due to fiber-like domain formation limit the device performance. In this work, a new approach is presented by using low-temperature processed polyethylenimine ethoxylated (PEIE) as ETL in semitransparent OSCs fabricated in an ambient environment with a blend of low-bandgap donor polymer PTB7-Th, and fullerene acceptor, PC71BM, based active layer. For semitransparent OSCs, the thickness of the silver electrode has been varied from 55 nm to 25 nm to investigate its effect on the electrical and optical properties of the devices. The power conversion efficiencies (PCE) of 5.1% and 4.6% were achieved for semitransparent devices (25 nm thickness of silver electrode) for PEIE and ZnO ETLs, respectively. Similarly, PCE of 7% and 6.7% have been achieved for opaque devices (85 nm thickness of silver electrode) using PEIE and ZnO ETLs, respectively. PEIE based devices with 25 nm Ag demonstrate about 25%–30% transparency. The impedance spectroscopy measurements indicate low interfacial contact resistance and fast charge transfer capability for PEIE interlayer-based devices compared to the ZnO based devices. The encapsulated semitransparent devices processed and stored in ambient conditions with PEIE and ZnO ETLs were found to retain ≈80% performance for up to 45 days.

Utilizing three-dimensional ordered macroporous NiFe2O4 Loaded With g-C3N4 as a heterogeneous photo-Fenton catalyst for tetracycline degradation

Heterogeneous photo-Fenton technology, efficiently utilizing the solar energy and hydrogen peroxide, which combines photocatalysis and Fenton reaction, is one of the most efficient methods for eliminating organic contaminants. Here, graphitic carbon nitride (CN) and three-dimensionally ordered macroporous (3DOM) nickel ferrite (NFO) were combined to create highly catalytically active CN/3DOM-NFO composites. The composites were characterized with XRD, SEM, TEM, HRTEM, XPS, BET, DRS, and PL. And tetracycline (TC) photo-Fenton degradation catalytic activity of the composites was evaluated. The results showed that under visible light irradiation, the maximum rate constants of TC degradation of 10CN/3DOM-NFO were 7.3 times and 5.4 times that of pure g-C3N4 and bulk NFO, respectively. The optimum apparent reaction rate constant can reach as high as 0.0618 min−1 due to the synergistic interaction between the increased specific area and excellent charge carrier separation and transfer capabilities, resulting from the CN/3DOM-NFO heterojunction and the 3DOM structure, respectively. Finally, the mechanism of photo-Fenton-catalyzed degradation is briefly discussed. And this research reveals a new strategy to improve the efficiency of photo-Fenton-catalyzed degradation.

Facile in-situ grown spinel MnCo2O4/MWCNT and MnCo2O4/Ti3C2 MXene composites for high-performance asymmetric supercapacitor with theoretical insight

The logical construction of electrode materials along with greater electrochemical features and solid architectural design is a strategic approach for boosting the electrochemical performance of supercapacitors. However, it is tough and complicated to develop diverse composite materials with better electronic conductivity and greater specific capacitance via rapid and cost-effective synthesis procedures. Herein, we propose a straightforward and simple approach by employing the hydrothermal technique for the synthesis of spinel MnCo2O4 composite nanostructures using 1D MWCNT and 2D MXene (Ti3C2Tx) materials with detailed analysis of the supercapacitor performance as compared to existing literature on similar studies. The MCO/TCX (MnCo2O4/Ti3C2Tx) composite shows an impressive capacitance of 860.22 F/g at a current density of 2 A/g after electrochemical optimization. Furthermore, an asymmetric supercapacitor device (ASCs) was constructed using MCO and its composites MCO/MWCNT and MCO/TCX as a positive, and AC was employed as a negative electrode to test its device capability. Comparatively, the MCO/TCX//AC SC device demonstrated exceptional energy storage properties with a better specific capacitance value of 126.58 F/g at 0.8 A/g of current density, an elevated energy density of 40 Wh/kg, with a power density of 4828 W/kg along a capacitance retention rate of 87 % over 5000 cycles, suggesting better cycle life. Whereas, the MCO/MWCNT//AC device shows a better cycling performance of 91 % after 5000 cycles with a superior energy and power density of 27.04 Wh/kg and 1448 W/kg respectively. Also the theoretical insight for further understanding of the charge-storage mechanism through DFT calculations provides an estimate of electronic properties and quantum capacitance calculated for the pristine MCO and its hybrids with CNT and Ti3C2Tx MXene and information on the interactions between orbitals, the bonding process, and the charge transfer capabilities of each electrode material. The theoretical studies also confirm that the electronic properties and therein charge storage performance have an increasing trend in the order of MCO < MCO/CNT < MCO/TCX consistent with the experimental findings. Additionally, these simulations conclude that the hybrid MCO/TCX has the largest quantum capacitance which is in accordance with the findings of the experiments. The improved performance of MCO/TCX is due to the enlarged surface area that allows higher charge transfer from TCX to MCO. The charge transferred from the C 2p orbital of TCX to the Mn 3d orbital of MCO is the leading cause for the capacitance improvement mechanism of hybrid MCO/TCX. This work offers a simple procedure for developing energy storage devices using spinel MnCo2O4-based composite electrode materials supported by 1D carbon nanotube and 2D MXene that offer superior electrochemical performance and the fabricated electrodes that could be employed further for energy storage-based applications.

Double-Confined Ultrafine Cobalt Clusters for Efficient Peroxide Activation.

The construction of highly active catalysts presents great prospects, while it is a challenge for peroxide activation in advanced oxidation processes (AOPs). Herein, we facilely developed ultrafine Co clusters confined in mesoporous silica nanospheres containing N-doped carbon (NC) dots (termed as Co/NC@mSiO2) via a double-confinement strategy. Compared with the unconfined counterpart, Co/NC@mSiO2 exhibited unprecedented catalytic activity and durability for removal of various organic pollutants even in extremely acidic and alkaline environments (pH from 2 to 11) with very low Co ion leaching. Experiments and density functional theory (DFT) calculations proved that Co/NC@mSiO2 possessed strong peroxymonosulphate (PMS) adsorption and charge transfer capability, enabling the efficient O-O bond dissociation of PMS to HO• and SO4•- radicals. The strong interaction between Co clusters and mSiO2 containing NC dots contributed to excellent pollutant degradation performances by optimizing the electronic structures of Co clusters. This work represents a fundamental breakthrough in the design and understanding of the double-confined catalysts for peroxide activation.

Minimized Energy Loss at the Buried Interface of p‐i‐n Perovskite Solar Cells via Accelerating Charge Transfer and Forming p–n Homojunction

AbstractThe energy loss (Eloss) aroused by inefficient charge transfer and large energy level offset at the buried interface of p‐i‐n perovskite solar cells (PVSCs) limits their development. In this work, a BF4− anion‐assisted molecular doping (AMD) strategy is first proposed to improve the charge transfer capability of hole transport layers (HTLs) and reduce the energy level offset at the buried interface of PVSCs. The AMD strategy improves the carrier mobility and density of poly[bis(4‐phenyl) (2,4,6‐trimethylphenyl) amine] (PTAA) and poly[N,N′‐bis(4‐butilphenyl)‐N,N′‐bis(phenyl)‐benzidine] (Poly‐TPD) HTLs while lowering their Fermi levels. Meanwhile, BF4− anions regulate the crystallization and reduce donor‐type iodine vacancies, resulting in the energetics transformation from n‐type to p‐type on the bottom surface of perovskite film. The faster charge transfer and formed p–n homojunction reduce charge recombination and Eloss at the HTL/perovskite buried interface. The PVSCs utilizing AMD treated PTAA and Poly‐TPD as HTLs demonstrate a highest power conversion efficiency (PCE) of 24.26% and 22.65%, along with retaining 90.97% and 85.95% of the initial PCE after maximum power point tracking for 400 h. This work provides an effective way to minimize the Eloss at the buried interface of p‐i‐n PVSCs by accelerating charge transfer and forming p–n homojunctions.

P and Se Binary Vacancies and Heterostructures Modulated MoP/MoSe2 Electrocatalysts for Improving Hydrogen Evolution and Coupling Electricity Generation.

It is not enough to develop an ideal hydrogen evolution reaction (HER) electrocatalysts by single strategy. Here, the HER performances are significantly improved by the combined strategies of P and Se binary vacancies and heterostructure engineering, which is rarely explored and remain unclear. As a result, the overpotentials of MoP/MoSe2 -H heterostructures rich in P and Se binary vacancies are 47 and 110mV at 10mAcm-2 in 1m KOH and 0.5m H2 SO4 electrolytes, respectively. Especially, in 1m KOH, the overpotential of MoP/MoSe2 -H is very close to commercial Pt/C at the beginning and even better than Pt/C when current density is over 70mAcm-2 . The strong interactions between MoSe2 and MoP facilitate electrons transfer from P to Se. Thus, MoP/MoSe2 -H possesses more electrochemically active sites and faster charge transfer capability, which are all in favor of high HER activities. Additionally, Zn-H2 O battery with MoP/MoSe2 -H as cathode is fabricated for simultaneous generation of hydrogen and electricity, which displays the maximum power density of up to 28.1mWcm-2 and stable discharging performance for 125h. Overall, this work validates a vigorous strategy and provides guidance for the development of efficient HER electrocatalysts.

Silver Nanoparticles Anchored on Single-Walled Carbon Nanotubes via a Conjugated Polymer for Enhanced Sensing Applications.

Single-walled carbon nanotubes (SWCNTs) are candidate matrices for loading metal nanoparticles (NPs) for sensor and catalytic applications owing to their high electron conductivity and mechanical strength, larger surface area, excellent chemical stability, and ease of surface modification. The performance of the formed NP/SWCNT composites is dependent on the NP size, the physical and chemical interactions between the components, and the charge transfer capabilities. Anchoring metal complexes onto the surface of SWCNTs through noncovalent interactions is a viable strategy for achieving high-level metal dispersion and high charge transfer capacities between metal NPs and SWCNTs. However, traditional metal complexes have small molecular sizes, and their noncovalent interactions with SWCNTs are limited to provide excellent sensing and catalytic capability with restricted efficiency and durability. Here, we selected poly(9,9-di-n-dodecylfluorenyl-2,7-diyl-alt-2,2'-bipyridine-5,5') (PFBPy) to increase the noncovalent interactions between silver nanoparticles (AgNPs) and SWCNTs. A silver triflate (Ag-OTf) solution was added into a PFBPy-wrapped SWCNT solution to form Ag-PFBPy complexes on the nanotube surface, after which Ag+ was photoreduced to AgNPs to form a Ag-PFBPy/SWCNT composite in the solution. In various feeding molar ratios of Ag-OTf over the BPy unit (0.4-50), the size of the formed AgNPs may be well-controlled at sub-nm levels to provide them with an energy level comparable to that of the SWCNTs. Additionally, the 2,2'-bipyridine (BPy) unit of the polymer provided a coordinating interaction with Ag+ and the formed AgNPs as well. The 5,5'-linage of BPy with the fluorene unit in PFBPy ensured a straight main chain structure to retain strong π-π interactions with nanotubes before and after Ag+ chelation. All of these factors confirmed a tight contact between the formed AgNPs and SWCNTs, promoting the charge transfer between them and enhancing the sensing capabilities with a 5-fold increase in humidity sensing sensitivity.

Efficient Environmentally Friendly Flexible CZTSSe/ZnO Solar Cells by Optimizing ZnO Buffer Layers.

Flexible CZTSSe solar cells have attracted much attention due to their earth-abundant elements, high stability, and wide application prospects. However, the environmental problems caused by the high toxicity of the Cd in the buffer layers restrict the development of flexible CZTSSe solar cells. Herein, we develop a Cd-free flexible CZTSSe/ZnO solar cell. The influences of the ZnO films on device performances are investigated. The light absorption capacity of flexible CZTSSe solar cells is enhanced due to the removal of the CdS layer. The optimal thickness of the ZnO buffer layers and the appropriate annealing temperature of the CZTSSe/ZnO are 100 nm and 200 °C. Ultimately, the optimum flexible CZTSSe/ZnO device achieves an efficiency of 5.0%, which is the highest efficiency for flexible CZTSSe/ZnO solar cells. The systematic characterizations indicate that the flexible CZTSSe/ZnO solar cells based on the optimal conditions achieved quality heterojunction, low defect density and better charge transfer capability. This work provides a new strategy for the development of the environmentally friendly and low-cost flexible CZTSSe solar cells.

Constructing highly active interface between layered Ni(OH)2 and porous Mo2N for efficient electrocatalytic oxygen evolution reaction

Layered Ni(OH)2 materials are cheap and efficient electrocatalyst for water splitting. However, pristine Ni(OH)2 materials usually show poor activity due to the low activity sites and poor conductivity in electrochemical reactions. Herein, layered Ni(OH)2 nanosheets are grown on the porous Mo2N particles for improved interfacial active sites and enhanced conductivity in the oxygen evolution reaction (OER). The OER overpotential of the optimized Mo2N/Ni(OH)2 composite material is distinctly reduced compared with pristine Ni(OH)2. In addition, the optimized Mo2N/Ni(OH)2 composite material exhibits favorable durability in alkaline electrolyte. Further electrochemical investigation reveals that the Mo2N/Ni(OH)2 composite materials produce increased charge transfer capability and electrochemical active surface area. Theoretical calculation study demonstrates that a redistribution of electron occurred at the interface of Ni(OH)2 and Mo2N, which results in the decrease of energy barrier for the adsorption of OER reactive intermediates at the interfacial atoms. The enhanced performance of OER is thus mainly come from the constructed interface between layered Ni(OH)2 and porous Mo2N. This work gives a feasible method to develop cheap and efficient electrocatalysts for water splitting.

Boron-doped diamond nanofilm on a Ti substrate possessing fast charge transfer: Strategy toward cost-effective electrochemical oxidation of refractory organic pollutants

This study suggests a breakthrough toward the high-cost issue of electrochemical degradation of refractory organic pollutants caused by adopting a boron-doped diamond (BDD) electrode. Specifically, effect of charge transfer capability of the BDD electrode on electrochemical oxidation of 4-chlorophenol (4-CP) and perfluorooctanoic acid (PFOA) is explored. Thin BDD nanofilm (thickness of ~400 nm) on a Ti substrate (BDD@Ti) was prepared to overcome the delamination of the BDD on the Ti via hot-filament chemical vapor deposition under optimum conditions. When compared with a commercial electrode (C-BDD, micron BDD film on a Nb substrate), inevitable metal-carbide layer formed at interface between BDD film and metal substrate is much thinner than that of C-BDD. The unique structural features of BDD@Ti facilitate a much faster charge transfer and degradation of both 4-CP and PFOA than C-BDD, which is attributed to shortening of electron pathway from surface to conductive substrate.

Triazine-based covalent organic framework/carbon nanotube fiber nanocomposites for high-performance supercapacitor electrodes

In this study we synthesized the triazine-based two-dimensional covalent organic frameworks (COFs) TPTP-COF and TPDA-COF through Schiff base (imine) condensations of 2,4,6-tris(4-formylphenyl)-1,3,5-triazine (TPT-3CHO) with 2,4,6-tris(4-aminophenyl)triazine (TPT-3NH2) and diaminoanthraquinone (DAAQ), respectively. Moreover, we used carbon nanotube fibers (f-CNFs) as a template to synthesize TPTP-COF@f-CNF and TPDA-COF@f-CNF nanocomposite materials. X-ray diffraction image analysis revealed that our two COF materials possessed hexagonal crystal structures, with the crystallinity of TPTP-COF being much higher than that of TPDA-COF. Through simulations using Material Studio software, we determined an AA stacking structure for TPTP-COF and an AB stacking structure for TPDA-COF. These COF materials had high specific surface areas, charge transfer capability, and high redox properties, making them suitable for use in supercapacitor applications. TPTP-COF– and TPDA-COF–based electrodes provided specific capacitances of 577.4 and 640.4 F g−1, respectively, at a scan rate of 5 mV s−1. The specific capacitance of the TPTP-COF@f-CNF and TPDA-COF@f-CNF electrodes decreased upon increasing the f-CNF content. The maximum specific capacitances of TPTP-COF– and TPDA-COF–based symmetric supercapacitor devices were 56.4 and 70.6 F g−1, respectively. The TPTP-COF– and TPDA-COF–based devices both exhibited good electrochemical stability, preserving 78.60 and 81.54%, respectively, of their initial capacitances after 10,000 cycles. The energy density and power density of the TPDA-COF–based device were slightly better than those of the TPTP-COF–based device.

Design of novel metal chalcogenide photoanodes supported with reduced graphene oxide for improvement of photoelectrochemical hydrogen evolution

Designing new photoanodeswith high efficiency provides an effective route to develop photoelectrochemical hydrogen production.In this work, quaternary metal chalcogenides (CdZnMSSe (M: Ni, Cu, Mo)) and reduced graphene oxide- quaternary metal chalcogenide (RGO-CdZnMSSe) composite films are fabricated by simple one-step electrodeposition process. The photoanodes formed of quaternary metal chalcogenides and the incorporation of RGO in these composite films increase charge transfer capability and separation ability compared to cadmium-based photoanodes, leading to enhancement of the photoelectrochemical hydrogen production activity. A superior photocurrent response is recorded for RGO(0.25)-Cd0.8Zn0.2Ni0.2S0.2Se0.8 (5.34 mA cm−2 at 0.8 V vs RHE). In addition, the maximum ABPE value of RGO(0.25)-Cd0.8Zn0.2Ni0.2S0.2Se0.8 is determined as 1.95%. The achieved results offer a new insight into highly efficient next generation-photoanodes to convert solar energy to hydrogen.

Cu/CuO-Doped ZnO Nanocomposites via Solution Combustion Synthesis for Catalytic 4-Nitrophenol Reduction.

The synthesis of optoelectrically enhanced nanomaterials should be continuously improved by employing time- and energy-saving techniques. The porous zinc oxide (ZnO) and copper-doped ZnO nanocomposites (NCs) were synthesized by the time- and energy-efficient solution combustion synthesis (SCS) approach. In this SCS approach, once the precursor-surfactant complex ignition point is reached, the reaction starts and ends within a short time without the need for any external energy. The TGA-DTA analysis confirmed that 500 °C was the point at which stable metal oxide was obtained. The doping and heterojunction strategy improved the optoelectric properties of the NCs more than the individual constituents, which then enhanced the materials' charge transfer and optical absorption capabilities. The porosity, nanoscale crystallite size (15-50 nm), and formation of Cu/CuO-ZnO NCs materials were confirmed from the XRD, SEM, and TEM/HRTEM analyses. The obtained d-spacing values of 0.275 and 0.234 nm confirm the formation of ZnO and CuO crystals, respectively. The decrease in photoluminescence intensity for the doped NCs corroborates a reduction in electron-hole recombination. On the Mott-Schottky analysis, the positive slope for ZnO confirms the n-type character, while the negative and positive slopes of the NCs confirm the p- and n-type characters, respectively. A diffusion-controlled type of charge transfer process on the electrode surface was confirmed from the cyclic voltammetric analysis. Thus, the overall analysis shows the applicability of the less expensive and more efficient SCS for several applications, such as catalysis and sensors. To confirm this, an organic catalytic reduction reaction of 4-nitrophenol to 4-aminophenol was tested. Within three and a half minutes, the catalytic reduction result showed the great potential of NCs over ZnO NPs. Thus, the energy- and time-saving SCS approach has a great future outlook as an industrial pollutant catalytic reduction application.

Integration of Conductive Nanocomposites and Nanomembranes for High‐Performance Stretchable Conductors

Stretchable metallic nanocomposites are viable material candidates for high‐performance soft biointerfacing electrodes. However, it is still challenging to fabricate a stretchable metallic nanocomposite that features outstanding charge transfer capability and low impedance as well as high conductivity and mechanical stability. Herein, a material strategy for a stretchable conductor that meets such requirements by integrating stretchable conductive nanocomposites with stretchable conductive nanomembranes (NMs) is presented. The silver nanowire (Ag NW) NM fabricated by the float assembly method is integrated with the Ag NW nanocomposite prepared by the drop‐casting method. The compactly assembled NWs in the NM maximize conductivity by reinforcing the percolation networks of the nanocomposite. Moreover, the NM lowers impedance by allowing efficient charge transfer to the target tissue through the exposed NWs. After their integration, a high conductivity of ≈35 700 S cm−1 is obtained, and the impedance is decreased by ≈88.9% (at 1000 Hz) in comparison with the original Ag NW‐based nanocomposite (i.e., without integration of the NM). The soft bioelectrode using the stretchable conductor successfully records electrograms from the rat heart, recognizes various arrhythmic events, and applies feedback pacing.

Efficient side-chain engineering of thieno-imidazole salt-based molecule to boost the optoelectronic attributes of organic solar cells: A DFT approach

This study focused on modeling and density functional theory (DFT) analysis of reference (AI1) and designed structures (AI11-AI15), based on the thieno-imidazole core, in order to create profitable candidates for solar cells. All the optoelectronic properties of the molecular geometries were computed using DFT and time dependent-DFT approaches. The influence of terminal acceptors on the bandgaps, absorption, hole and electron mobilities, charge transfer capabilities, fill factor, dipole moment, etc. Of the recently designed structures (AI11-AI15), as well as reference (AI1), were evaluated. Optoelectronics and chemical parameters of newly architecture geometries were shown to be superior to the cited molecule. The FMOs and DOS graphs also demonstrated that the linked acceptors remarkably improved the dispersion of charge density in the geometries under study, particularly in AI11 and AI14. Calculated values of binding energy and chemical potential confirmed the thermal stability of the molecules. All the derived geometries surpassed the AI1 (Reference) molecule in terms of maximum absorbance ranging from 492 to 532 nm (in chlorobenzene solvent) and a narrower bandgap ranging from 1.76 to 1.99eV. AI15 had the lowest exciton dissociation energy of 0.22eV as well as lowest electrons and hole dissociation energies, while AI11 and AI14 showed highest VOC, fill factor, power conversion efficiency (PCE), IP and EA (owing to presence of strong electron pulling cyano (CN) moieties at their acceptor portions and extended conjugation) than all the examined molecules, implying that they could be used to build elite solar cells with enhanced photovoltaic attributes.

Charge localization induced by Fe doping in porous Bi5O7I Micro-flower for enhanced photoreduction of CO2 to CO

The bismuth-rich bismuth oxyhalide materials exhibit prominent photocatalytic CO2 reduction (PCR) performance owing to the considerable negative conduction band potential and unique intrinsic internal electric field. However, it possesses poor capture ability of CO2 molecule due to the intrinsically weak adsorption, greatly limiting its further PCR improvement. Herein, we modulate the spatial charge redistribution over hierarchically Bi5O7I micro-flower through a facile and cost-efficient iron doping strategy, achieving significantly enhanced CO2 capture capacity. Mechanistic studies indicate that the promoted adsorption ability originates from the localized electrons around the doped Fe sites. Benefiting from the resultant unique electronic structures, the Fe doped Bi5O7I micro-flowers also exhibit remarkably improved harvest of visible light and promoted charge separation and transfer capability, thus finally achieving a notably boosted photocatalytic CO evolution rate of 12.02 μmol·g−1·h−1 without any sacrifice agents.