Transport Ability Research Articles

Simultaneous modification of interface and modulation of crystal growth by deep eutectic solvent for FACs-Based perovskite solar cells

Improving the interface property and crystallographic orientation of perovskite films has been considered as the bottleneck to improve the optoelectronic performance of perovskite solar cells (PSCs). However, the precise manipulation of preferential crystal orientation by interfacial layers and their underlying impact mechanism on the device performance is still not well understood. In this study, deep eutectic solvent (DES), which is prepared by mixing choline chloride (Chcl) and propanedioic acid (PA) in a molar ratio of 1:1, is employed as a buried interface layer to finely adjust the preferred crystal orientation of the FACs-based perovskite. On the one hand, the DES can modify SnO2, which is conducive to improving electron extraction and transport abilities. On the other hand, the DES can interact with perovskite by forming coordination bonds, electrostatic interactions, and hydrogen bonds, which is beneficial for inducing perovskite crystal orientation along the (100) crystal plane, causing reduced trap density and hence retarded non-radiative recombination of PSCs. The preferred crystal orientation enhances the quality of the perovskite film. Consequently, a power conversion efficiency (PCE) of 21.11 % is obtained, which is higher than 18.11 % of the pristine PSC. Moreover, the unencapsulated device maintains 87 % of its initial PCE after aging for more than 1100 h in the air. This work presents a feasible method for controlling perovskite orientation growth by interface DES layer.

Volatile Solid‐Assisted Molecular Assembly Enables Eco‐Friendly Processed Organic Photovoltaic Cells with High Efficiency and Photostability

AbstractAchieving environmentally friendly solvent‐processed high‐performance organic photovoltaic cells (OPVs) is a crucial step toward their commercialization. Currently, OPVs with competitive efficiencies rely heavily on harmful halogenated solvent additives. Herein, the green and low‐cost 9‐fluorenone (9‐FL) is employed as a solid additive. By using the o‐xylene/9‐FL solvent system, the PM6:BTP‐eC9‐based devices deliver power‐conversion efficiencies of 18.6% and 17.9% via spin‐coating and blade‐coating respectively, outperforming all PM6:Y‐series binary devices with green solvents. It is found that the addition of 9‐FL can regulate the molecular assembly of both PM6 and BTP‐eC9 in film‐formation (molecule‐level mixing) and post‐annealing (thermal‐assisted molecular reorganization with additive volatilization) stages, so as to optimize the blend morphology. As a result, the charge transport ability of donor and acceptor phases are simultaneously enhanced, and the trap‐assisted recombination is reduced, which contributes to the higher short‐circuit current density and fill factor. Moreover, the generation of photo‐induced traps is significantly suppressed, resulting in improved stability under illumination. It is further demonstrated the excellent universality of 9‐FL in various photoactive systems, making it a promising strategy to advance the development of eco‐friendly OPVs.

Promoted polysulfide conversion process and improved rate performance by tin atom modified carbon in Li-S batteries

Dissolution of polysulfides limits the improvement of rate performance in Li-S batteries. Introducing catalytic agents is the key to promote polysulfide conversion process and improve rate performance of Li-S batteries. Both metallic atoms catalysts and metal sulfide catalysts can promote polysulfide conversion process. However, the comparison of catalyzing abilities between metallic atoms catalysts and metal sulfide catalysts in Li-S batteries still needs to be studied. SnS modified carbon (C/SnS) and Sn atom modified carbon (C/Sn) are obtained by controlling hydrothermal and carbonization processes in this paper. Electrochemical performance of C/SnS/S and C/Sn2S3/S composite electrodes are also studied, which are obtained by loading sulfur on C/SnS and C/Sn. Results show that C/Sn2S3/S composite electrodes possess higher rate performance (553 mAh·g−1 at 5C) than C/SnS/S composite electrodes, which is ascribe to stable catalyzing abilities of Sn atom modified carbon. Electron transportation abilities and Li-ion diffusion process are both promoted in C/Sn2S3/S composite electrodes. The comparison of catalyzing abilities between C/SnS and C/Sn composites provides reference for design and regulation of composite structures.

In-situ experimental investigations to study the impact of mechanical compression on the PEMFC - analysis of the global cell performance

An appropriate clamping pressure is required to ensure the gas-tight operation of a PEMFC assembly and to improve the contacts (i.e. mechanical, thermal, electrical) between its components. However, an excessive mechanical load may also worsen the cell performance, in particular through the reduction in the porosity and mass transport ability of the Gas Diffusion Layers. In this study, the effects of mechanical compression on the global performance of a 225 cm2 PEMFC assembly are investigated by implementing cell voltage monitoring and polarisation curve measurements. The investigations are carried out with gradual increase / decrease and randomised load compression protocols applied using a specially designed mechanical compression unit. 12 levels of mechanical compression are considered, ranging from 0.35 to 2 MPa with steps of 0.15 MPa. The results of the characterisation techniques show that the PEMFC performance is improved at all tested operating conditions for mechanical compression up to 1.55 MPa. This finding is attributed to the dominant reduction of the ohmic drop against the increase of the gas diffusion losses. It is also shown that compressing the PEMFC beyond 1.55 MPa would not lead to any further improvement of the global cell voltage output. This may even worsen the cell electrical characteristics by affecting its mass transport issues.

A stable and efficient hydrogel/sponge solar evaporator with splendid water supply

Solar-driven interfacial evaporation is an effective and realizable way of water purification. However, a short supply of water limits the evaporation performance of evaporator greatly. Here, an integrated photothermal evaporator owning double-layer structure of hydrogel and sponge with strong water transport ability is successfully prepared by cross-linking and dopamine modification. Abundant pores and hydrophilic functional groups in hydrogel and modified sponge benefit to enhance water transport of the whole evaporator and further relieve salt accumulation. Carbon black having the advantages of low cost and full spectrum absorption is dispersed into hydrogel networks to improve the capacity of photothermal conversion. Under the illumination of 1 kW m−2, the evaporator exhibits an excellent evaporation rate of 1.71 kg m-2h−1, corresponding to an evaporation efficiency of 93.8 %. Furthermore, the evaporator shows excellent stability during 8 cycles of solar evaporation. And the evaporator demonstrates superior salt tolerance in 3.5 wt% NaCl solution during the continuous evaporation of 8 h and has an outstanding efficiency of 99.8 % in 4-NP wastewater purification. The outdoor experiment proves that the evaporator of 1 m2 can produce 7.28 L of fresh water per day, which meet the drinking water demand of two adults. The hydrogel/sponge integrated photothermal evaporator has great application potential in seawater desalination and wastewater purification.

Stable cyclic ether as an electrolyte additive for high-performance lithium metal batteries.

Introducing a methyl group into 1,3-dioxolane (DOL) to obtain a stable cyclic ether, 4-methyl-1,3-dioxolane (4-Me DOL), allows it to be used as an additive in LiPF6-based carbonate electrolytes. The addition of 4-Me DOL can form a stable SEI with good Li+ transport ability, which can simultaneously improve the rate capability and cycling performance of lithium metal batteries.

A bioswitchable siRNA delivery system: RNAi therapy based on tetrahedral framework nucleic acids for bone defect repair.

Craniofacial bone defects, caused by trauma, congenital abnormalities, or various diseases, present a significant challenge in regenerative medicine. One approach to addressing this problem is the use of RNA interference (RNAi) technology with small interfering RNA (siRNA). CKIP-1 is a negative regulatory molecule for bone formation. However, direct applications of CKIP-1 siRNA for bone defects are still limited. The instability and poor cellular uptake ability of CKIP-1 siRNA restrict its clinical applications. A new drug delivery system is critically needed to enhance the effectiveness and potential applications of CKIP-1 siRNA. Tetrahedral framework nucleic acid (tFNA) is a promising drug delivery system due to its stability and transport abilities. In this study, we developed a bioswitchable siRNA delivery system (BiRDS) based on tFNA to carry CKIP-1 siRNA and examined its effect on bone defect repair. siRNA was successfully loaded into the tFNA core, forming BiRDS, which improved siRNA stability and cellular uptake. After entering cells, BiRDS exposed siRNA, enhancing CKIP-1 silencing efficiency. This system significantly promoted osteogenic differentiation and bone regeneration in rat mandibular bone defects, offering a new strategy for bone regeneration therapy.

Transportation and Canal Centering Ability of Reciprocating vs Full Rotating Files after Instrumenting Severely Curved Canals. A Cone Beam Computed Tomography Comparative Study

Transportation and Canal Centering Ability of Reciprocating vs Full Rotating Files after Instrumenting Severely Curved Canals. A Cone Beam Computed Tomography Comparative Study

Evaluation of Canal Transportation and Centering Ability of RaCe and Af f-one Systems by Cone-beam Computed Tomography: An in Vitro Study.

Rotary systems have made significant advances to improve their root canal preparation efficacy. These instruments can properly preserve the root canal anatomy and morphology. The present in vitro study aimed to compare canal transportation and centering ability of RaCe and Af f-one systems using cone-beam computed tomography. Thirty-six mandibular molars were included. The samples were randomly assigned to two groups (n=18): group 1, RaCe, and group 2, Af f-one. Canal preparation was conducted using the respective files according to the manufacturers' instructions. The cone-beam computed tomographic scanning of the samples was performed before and after preparation. The data were analyzed by using two-way ANOVA. In both the RaCe and Af f-one rotary systems, canal centrality and transportation were similar at coronal, middle, and apical cross-sections. In addition, canal transportation and centrality were identical in the RaCe and Af f-one rotary files (P<0.05). The two studied rotary systems did not exhibit significant differences in root canal transportation and preservation of root canal centrality in the apical, middle, and coronal thirds.

Supramolecular DNA nanogels through host-guest interaction for targeted drug delivery.

DNA hydrogels have been demonstrated with the advantages of good stability, easy modification, and extraordinary biocompatibility, which enables their great application prospects in biosensing, tissue engineering, and biomedicine. Based on the host-guest recognition properties of cucurbit[8]uril (CB[8]), we proposed a general method for constructing functional supramolecular DNA nanogels. Guest molecules have been conjugated into the DNA building units, which could be further crosslinked with CB[8] to construct supramolecular DNA nanogels. At the same time, the aptamer has also been modified into the hydrogel network to achieve cell targeting. These supramolecular DNA nanogels have been demonstrated with a controllable size and multiple stimuli responses, in addition to the excellent biocompatibility, stability and good targeting drug transport ability. Such a host-guest based strategy will provide a molecular library as a "toolbox" for the functionalization of DNA nanogels.

EXPLORING THE HEAT TRANSFER PERFORMANCE OF CYLINDRICAL HEAT PIPES WITH VARIED MOLAR Ag-DOPED GO HYBRID NANOFLUIDS - AN EMPIRICAL STUDY

In our modern era of technological advancements, the widespread use of high-powered electronic and electrical devices has resulted in the release of excessive heat, posing a threat to the environment. To address this issue, heat pipes have emerged as a promising solution for effective heat removal. As researchers strive to improve their performance, various approaches have been explored. This study took a unique approach by investigating the performance of miniature cylindrical copper sintered heat pipes using different molar concentrations (0.03 M, 0.06 M, and 0.09 M) of Ag-doped GO hybrid nanofluids, with a weight percentage of 0.05 wt.&amp;#37; as the working fluid. The study carefully assessed the heat transport capabilities of these nanofluids within the heat pipe, considering a range of heat inputs (10-130 W) in the evaporator section and different mass flow rates (8.33 g/s, 16.66 g/s, and 25 g/s) of the cooling fluid in the condenser section. The findings revealed that the 0.09-M Ag-GO nanofluid demonstrated superior performance, with a remarkable 50.48&amp;#37; reduction in thermal resistance and a significant 27.52&amp;#37; improvement in wall temperature distribution, particularly at a mass flow rate of 16.66 g/s and a heat input of 100 W. It reveals that altering the molarity of nanoparticles in hybrid nanofluids has the potential to enhance the heat transport abilities of heat pipes.

Carrier mobility and optical properties of a type-II GaSe/ZnS heterostructure as a photocatalyst: a first-principles study.

In this paper, a new GaSe/ZnS van der Waals heterostructure (vdWH) was constructed and a systematic analysis of the electronic structure, interfacial properties, and transport and photocatalytic capacity of the GaSe/ZnS vdWH was performed by using first-principles calculations. It was found that the heterostructure exhibited excellent photocatalytic performance for water splitting. The direct band gap of the heterostructure calculated using the hybrid HSE06 functional was 2.19 eV, which had a good visible light absorption ability. The electronic structure of the type-II band arrangement effectively reduced the recombination of electron-hole pairs. The heterostructure also showed excellent transport ability, and the carrier mobility of electrons and holes along different directions was greatly improved. Additionally, as the electric field strength increased, the band gap width of the GaSe/ZnS vdWH narrowed and the heterostructure characteristics transitioned from semiconductor to metal properties, which were attributed to the appearance of near-free electronic (NFE) states induced by the strong electric field. Meanwhile, the optical absorption capacity of the heterostructure was greatly improved compared to the ZnS monolayer, reaching 1.44 × 105 cm-1 at an incident photon energy of 8.65 eV. Therefore, the GaSe/ZnS vdWH was proved to be an excellent photocatalytic material for water splitting in the present study.

Porous crystalline conjugated macrocyclic materials and their energy storage applications.

Porous crystalline conjugated macrocyclic materials (CMMs) possess high porosity, tunable structure/function and efficient charge transport ability owing to their planar macrocyclic conjugated π-electron system, which make them promising candidates for applications in energy storage. In this review, we thoroughly summarize the timely development of porous crystalline CMMs in energy storage related fields. Specifically, we summarize and discuss their structures and properties. In addition, their energy storage applications, such as lithium ion batteries, lithium sulfur batteries, sodium ion batteries, potassium ion batteries, Li-CO2 batteries, Li-O2 batteries, Zn-air batteries, supercapacitors and triboelectric nanogenerators, are also discussed. Finally, we present the existing challenges and future prospects. We hope this review will inspire the development of advanced energy storage materials based on porous crystalline CMMs.

Layered double hydroxide-based electrode materials derived from metal-organic frameworks: synthesis and applications in supercapacitors.

Metal-organic frameworks (MOFs) have emerged as promising electrode materials for supercapacitors (SCs) due to their highly porous structures, tunable chemical compositions, and diverse morphologies. However, their applications are hindered by low conductivity and poor cycling performance. A novel approach for resolving this issue involves the growth of layered double hydroxides (LDHs) using MOFs as efficient templates or precursors for electrode material preparation. This method effectively enhances the stability, electrical conductivity, and mass transport ability of MOFs. The MOF-derived LDH exhibits a well-defined porous micro-/nano-structure, facilitating the dispersion of active sites and preventing the aggregation of LDHs. Firstly, this paper introduces synthesis strategies for converting MOFs into LDHs. Subsequently, recent research progress in MOF-derived LDHs encompassing pristine LDH powders, LDH composites, and LDH-based arrays, along with their applications in SCs, is overviewed. Finally, the challenges associated with MOF-derived LDH electrode materials and potential solutions are discussed.

Ultrathin Ba0.75Sr0.25TiO3 nanosheets with highly exposed {001} polar facets for high-performance piezocatalytic application.

The development of piezoelectrics with high catalytic activity to address environmental pollution and energy shortage has long been pursued. In this work, for the first time, a "three-birds-with-one-stone" strategy is proposed to design high-activity piezocatalysts. Interestingly, we achieved ultrathin, highly exposed polar facets and ferroelectric-paraelectric phase transitions in Ba1-xSrxTiO3 nanosheets simultaneously. As expected, Ba0.75Sr0.25TiO3 shows superior piezocatalytic performance for organic pollutant degradation due to its excellent flexibility, highly exposed polar area, and short carrier migration distance. Then, the piezoelectric potential distribution and electron transport ability on the interface of Ba0.75Sr0.25TiO3 were investigated through finite element method (FEM) simulation and density-functional theory (DFT) calculations, which provided a deep insight into the enhanced mechanism. This work thus presents a novel strategy for designing high-performance piezocatalysts and provides new insights for the optimization of the piezocatalytic activity by combining multiple advantages.

Fabrication and Characterization of Chitosan-Polyvinyl Pyrolidone K-30 for Creatinine Transport Membranes

The investigation of membrane-based hemodialysis is an interesting study due to its efficacy in eliminating metabolic waste compounds, such as creatinine, from the body. However, not all membrane types exhibit optimal transport capabilities, necessitating modifications. In this study, we conducted modifications on chitosan (CS) membranes by incorporating polyvinyl pyrrolidone K-30 (PVP K-30) and assessing their physicochemical characteristics. The modified membrane underwent characterization and subsequent evaluation of its transport capabilities. The primary objective of this research is to design a membrane composed of chitosan and PVP K-30 with enhanced creatinine transport capabilities. The study commenced with the fabrication of CS membranes combined with CS-PVP, involving six variations of CS and PVP K-30 with volume ratios of 5:0, 4:1, 3:2, 1:1, 2:3, and 4:1. The resulting solution was then printed into a flat sheet membrane. All completed membranes underwent comprehensive characterization, including tests for functional groups using Fourier Transform Infrared (FTIR), membrane weight and thickness, porosity, water absorption, swelling, hydrophilicity, pH resistance, and biodegradation. In the final phase, the membrane was utilized in the creatinine transport process. FTIR analysis of the CS-PVP K-30 membrane revealed O-H and N-H group spectra at wave numbers 3363.06 cm-1 and 1587.17 cm-1, indicating hydrogen bonding between the two polymers. Characterization tests demonstrated that the CS-PVP membrane exhibited increased porosity, water absorption, swelling, and hydrophilicity. In the creatinine transport test, the CS-PVP membrane demonstrated enhanced creatinine transport ability compared to the CS membrane. The highest clearance value for creatinine was observed in the CS-PVP5 membrane, with an increase in the amount of PVP K-30 correlating with an elevated creatinine clearance value. The creatinine clearance values for the CS membrane, CS-PVP1, CS-PVP2, CS-PVP3, CS-PVP4, and CS-PVP5 were 0.30, 0.36, 0.37, 0.39, 0.42, and 0.46 mg/dL, respectively.

Investigation of Pd Based Metal-Carbon As Bifunctional Electrocatalyst for OER and ORR

Developing oxygen reduction/ evolution reaction (ORR/OER) bifunctional electrocatalysts has great significance for promoting the sustainable energy conversion. Herein, Pd (5wt% only) based bimetallic catalyst adhered well on heteroatom doped conducting carbon substrate is designed and constructed. Rich defects, multiple active centers and strong synergistic effect with rapid ion/electron transport ability allow the electrocatalyst to exhibit superior performance (Li et al., 2019). Owing to its more active metal-Pd sites due to high surface area conducting carbon matrix an ultralow overpotential of 240 mV at 10 mA/cm2 for OER was obtained. It outperforms state of art RuO2 and Pt/C electrocatalyst. High half-wave potential (E1/2) of 0.821 V for ORR is comparable to commercial Pt/C (E1/2 =0.819 V) electrocatalysts was attained. The catalyst exhibits a prolonged stability in alkaline medium at 20 mA cm-2 for 24 h for OER and a small 20 mV shift in linear sweep voltammetry scan after accelerated durability test for 5000 cycles at 50mV/s for ORR. In-situ Raman analysis exhibits surface oxidation of electrocatalyst on OER in highly alkaline (1M KOH) conditions.Reference:Li, S., Hao, X., Abudula, A., & Guan, G. (2019). Nanostructured Co-based bifunctional electrocatalysts for energy conversion and storage: current status and perspectives. Journal of Materials Chemistry A, 7(32), 18674–18707. https://doi.org/10.1039/C9TA04949E

Mechanically durable MXene based nanofiber composite membranes with asymmetric superhydrophilicity/hydrophobicity for unidirectional water transport and temperature sensing

Wearable fibric materials have shown wide applications in flexible electronics, and it is desired that smart fibric/fiber materials possess excellent breathability, durability and sweat-wicking capabilities. Here, we develop an electrically conductive Janus nanofiber composite (CJNCs) with outstanding unidirectional water transportation (UWT) ability by regulating MXene nanosheet distribution. MXene/chitason are assembled on the polyurethane (PU) surface to obtain a superhydrophilic layer with a large thickness, while MXene nanosheets embedded PU nanofibres with a smaller thickness is deposited onto the superhydrophilic layer to construct a Janus structure with asymmetric wettability. The Janus structure demonstrates outstanding interfacial stability, guaranteeing the excellent durability of the UWT behavior. The UWT time can be diminished to around 10 s, and the anti-gravity water transportation time is only 18 s. In addition, CJNCs displays superior photo-thermal effect and temperature sensing behavior. This work presents an effective and facile strategy toward fabricating multifunctional fibrous materials with potential applications in smart and wearable sensing electronics.

One-step growth of RuNi-MOF nanoarrays on carbon felt host as a high-performance binder-free electrode for dual application: Ethanol fuel cell and supercapacitor

The future perspective is to develop high-efficient catalysts in next-generation energy technologies. Metal-organic frameworks (MOFs) offer a high degree of design flexibility which plays an important role as electrocatalysts. However, poor stability and low conductivity of MOFs are challenging to favorable electrocatalytic activity. Accordingly, a new and efficiently bimetallic RuNi-MOF is fabricated by in-situ growth of 3D nanoscale of MOFs on a 3D network of carbon felt (CF) to enhance the practical applicability of direct ethanol fuel cells (DEFCs) and supercapacitors (SCs). The RuNi-MOF/CF displays remarkable performance for SCs (the high specific capacitance of 1173.7 mF cm−2 (810.8 F g−1) at 6 mA cm−2, a high energy density of 145.9 Wh kg−1 and a power density of 6 kW kg−1 with cyclic retention of 95 %) and as an anode in DEFCs (peak current density of 84.6 mA cm−2 and power density of 70.2 mW cm−2 at 60 °C). The electron/ion transport ability and electrocatalytic performance of RuNi-MOF are enhanced due to the incorporation of Ru about 1.0 %. The success is attributed to the synergistic effects between Ru, Ni, and conductive CF. This work highlights a new understanding of using high-performance materials to improve electrocatalytic activity.

Flattening of a Bent Sulfonated MOF Linker: Impact on Structures, Flexibility, Gas Adsorption, CO2/N2 Selectivity, and Proton Conduction.

Rational design of organic building blocks provides opportunities to control and tune various physicochemical properties of metal-organic frameworks (MOFs), including gas handling, proton conduction, and structural flexibility, the latter of which is responsible for new adsorption phenomena and often superior properties compared to rigid porous materials. In this work, we report synthesis, crystal structures, gas adsorption, and proton conduction for a flexible two-dimensional cadmium-based MOF (JUK-13-SO3H-SO2) containing a new sulfonated 4,4'-oxybis(benzoate) linker with a blocking SO2 bridge. This two-dimensional (2D) MOF is compared in detail with a previously reported three-dimensional Cd-MOF (JUK-13-SO3H), based on analogous, but nonflat, SO2-free sulfonated dicarboxylate. The comprehensive structure-property relationships and the detailed comparisons with insights into the networks flexibility are supported by five guest-dependent structures determined by single-crystal X-ray diffraction (XRD), and corroborated by spectroscopy (IR, 1H NMR), powder XRD, and elemental/thermogravimetric analyses, as well as by volumetric adsorption measurements (for N2, CO2, H2O), ideal adsorbed solution theory (IAST), density-functional theory (DFT+D) quantum chemical and grand-canonical Monte Carlo (GCMC) calculations, and electrochemical impedance spectroscopy (EIS) studies. Whereas both dynamic MOFs show moderate proton conductivity values, they exhibit excellent CO2/N2 selectivity related to the capture of CO2 from flue gases (IAST coefficients for 15:85 mixtures are equal to ca. 250 at 1 bar and 298 K). The presence of terminal sulfonate groups in both MOFs, introduced using a unique prechlorosulfonation strategy, is responsible for their hydrophilicity and water-assisted proton transport ability. The dynamic nature of the MOFs results in the appearance of breathing-type adsorption isotherms that exhibit large hysteresis loops (for CO2 and H2O) attributed to strong host-guest interactions. Theoretical modeling provides information about the adsorption mechanism and supports interpretation of experimental CO2 adsorption isotherms.