Electron Transport Capability Research Articles

Influence of CuO nanoparticles on photosystem II structural stability and functional activity of corn (Zea mays L.) under drought stress

Photoinhibition and photooxidation of photosystem II (PSII) is one of the key damages caused by drought stress. The present study aimed to assess whether or not foliar application of copper oxide nanoparticles (CuO NPs) is effective in promoting PSII stability and activity in corn plants under drought stress. Three-week old plants of corn were subjected to drought stress and varying levels of CuO nano-particles (0, 25, 50, and 100 mM) of the rooting medium. In this study, the effects of foliar application of copper oxide nanoparticles were assessed on growth, plant water status, nutrient uptake and structural stability of photosystem II of drought stressed corn plants. Drought stress impeded overall growth of the corn plants by reducing leaf relative water content, water potential, chlorophyll a content, and accumulation of K+ in plant leaves and roots. Exogenous application of 25 mM CuO NPs significantly enhanced the growth of corn. Exogenous application of CuO NPs improved the dry biomass and length of roots of the corn plants under drought stress. Although the application of nano-particles did not change leaf photosynthetic pigments, relative water content, K+ accumulation, it enhanced the accumulation of K+ in roots. Drought stress did not affect the structural stability of PSII, but it reduced its activity (performance index, PIABS) due to changes in the reaction center density and the biochemical reaction efficiency or electron transport capability. Exogenous application of CuO NPs improved PIABS due to increase in active reaction center density and electron transport efficiency. However, 100 mM CuO NPs application caused PSII damage at the donor end and reduced active reaction center density in the corn plants under both normal and drought stress conditions. The present findings provide a baseline information that foliar application of CuO-nanoparticles in low concentrations can improve the growth of corn by improving accumulation of K+ and increasing PSII activity. Further research is required to explore its effect on cellular redox balance and activities of PSII and PSI, and optimum dose of CuO-nanoparticles for developing formulations for their commercial applications in farmers’ fields.

Voltametric detection of methylene blue dye in water at green and chemically synthesized Ag/MWCNT modified electrode

Abstract A well-known textile dye, methylene blue (MB) was electrochemically detected by using glassy carbon electrode (GCE), modified with green and chemically synthesized silver nanoparticles (AgNPs) decorating the surface of functionalized multiwalled carbon nanotubes (fMWCNT). The green and chemical methods were used to synthesize AgNPs, which decorated MWCNT forming MWCNT/Agchm and MWCNT/Aggrn nanocomposite. Comprehensive characterization of the nanomaterials was carried out using energy-dispersive x-ray spectroscopy (EDX) detector-equipped scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV), and x-ray diffraction (XRD). Using XRD, particle sizes were found to be 26.81, 10.05, 5.36, 19.26, and 17.48 nm for Agchm, Aggrn, MWCNT, Agchm/MWCNT, and Aggrn/MWCNT, respectively. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and square wave voltammetry (SWV) were employed for the investigation of the electrochemical properties and behaviour of MWCNT, Agchm, Aggrn, Agchm/MWCNT, and Aggrn/MWCNT electrodes, and higher electron transport capabilities and improved electrochemical activity towards MB on Agchm/MWCNT electrode were demonstrated by the results. Electroanalysis of methylene blue at the modified electrodes with square wave technique SWV was successful. At Agchm/MWCNT modified electrode, a low limit of detection (LOD) of 4.684 and limit of quantification (LOQ) of 14.194 pM, for MB, while at Aggrn/MWCNT modified electrode , an LOD and LOQ of 2.935 and 8.895 pM, were recorded respectively. In real sample analysis, the recovery percentage for Agchm/MWCNT ranged from 90 to 98% (n =3), and Aggrn/MWCNT showed a recovery percentage ranging from 97 to 103% (n = 3). Both electrodes’ remarkable recovery rate attest to their dependability and sensitivity in MB detection.

One-pot bioinspired synthesis of PbO/CuO/FeO trimetallic oxide nanocomposite using Vitis vinifera fruit juice for highly sensitive electrochemical detection of 4-Nitrotoluene

The determination of explosive nitroaromatic chemicals has prompted concerns about human safety around the world. In this work, we demonstrate an electrochemical sensor based on trimetallic oxide nanocomposites modified screen-printed carbon electrode (SPCE) for the detection of nitroaromatic compounds. Trimetallic oxide nanocomposites are multiphase materials containing ternary metal oxides. Because of their high specific surface area, superior electron transport capabilities, and favourable catalytic behaviour, they are frequently employed as antibacterial materials, catalysts, and sensors. In order to combat the problems associated with high manufacturing costs, low selectivity, and low sensitivity of conventional sensors, this paper reports on the construction of an electrochemical sensor for 4-nitrotoluene (4-NT) using a trimetallic oxide nano-sensor. The nano-sensor is composed of transition metal oxides copper and iron combined with post-transition lead metal oxide. In this study, we prepared a PbO/CuO/FeO TMO NCs sample with different individual metal oxides synthesized by a green reduction method using Vitis vinifera fruit juice. SEM was used to observe and validate structural and morphological variations brought on by various metal compositions. The four bio-synthesized materials comprise dispersed multiphase matrices containing varying shapes of nanoparticles with different morphologies. The elemental and phase arrangements of the synthesized samples were investigated employing UV, FT-IR, XRD, and EDAX approaches. The findings of the electrochemical measurements indicate that the SPCE modified with PbO/CuO/FeO TMO NCs has enhanced sensing capabilities over CuO, FeO, and PbO NPs for 4-NT; the limit of detection is 4.512 nM and sensitivity is −0.531 μA nM−1 for the developed sensor. Notably, recovery values (99.2–101.7 %) in water samples showed that evaluating interfering species from different contaminants had no effect on the sensing of 4-NT. All of these findings show that the newly developed sensor performs well in terms of reproducibility, selectivity, and sensitivity for the detection of 4-NT

Sulfur vacancy synergistically coupling grain cluster for boosting MoS2 piezoresistive properties

MoS2 can be used for piezoresistive sensors because of its excellent mechanical and electrical properties. Herein, MoS2 nanoparticles with sulfur vacancies synergistically coupled with grain clusters to boost piezoresistive properties are fabricated. Moreover, we have demonstrated that they can be regulated efficiently for gauge factor (GF) from 2.97 to 9.99. In particular, the MoS2 nanoparticles with sulfur vacancies of 31.8% and grain cluster of 29.6 nm at the annealing temperature of 500 °C are compatible with synergistic optimization. The abundant sulfur vacancies provide many free electrons as carriers, benefiting the electron transport capability, and the conductive channels formed by the larger grain clusters endow structural stability and significant piezoresistive properties of the nanoparticles. This work demonstrates the promise of MoS2 nanoparticles as novel piezoresistive advanced materials.

Design and fabrication of a novel platform for detection of 5-fluorouracil as the anti-cancer drug using COFs/MOFs nanocomposite with graphene quantum dots

In this study, a novel modified electrode based on the covalent organic frameworks (COFs) Schiff base network-1 (SNW-1) hybridized with copper-based metal–organic frameworks (Cu-MOFs) embedded by graphene quantum dots (GQDs) nanocomposite at the glassy carbon electrode, SNW-1/Cu-MOFs/GQDs/GCE, was reported. The purpose of this modification is to enhance the detection capabilities of the constructed modified electrode for the 5-Fluorouracil (5-FU), an anti-cancer drug, by increasing its electrocatalytic activity towards the oxidation of 5-FU molecules. The SNW-1/Cu-MOFs/GQDs nanocomposite was effectively characterized by the various physicochemical analyses techniques including field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, tunneling electron microscopy, Brunauer-Emmett-Teller (BET), X-ray powder diffraction and electrochemical methods. Electrochemical studies showed that the modified electrode, SNW-1/Cu-MOFs/GQDs/GCE, has better electrocatalytic performance for oxidizing of the 5-FU compared to the unmodified GCE, GQDs/GCE, SNW-1/GCE, Cu-MOFs/GCE and SNW-1/Cu-MOFs/GCE. This enhancement can be attributed to large surface area, good electrical conductivity, enhanced electron transport capability of the SNW-1/Cu-MOFs/GQDs and also synergistic effect of the SNW-1/Cu-MOFs with GQDs. In optimized conditions, the SNW-1/Cu-MOFs/GQDs/GCE sensor demonstrates excellent properties including a wide linear response ranges (0.01–32 and 32–65 μM), low detection limit (35 nM), high sensitivity (3.8 μAμM-1cm2), long-term signal stability, and reproducibility. It is worth noting that this sensor can accurately determine 5-FU in biological sample, showcasing its potential for practical analysis.

Revealing the role of 1T- & 2H- molybdenum Disulfide/Nickel sulfide heterojunction for efficient overall water splitting

In the ongoing quest for cost-effective and durable electrocatalysts for hydrogen production—a critical element of sustainable energy transformation—the 1T phase of Molybdenum Disulfide (MoS2) faces challenges due to its thermodynamic instability and the trade-off between efficiency and durability. Conversely, the 2H phase of MoS2, often disregarded in favor of the metallic 1T phase, suffers from its inert nature and limited active sites. To overcome these limitations, this study employs a straightforward hydrothermal synthesis strategy that couples both 1T and 2H phases of MoS2 with Ni3S2, forming 1T- and 2H- MoS2/Ni3S2 heterojunctions. Enhanced by Ni3S2′s abundant active sites, improved electron transport capabilities, synergistic interface effects, and better structural stability, these heterojunctions achieve a high current density exceeding 500 mA cm−2 at low overpotentials, along with prolonged durability for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline electrolytes. Remarkably, an electrolyzer assembly utilizing 1T-MoS2/Ni3S2 as the cathode and 2H-MoS2/Ni3S2 as the anode demonstrates a competitive voltage of 1.58 V at 20 mA cm−2, showcasing superior performance in overall water splitting compared to other non-noble metal-based electrocatalysts. This study not only offers a viable method for synthesizing efficient and stable electrocatalysts for water splitting using transition metal-based heterogeneous structures but also addresses the fundamental challenges associated with 1T and 2H phases of MoS2.

Facile hydrothermal synthesis of ZnIn2S4/TiO2 nanosheets for promoted hydrogen evolution reaction

The current study was conducted by introducing a narrow bandgap semiconductor, ZnIn2S4, with the goal of addressing the inefficiency of hydrolysis dissociation and the limited visible light absorption capacity faced by TiO2 as a hydrogen evolution reaction (HER) catalyst due to its low conduction band position and wide bandgap. Using a one-step hydrothermal process, ZnIn2S4 nanosheet/TiO2 nanorod heterostructures were built on nickel foam substrates. The nanosheet structure of ZnIn2S4 is shaped like a flower, which greatly increased the roughness of the TiO2 surface and revealed additional active sites. The ZnIn2S4/TiO2 heterostructure demonstrates quick reaction kinetics and effective electron transport capability, as demonstrated by the electrochemical test results. An overpotential of just 195 mV is required to obtain a current density of 10 mA cm−2. In addition, the overpotential is further decreased to 160 mV under simulated solar radiation. Furthermore, ZnIn2S4 addition minimizes the free energy of hydrogen adsorption on the TiO2 surface and optimizes the position of its Fermi energy level, improving the usage of photogenerated carriers, according to density functional theory (DFT) calculations. This work validates the prospective use of ZnIn2S4/TiO2 heterostructures in photoelectrocatalysis and offers a fresh viewpoint for developing high-performance HER catalysts.

Trade-off between sulfidated zero-valent iron reactivity and air stability: Regulation of iron sulfides by ammonium dihydrogen phosphate

The reactivity and stability of zero-valent iron (ZVI) and sulfidated zero-valent iron (S-ZVI) are inherently contradictory. Iron sulfides (FeSX) on the S-ZVI surface play multiple roles, including electrostatic adsorption and catalyzing reduction. We proposed to balance the reactivity and air stability of S-ZVI by regulating FeSX. Benefiting from the superior coordination and accelerate electron transport capabilities of phosphate, herein, eco-friendly ammonium dihydrogen phosphate (ADP) was employed to synthesize N, P, and S-incorporated ZVI (NPS-ZVI) and regulate the FeSX. Raman, FTIR, XPS, and density functional theory (DFT) calculations were combined to reveal that HPO42- acts as the main P species on the Fe surface. The superior reactivity of NPS-ZVI was quantified by kobs, kSA, and kM of Cr(VI), which were 210.77, 27.44, and 211.17-fold than ZVI, respectively. NPS-ZVI demonstrated excellent reusability, with no risk of secondary pollution. Critically, NPS-ZVI could effectively maintain FeSX stability under the combination of diffusion limitation and surface protection mechanisms of ADP. The superior reactivity of NPS-ZVI was attributed to the fact that ADP maintains FeSX stability and accelerates electron transport. This study provides a novel strategy in balancing the reactivity and air stability of S-ZVI and offers theoretical support for material modification.

Hydrophobic Electron‐Transport Layer for Efficient Tin‐Based Perovskite Solar Cells

AbstractWith excellent biocompatibility, a narrow bandgap, and long thermal carrier lifetime, tin‐based perovskite solar cells (TPSCs) are promising within the solar technology. The fullerene derivative indene‐C60 bisadduct (ICBA) is recognized as the most efficient electron‐transport material for TPSCs, thanks to its suitable band structure. Nevertheless, the limited electron transport capability and susceptibility to moisture penetration of ICBA have hindered the progress of TPSCs. Herein, the study proposes a new hydrophobic electron‐transport layer (ETL) comprising a surface‐anchored non‐fullerene n‐type semiconducting polymer layer, poly (naphthalene diimide‐alt‐dithiophenebezothiadiazole) (PNDI‐BT), in conjunction with ICBA. PNDI‐BT exhibits high electron mobilities, a fitting band structure, robust interaction with Sn‐based perovskites, and exceptional moisture resistance, effectively addressing the shortcomings of ICBA. Consequently, this innovative hydrophobic ETL of PNDI‐BT/ICBA enhances electron transport and protects Sn‐based perovskites from moisture. As a result, the inverted TPSCs with the new hydrophobic ETL achieve an impressive efficiency of 13.90%, surpassing TPSCs with the ICBA layer (12.75%). Moreover, even after 1000 h of storage in ambient atmosphere, the encapsulated TPSC maintains a remarkable 81% of its initial efficiency. This comprehensive study seamlessly integrates the synthesis of non‐fullerene n‐type semiconducting polymer and device fabrication, providing valuable insights into designing cutting‐edge ETL structure for inverted TPSCs.

Exploring electron-transfer pathways in co-pyrolyzed waste-derived carbocatalyst for enhanced peroxydisulfate activation

Heterogeneous catalyst-activated peroxydisulfate (PDS) process has great potential in environmental remediation, but its complex preparation process, high cost, low efficiency, and unclear mechanism hinder its practical application. To overcome these limitations, we introduced an innovative metal-free biochar catalyst (SCSS-NC) derived from waste biomass through co-pyrolysis of shrimp shell and sludge with nitrogen doping. This catalyst improved its performance, achieving 78.45 % degradation of tetracycline, outperforming sludge carbon/PDS systems (46.89 %) and shell carbon/PDS systems (22 %) under the dosage of PDS (0.5 mM) and catalysts (0.5 g/L) within 60 min. This improvement stems from its increased surface area, porosity, and electron transport capabilities. Quenching experiments, delayed contaminant addition experiments, and EPR results demonstrated that the SCSS-NC/PDS system relies on electron transfer, in which activated PDS binds to the catalyst surface, forming a highly reactive composite [SCSS-NC/PDS]* to degrade pollutants. The open-circuit potential and linear scanning voltammetry results confirm the existence of an electron transfer pathway, while the situ Raman spectroscopy results validate the presence of the composite [SCSS-NC/PDS]*. The DFT theoretical calculations provide further confirmation of the conductivity, low energy barrier, and ability to expedite electron transfer exhibited by SCSS-NC. The catalyst performance and characterization before, after, and post-recovery from the reaction pinpoint key active sites: pore adsorption, sp2 graphitic carbon, and graphitic nitrogen doping sites. The SCSS-NC/PDS system demonstrates robust anti-interference capability, suggesting its potential for practical organic wastewater treatment. This study provides novel insights into economical carbocatalyst and their mechanisms for environmental applications.

Spectroscopic and antibacterial activities of cobalt and nickel nanoparticles: a comparative analysis

This study aimed to compare the spectroscopy, morphological, electrocatalytic properties, and antibacterial activities of cobalt nanoparticles (CoNPs) with nickel nanoparticles (NiNPs). Cobalt nanoparticles and NiNPs were prepared via a chemical reduction approach and characterized utilizing transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and X-ray diffraction (XRD) techniques. The result from XRD and TEM analysis revealed that the synthesized nanoparticles exhibit face-centered cubic with smooth spherical shape, having average particles size of 12 nm (NiNPs) and 18 nm (CoNPs). The electrochemical properties of the nanoparticles were examined via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The CV results showed that GCE-Ni (35.6 μA) has a higher current response compared to GCE-Co (10.5 μA). The EIS analysis revealed that GCE-Ni (1.39 KΩ) has faster electron transport capability compared to GCE-Co (2.99 KΩ) as indicated in their Rct values. The power density of the synthesized nanoparticles was obtained from their "knee" frequency (f°) values, with GCE-Ni (3.16 Hz) having higher f° values compared to GCE-Co (2.00 Hz). The antibacterial activity of the nanoparticles was evaluated against multidrug-resistant Escherichia coli O157, Escherichia coli O177, Salmonella enterica, Staphylococcus aureus, and Vibrio cholerae. The result from the antibacterial study revealed that at low concentrations both CoNPs and NiNPs have significant antibacterial activities against E. coli O157, E. coli O177, S. enterica, S. aureus, and V. cholerae. NiNPs showed better antibacterial activities at low concentrations of 61.5, 61.5, 125, 61.5, and 125 µg/mL compared to CoNPs with minimum inhibitory concentrations of 125, 125, 250, 61.5, and 125 µg/mL against E. coli O157, E. coli O177, S. enterica, S. aureus, and V. cholerae, respectively. These promising antibacterial activities emphasize the potential of CoNPs and NiNPs as effective antibacterial agents, which could aid in the development of novel antibacterial medicines.

Selenium-Doped Nanoheterojunctions for Highly Efficient Cancer Radiosensitization.

Exploring efficient and low-toxicity radiosensitizers to break through the bottleneck of radiation tolerance, immunosuppression and poor prognosis remains one of the critical developmental challenges in radiotherapy. Nanoheterojunctions, due to their unique physicochemical properties, have demonstrated excellent radiosensitization effects in radiation energy deposition and in lifting tumor radiotherapy inhibition. Herein, they doped selenium (Se) into prussian blue (PB) to construct a nano-heterojunction (Se@PB), which could promote the increase of Fe2+/Fe3+ ratio and conversion of Se to a high valence state with Se introduction. The Fe2+-Se-Fe3+ electron transfer chain accelerates the rate of electron transfer on the surface of the nanoparticles, which in turn endows it with efficient X-ray energy transfer and electron transport capability, and enhances radiotherapy physical sensitivity. Furthermore, Se@PB induces glutathione (GSH) depletion and Fe2+ accumulation through pro-Fenton reaction, thereby disturbs the redox balance in tumor cells and enhances biochemical sensitivity of radiotherapy. As an excellent radiosensitizer, Se@PB effectively enhances X-ray induced mitochondrial dysfunction and DNA damage, thereby promotes cell apoptosis and synergistic cervical cancer radiotherapy. This study elucidates the radiosensitization mechanism of Se-doped nanoheterojunction from the perspective of the electron transfer chain and biochemistry reaction, which provides an efficient and low-toxic strategy in radiotherapy.

3D monolithic composites TiO2/HKUST-1/RGO@melamine foam with improved surface mass transfer for efficient photocatalytic degradation of toluene gas

Currently, photocatalytic technology mostly uses powdered TiO2 catalysts, which are not conducive to recycling, limit the contact between volatile organic compounds (VOCs) and the photocatalyst, and result in lower mass transfer efficiency in gas-solid reactions. Meanwhile, TiO2 catalysts including the electrospun TiO2 nanofibers with hydrophilic surfaces are not favorable for the infiltration and adsorption of non-polar VOCs. To solve these problems, in this work, the monolithic composites TiO2/HKUST-1/RGO@melamine foam (named MRTH) with improved surface mass transfer composed of metal-organic framework (HKUST-1), graphene oxide (GO) and electrospun TiO2 nanofibers was designed. The metal-organic framework HKUST-1 plays a role in promoting the adsorption of toluene, while the reduced graphene oxide (RGO) facilitates the infiltration of non-polar molecules on the surface of the composite and has better electron transport capability. A type II heterojunction between the electrospun TiO2 nanofibers and HKUST-1 formed in the monolithic composites suppresses the recombination of electron-hole pairs and extends their lifespan. Comparing with the bare electrospun TiO2 nanofibers, the MRTH foam composites exhibit a wider light absorption range, hydrophilic and oleophobic properties and a higher separation efficiency of photogenerated carriers. In 90 min of dark adsorption, the removal rate of toluene over MRTH-8 was 52.32 %, while under irradiation by xenon lamp for 150 min, the removal rate over MRTH-8 reached 90.15 %. The amount of monolithic foam composites can also be easily adjusted in the reactor to achieve the best possible removal of the contaminant. The prepared composite materials have been characterized in detail, and the possible mechanisms have also been discussed. The foam composites prepared in this work have high catalytic activity and gas-solid reaction mass transfer efficiency, so they have wide practical application prospects in the field of VOCs abatement.

The synergistic effect of POM-π interaction and solid phase amidation on the visible light photocatalytic of g–C3N4–based photocatalyst

Due to the unique ability of Keggin-type polyoxometalate (POM) to remain stable when accepting electrons to form mixed valence POM, organic-POM hybrid materials can complete multi-electron transfer while maintaining structural stability. The organic-POM hybrids photocatalysts prepared using organic materials and POM as raw materials have been developed to form new energy bands and crystal structures. This not only enhances their quantum efficiency and but also expands their visible light response range. Nevertheless, organic-POM hybrids, featuring organic amines as ligands, are prone to photoetching, impeding g-C3N4's progress in this area. In this paper, the amino group of g-C3N4 was converted into imide ring by solid phase amidation method, which overcame this obstacle and converted g-C3N4 into g-C3N4 based polyimide (CNPI) with enhanced photoelectric properties. XRD, IR spectrum, and XPS data indicate that CNPI is more tightly integrated with potassium phosphotungstate (KPW) than g-C3N4, demonstrating superior electron transport capabilities and potentiated POM-π interactions. In terms of photocatalytic efficacy, CNPI/KPW-30 % exhibits an impressive degradation rate constant of 0.5458 h−1 for imidacloprid, attributed to its compact microstructure and superior charge transfer capability. While maintaining good photocatalytic stability, the mineralization rate of CNPI/KPW-30 % to imidacloprid was 55.25 %. In addition, h+ and ·O2− were identified as active species through trapping agent experiments, and the degradation pathway was advanced by ESR technology analysis.

Ternary organic bulk-heterojunction strategy enables efficient light utilization for perovskite solar cells

Extending the photoresponse into the near-infrared region (NIR) is an urgent research topic in perovskite solar cells. A ternary bulk heterojunction (BHJ) layer composited with PC61BM, D18-Cl and Y6 was deposited onto the perovskite to broaden light absorption. The ternary BHJ layer can absorb low-energy photons in the NIR region (800–920 nm) and generate excitons. Subsequently, these excitons dissociate into free electrons and holes at the donor-acceptor interface, thus extending the device's photo response up to 920 nm. Moreover, due to the good electron transport capabilities of the acceptors Y6 and PC61BM in the BHJ film, the BHJ layer also acts as the electron transport layer in the inverted PSC device. The inverted P–I–N device based on perovskite/BHJ achieved an external quantum efficiency (EQE) up to 30% in the near-infrared range. Compared to control PSCs, the short-circuit current (JSC) increased from 21.64 to 24.35 mA cm−2, resulting in a high PCE of 19.88%. Additionally, the high hydrophobic surface of the ternary layer contributes to the good long-term stability of the device. The results demonstrate that the ternary organic bulk heterojunction is an effective strategy for achieving efficient light utilization in the near-infrared region and enhancing power conversion efficiency in perovskite solar cells.

Electrochemical impedance spectroscopy analysis of dye-sensitized solar cells composed of electrospun composite photoanodes: A comparative study of natural and synthetic sensitizers

In this study, a transmission line model is applied to the electrochemical impedance spectroscopy (EIS) data of the fabricated dye-sensitized solar cells (DSSCs) to evaluate the charge transfer mechanism through the cells. Natural dye from black plum (Syzygium cumini) fruit was used as a cell sensitizer (SC-DSSC) and compared its photovoltaic and electron transport capabilities to those of a cell using a synthetic sensitizer (N719-DSSC). TiO2/ZnO electrospun composite nanofibers were used as the semiconductor layer of the photoanode to enhance electron transfer. The EIS analysis revealed the role of electron resistances through shant, interfaces, and electrolyte solution by measuring the electron transfer kinetic parameters of each element. Based on the results, the SC-DSSC and N719-DSSC are appropriate photovoltaic cells because their ratios of effective electron diffusion length to photoanode thickness are 12.5 and 2.8, respectively. The EIS analysis showed that the electrospun composite nanofiber coated on the photoanode reduces the semiconductor layer's electrical resistance to the cell's total resistance. The extracted natural dye also boosted electron lifetime to 3.68 ms and diffusion coefficient to 54.3×10−6 m2/s while minimizing back-electron recombination at the semiconductor-electrolyte interface. Moreover, the semiconductor-electrolyte interface resistance is over 85% of the overall resistance for both DSSCs and controls electron transport through the cells, which is due to the dye-semiconductor binding intensity. Based on the photovoltaic data, the SC-DSSC cell efficiency was lower than N719-DSSC which is attributed to its higher electron transfer rate-controlling element. Thus, enhancing dye-semiconductor interactions will decrease the rate-controlling impedance and enhance cell performance.

New Electron‐Transporting Materials Based on Pyrimidine and Thiazolopyridine Moieties for High‐Efficiency Organic Light‐Emitting Diodes

Using the pyrimidine moiety with electron‐accepting capability and the thiazolopyridine moiety, commonly used as a moiety with an electron‐withdrawing group in organic semiconductors, for the first time 2‐(3‐(4,6‐di(phenanthren‐9‐yl)pyrimidin‐2‐yl)phenyl)thiazolo[5,4‐b]pyridine (DPPTP) is designed and synthesized to enhance electron transport capabilities compared to the conventional electron‐transporting layer, tris(8‐hydroxyquinoline)aluminum (Alq3). The photoluminescence maxima in solution and film states are observed at 391 and 410 nm, respectively. Although the photoluminescence quantum yield is relatively low at 2% in the solution state, it increases to 28% in the film state. The measured electron mobility values from the fabricated device range from 1.46 × 10−5 to 2.0 × 10−5 cm2 V−1 s−1, ≈5.7 times faster than the electron mobility of Alq3. In a fluorescent blue device utilizing the newly synthesized DPPTP as the electron‐transporting layer, the current efficiency is 4.36 cd A−1, and the external quantum efficiency is 3.76%, representing a 1.3‐fold improvement in efficiency compared to Alq3 devices.

Phosphorus doped magnetic biochar activated PMS for effective degradation of pesticide in water: Targeted regulation of interfacial charge transfer by phosphorus doping

In this study, the incorporation of phosphorus (P) atoms into magnetic biochar was strategically achieved, and the preparation conditions of the composites were optimized by adjusting the pyrolysis temperature and iron doping. The resulting P-doped magnetic biochar (Fe2P@BC-700) exhibited remarkable catalytic activity towards peroxymonosulfate (PMS), rendering it highly effective for the degradation of common organic pesticides, such as 2-Methyl-4-chlorophenoxyacetic acid (MCPA), in aqueous environments. Among them, the apparent rate constant in the oxidation stage was 6.42 times as large as that of magnetic biochar (Fe2BC-700). This was attributed to the fact that the introduced P species tuned the surface electronic configuration of the pristine carbon layer with excellent electron storage and transport capabilities, and the Fe-O-P bonds in the composites acted as electron transport bridges to promote iron cycling in the magnetic nanoparticles during catalysis. The elimination of MCPA in the constructed adsorption enrichment-oxidative degradation system (Fe2P@BC-700/PMS) was achieved through a non-radical pathway dominated by singlet oxygen (1O2) and electron transfer process (ETP). It also ensured broad pH adaptability, environmental stability and repeatability. Density-functional theory calculated that ROS tended to attack the C-Cl branched chain in MCPA and the degradation products showed a tendency of toxicity reduction. This study provided new ideas for the design of market-oriented functional biochar catalysts.

Facilitating Electron Transport in Perovskite Solar Cells Through Tailored SnO2 Film Composition

The ratio of Sn2+ to Sn4+ plays an essential role in influencing the characteristics of SnO2 film, which is commonly used in the normal structure of perovskite solar cells (PSCs). It is identified that different sequences of addition lead to varying concentrations of Sn2+ and Sn4+ within the SnO2 film. Through this strategic approach, an enhanced SnO2 film with improved electron transport capabilities, a smoother surface texture, and more suitable energy levels are successfully engineered. Consequently, the efficiency of PSCs has seen a notable increase from 22.58% for the control device to 24.16% for the target PSC. Furthermore, PSCs utilizing the optimized SnO2 have demonstrated superior long‐term environmental stability when compared to the control devices. Specifically, PSCs incorporating optimized SnO2 expose to approximately 30% humidity in ambient air for 41 days without encapsulation retain 87% of their initial efficiency. In contrast, the control devices under the same conditions only maintain 77% of their original value.

Cu2ZnSnS4/N-MWCNTs hybrid systems as counter electrode substitutes for platinum in dye-sensitized solar cells

Copper zinc tin sulfide, Cu2ZnSnS4 (CZTS) is being considered a viable option for a counter electrode due to its abundance, cost-effectiveness, catalytic activity, and other advantageous properties. However, CZTS has low electron transport capabilities, a shortcoming that can be addressed by combining it with high electron mobility carbon nanomaterials. Nitrogen-doped multi-walled carbon nanotubes (N-MWCNTs) exhibit higher electron conductivities than their pristine counterparts. This improvement is attributed to the disruption of the sp2-hybridized carbon arrangement, as some of the carbon atoms are replaced by nitrogen atoms. In this study, a counter electrode composed of a 70% CZTS and 30% N-MWCNTs mixture produced a higher electrochemical current density compared to the individual materials. This suggests that it is more electrocatalytic than CZTS and N-MWCNTs alone, ultimately leading to the highest power conversion efficiency of 6.52%.Graphical abstract