Asymmetric Coordination of Bimetallic Fe-Co Single-Atom Pairs toward Enhanced Bifunctional Activity for Rechargeable Zinc-Air Batteries.

The advancement of rechargeable zinc-air batteries (RZABs) faces challenges from the pronounced polarization and sluggish kinetics of oxygen reduction and evolution reactions (ORR and OER). Single-atom catalysts offer an effective solution, yet their insufficient or singular catalytic activity hinders their development. In this work, a dual single-atom catalyst, FeCo-SAs, was fabricated, featuring atomically dispersed N3-Fe-Co-N4 sites on N-doped graphene nanosheets for bifunctional activity. Introducing Co into Fe single-atoms and secondary pyrolysis altered Fe coordination with N, creating an asymmetric environment that promoted charge transfer and increased the density of states near the Fermi level. This catalyst achieved a narrow potential gap of 0.616 V, with a half-wave potential of 0.884 V for ORR (vs the reversible hydrogen electrode) and a low OER overpotential of 270 mV at 10 mA cm-2. Owing to the superior activity of FeCo-SAs, RZABs exhibited a peak power density of 203.36 mW cm-2 and an extended cycle life of over 550 h, exceeding the commercial Pt/C + IrO2 catalyst. Furthermore, flexible RZABs with FeCo-SAs demonstrated the promising future of bimetallic pairs in wearable energy storage devices.

Aqueous synthesis of perovskite precursors for highly efficient perovskite solar cells.

High-purity precursor materials are vital for high-efficiency perovskite solar cells (PSCs) to reduce defect density caused by impurities in perovskite. In this study, we present aqueous synthesized perovskite microcrystals as precursor materials for PSCs. Our approach enables kilogram-scale mass production and synthesizes formamidinium lead iodide (FAPbI3) microcrystals with up to 99.996% purity, with an average value of 99.994 ± 0.0015%, from inexpensive, low-purity raw materials. The reduction in calcium ions, which made up the largest impurity in the aqueous solution, led to the greatest reduction in carrier trap states, and its deliberate introduction was shown to decrease device performance. With these purified precursors, we achieved a power conversion efficiency (PCE) of 25.6% (25.3% certified) in inverted PSCs and retained 94% of the initial PCE after 1000 hours of continuous simulated solar illumination at 50°C.

FeP-Fe3O4 nanospheres for electrocatalytic N2 reduction to NH3 under ambient conditions.

The electrocatalytic nitrogen reduction reaction (eNRR) under ambient conditions is deemed a promising alternative for NH3 synthesis. In this paper, an FeP-Fe3O4 nanocomposite electrocatalyst was prepared by phosphating annealing using Fe2O3 as a precursor, and the resulting FeP-Fe3O4 exhibited excellent N2-to-NH3-producing activity over a wide potential window. The highest faradaic efficiency of FeP-Fe3O4 is 11.02% at -0.1 V vs. reversible hydrogen electrode (RHE), and the maximum NH3 yield reaches 12.73 µg h-1 mgcat-1, comparable to or exceeding the reported values in this field. Furthermore, the FeP-Fe3O4 nanocomposite electrocatalyst presents high electrochemical stability, selectivity, and durability.

A multi-layer reduced graphene oxide catalyst encapsulating a high-entropy alloy for rechargeable zinc-air batteries.

A reduced graphene oxide encapsulating Fe6Ni20Co2Mn2Cu1.5@rGO catalyst is prepared using a Joule heating strategy. The graphene-coated layer with high crystallinity enhances the stability of the crystal structure, resulting in superior OER activity. Rechargeable zinc-air batteries with Fe6Ni20Co2Mn2Cu1.5@rGO demonstrate remarkable performance, boasting a high specific capacity of 800 mA h gZn-1, an impressive peak power density of 154.612 mW cm-2, and a cycle life of 300 hours at a current density of 10 mA cm-2.

Organic Photovoltaic Stability: Understanding the Role of Engineering Exciton and Charge Carrier Dynamics from Recent Progress.

Benefiting from the synergistic development of material design, device engineering, and the mechanistic understanding of device physics, the certified power conversion efficiencies (PCEs) of single-junction non-fullerene organic solar cells (OSCs) have already reached a very high value of exceeding 19%. However, in addition to PCEs, the poor stability is now a challenging obstacle for commercial applications of organic photovoltaics (OPVs). Herein, recent progress made in exploring operational mechanisms, anomalous photoelectric behaviors, and improving long-term stability in non-fullerene OSCs are highlighted from a novel and previously largely undiscussed perspective of engineering exciton and charge carrier pathways. Considering the intrinsic connection among multiple temporal-scale photocarrier dynamics, multi-length scale morphologies, and photovoltaic performance in OPVs, this review delineates and establishes a comprehensive and in-depth property-function relationship for evaluating the actual device stability. Moreover, this review has also provided some valuable photophysical insights into employing the advanced characterization techniques such as transient absorption spectroscopy and time-resolved fluorescence imagings. Finally, some of the remaining major challenges related to this topic are proposed toward the further advances of enhancing long-term operational stability in non-fullerene OSCs.

Solubility Measurement and Correlation of Itraconazole Hydroxy Isobutyltriazolone in Four Kinds of Binary Solvent Mixtures with Temperature from 283.15 to 323.15 K.

The solubility of itraconazole hydroxy isobutyltriazolone (IHI) in four commonly used binary solvent mixtures of N,N-dimethylformamide (DMF) + water, DMF + ethanol, tetrahydrofuran (THF) + water, and THF + ethanol was determined with gravimetric method at temperatures ranging from 283.15 to 323.15 K under atmospheric pressure. The solubility of IHI in all selected solvents increases with the increase of temperature. The maximum solubility of IHI exists in the solvent of DMF + ethanol (0.06523 mol·mol-1, x20 = 0.7, T = 323.15 K), while the minimum solubility exists in DMF + water (0.0003723 mol·mol-1, x20 = 0.3, T = 283.15 K). There is a co-solvency phenomenon in the mixed solvents of DMF+ ethanol, THF + water, and THF + ethanol. Four thermodynamic models, including the modified Apelblat model, the Yaws model, the Sun model, and the modified Jouyban-Acree model, were selected to fit the solubility data of IHI. All the RAD values are less than 0.0484, and RMSD values are not more than 0.001319. The Yaws model and the modified Apelblat model fit the solubility data of IHI better than the other two models. All the selected four models can fit the solubility data of IHI well.

The Formation Mechanism of (001) Facet Dominated α-FAPbI3 Film by Pseudohalide Ions for High-Performance Perovskite Solar Cells.

Formamidinium lead triiodide (α-FAPbI3 ) has been widely used in high-efficiency perovskite solar cells due to its small band gap and excellent charge-transport properties. Recently, some additives show facet selectivity to generate a (001) facet-dominant film during crystallization. However, the mechanism to realize such (001) facet selectivity is not fully understood. Here, the authors attempted to use three ammonia salts NH4 X (X are pseudohalide anions) to achieve better (001) facet selectivity in perovskite crystallization and improved crystallinity. After addition, the (001) facet dominance is generally increased with the best effect from SCN- anions. The theoretical calculation revealed three mechanisms of such improvements. First, pseudohalide anions have larger binding energy than the iodine ion to bind the facets including (110), (210), and (111), slowing down the growth of these facets. The large binding energy also reduces nucleation density and improves crystallinity. Second, pseudohalide ions improve phase purity by increasing the formation energies of the δ-phase and other hexagonal polytypes, retarding the α- to δ-phase transition. Third, the strong binding of these anions can also effectively passivate the iodine vacancies and suppress nonradiative recombination. As a result, the devices show a power conversion efficiency of 24.11% with a Voc of 1.181 V.

Solid-State Nanopore/Nanochannel Sensing of Single Entities.

Solid-state nanopores/nanochannels, with their high stability, tunable geometry, and controllable surface chemistry, have recently become an important tool for constructing biosensors. Compared with traditional biosensors, biosensors constructed with solid-state nanopores/nanochannels exhibit significant advantages of high sensitivity, high specificity, and high spatiotemporal resolution in the detection single entities (such as single molecules, single particles, and single cells) due to their unique nanoconfined space-induced target enrichment effect. Generally, the solid-state nanopore/nanochannel modification method is the inner wall modification, and the detection principles are the resistive pulse method and the steady-state ion current method. During the detection process, solid-state nanopore/nanochannel is easily blocked by single entities, and interfering substances easily enter the solid-state nanopore/nanochannel to generate interference signals, resulting in inaccurate measurement results. In addition, the problem of low flux in the detection process of solid-state nanopore/nanochannel, these defects limit the application of solid-state nanopore/nanochannel. In this review, we introduce the preparation and functionalization of solid-state nanopore/nanochannel, the research progress in the field of single entities sensing, and the novel sensing strategies on solving the above problems in solid-state nanopore/nanochannel single-entity sensing. At the same time, the challenges and prospects of solid-state nanopore/nanochannel for single-entity electrochemical sensing are also discussed.

Dual Optimization of Bulk and Interface via the Synergistic Effect of Ligand Anchoring and Hole Transport Dopant Enables 23.28% Efficiency Inverted Perovskite Solar Cells.

The crystalline morphology of perovskite film plays a key role in determining the stability and performance of perovskite solar cells (PSCs). In addition, the work function and conductivity of hole transport layer (HTL) have a great influence on the effciency of PSCs. Here, we develop a synergistic doping strategy to fabricate high-performance inverted PSCs, doping a functional nanographene (C78-AHM) into the poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA) HTL, thus forming an HTL with higher conductivity, lower roughness, and frontier energy levels matching the perovskite absorber work function. On this basis, thiosemicarbazide (TSC) was doped into the precursor solution of perovskite as the grain and interface modifier to further improve the crystalline morphology of perovskite film. Compared with the current single passivation method, this codoping strategy can simultaneously reduce the surface and bulk defects of perovskite film and reduce the interface energy barrier. Eventually, high-quality TSC-doped perovskite films based on C78-AHM-doped PTAA HTL are obtained with over 2 µm sized grains, pinhole-free, and improved crystallinity. As a result, this synergistic doping strategy increases the efficiency of the device from 20.27% to 23.28%. Furthermore, the environmental and thermal stabilities of the devices are significantly improved. Therefore, this work provides a simple way for the preparation of other efficient optoelectronic devices.

Tuning Perovskite Surface Polarity via Dipole Moment Engineering for Efficient Hole-Transport-Layer-Free Sn-Pb Mixed-Perovskite Solar Cells.

Post-treatment has been recognized as one of the effective methods for passivating the underlying defects in perovskite solar cells (PSCs), but little attention has been paid to how to pick suitable passivation agents with diverse isomers for efficient PSCs, particularly for the tin-lead (Sn-Pb) mixed PSCs. Here, we introduce the dependence of the power conversion efficiency (PCE) on a dipole moment for surface passivator screening, in which we chose three trifluoromethyl-phenylethylamine hydroiodide (CF3-PEAI) isomers as surface-treatment materials for hole-transport-layer-free (HTL-free) Sn-Pb mixed PSCs. The different positions of the -CF3 group for the CF3-PEAI isomer result in different dipole moments, which influences the interaction between CF3-PEAI and lead iodide. The para position CF3 with the highest dipole moment exhibits a higher PCE than the ortho-position with a lower dipole moment, which is attributed to the large dipole moment on the surface that could tune the surface polarity from p-type to n-type, facilitating electron charge transport in the HTL-free Sn-Pb mixed PSCs. An ultrathin 2D layer is formed on the perovskite surface to passivate the surface defects, which is responsible for the enhancement of the PCE and stability of the PSCs. As a result, the open-circuit voltage (VOC) of the device is improved from 0.775 to 0.824 V, yielding a champion PCE of 20.17%, which is one of the highest PCEs among the reported HTL-free Sn-Pb mixed PSCs. The device also shows improved stability with remaining 75% of its initial PCEs after storage in N2 for 700 h.

Correlating Charge Transfer Dynamics with Interfacial Trap States in High-Efficiency Organic Solar Cells.

The charge transfer between the donor and acceptor determines the photogenerated carrier density in organic solar cells. However, a fundamental understanding regarding the charge transfer at donor/acceptor interfaces with high-density traps has not been fully addressed. Herein, a general correlation between trap densities and charge transfer dynamics is established by adopting a series of high-efficiency organic photovoltaic blends. It is found that the electron transfer rates are reduced with increased trap densities, while the hole transfer rates are independent of trap states. The local charges captured by traps can induce potential barrier formation around recombination centers, leading to the suppression of electron transfer. For the hole transfer process, the thermal energy provides a sufficient driving force, which ensures an efficient transfer rate. As a result, a 17.18% efficiency is obtained for PM6:BTP-eC9-based devices with the lowest interfacial trap densities. This work highlights the importance of interfacial traps in charge transfer processes and proposes an underlying insight into the charge transfer mechanism at nonideal interfaces in organic heterostructures.

Robust Iris-Localization Algorithm in Non-Cooperative Environments Based on the Improved YOLO v4 Model.

Iris localization in non-cooperative environments is challenging and essential for accurate iris recognition. Motivated by the traditional iris-localization algorithm and the robustness of the YOLO model, we propose a novel iris-localization algorithm. First, we design a novel iris detector with a modified you only look once v4 (YOLO v4) model. We can approximate the position of the pupil center. Then, we use a modified integro-differential operator to precisely locate the iris inner and outer boundaries. Experiment results show that iris-detection accuracy can reach 99.83% with this modified YOLO v4 model, which is higher than that of a traditional YOLO v4 model. The accuracy in locating the inner and outer boundary of the iris without glasses can reach 97.72% at a short distance and 98.32% at a long distance. The locating accuracy with glasses can obtained at 93.91% and 84%, respectively. It is much higher than the traditional Daugman's algorithm. Extensive experiments conducted on multiple datasets demonstrate the effectiveness and robustness of our method for iris localization in non-cooperative environments.

Dually Modified Wide-Bandgap Perovskites by Phenylethylammonium Acetate toward Highly Efficient Solar Cells with Low Photovoltage Loss.

Wide-bandgap perovskites as a class of promising top-cell materials have shown great promise in constructing efficient perovskite-based tandem solar cells, but their intrinsic relatively low radiative efficiency results in a large open-circuit voltage (VOC) deficit and thereby limits the whole device performance. Reducing film flaws or optimizing interfacial energy level alignments in wide-bandgap perovskite devices can efficiently inhibit nonradiative recombination to boost device VOC and efficiency. However, the simultaneous regulation on both sides and their underlying mechanism are less explored. Herein, a bifunctional modification approach is proposed to optimize the wide-bandgap perovskite surface with an ultrathin layer of phenylethylammonium acetate (PEAAc) to synchronously decrease the surface imperfection and mitigate the interfacial energy barrier. This treatment effectively heals under-coordinated surface defects through the formation of chemical interaction between the perovskite and PEAAc, bringing about a much slower charge trapping process and dramatically decreasing nonradiative recombination losses. Meanwhile, the passivation-induced upshifted Fermi level of the perovskite contributes to accelerated electron extraction and larger Fermi-level splitting under illumination. Consequently, the PEAAc-modified wide-bandgap (1.68 eV) device achieves an optimal efficiency of 20.66% with a high VOC of 1.25 V, among the highest reported VOC values for wide-bandgap perovskite devices, enormously outperforming that (18.86% and 1.18 V) of the device without passivation. In addition, the radiative limit of VOC for both cells is determined to be 1.42 V, delivering nonradiative recombination losses of 0.24 and 0.17 V for the control and PEAAc-modified devices, respectively. These results highlight the significance of the bifunctional modification strategy in achieving high-performance wide-bandgap perovskite devices.

Integrated Ideal-Bandgap Perovskite/Bulk-Heterojunction Solar Cells with Efficiencies > 24.

Here, the authors report a highly efficient integrated ideal-bandgap perovskite/bulk-heterojunction solar cell (IPBSC) with an inverted architecture, featuring a near infrared (NIR) polymer DTBTI-based bulk-heterojunction (BHJ) layer atop guanidinium bromide (GABr)-modified FA0.7 MA0.3 Pb0.7 Sn0.3 I3 perovskite film as the photoactive layer. The IPBSC shows cascade-like energy level alignment between the charge-extractionlayer/perovskite/BHJ and efficient passivation effect of BHJ on perovskite. Thanks to the well-matched energy level alignment and high-quality ideal bandgap-based perovskite film, an efficient charge transfer occurs between the charge-extraction-layer/perovskite/BHJ. Moreover, the NIR polymer DTBTI on the perovskite film leads to an improved NIR light response for the IPBSC. In addition, the O, S and N atoms in the DTBTI polymer yield a strong interaction with perovskite, which is conducive to reducing the defects of the perovskite and suppressing charge recombination. As a result, the solar cell achieves a power conversion efficiency (PCE) of 24.27% (certificated value at 23.4% with 0.283-volt voltage loss), currently the recorded efficiency for both IPBSCs and Pb-Sn alloyed PSCs, and which is over the highest efficiency of perovskite-organic tandem solar cell. Moreover, the thermal, humidity and long-term operational stabilities of the IPBSCs are also significantly improved compared with the control PSCs.

In situ fabrication of dry/gel bilayer Ti3C2Tx films for high-rate micro-supercapacitors.

A H2SO4-Ti3C2Tx ion-gel is in situ fabricated to prevent the restacking of Ti3C2Tx for high-rate micro-supercapacitors. The ion-gel pillared by an electrolyte possesses an enlarged interlayer spacing facilitating ion transport. Furthermore, a bilayer structure is designed with dry Ti3C2Tx for fast electron conduction. The bilayer Ti3C2Tx film shows improved capacitance from 49% to 73% of the initial capacitance at a high scan rate of 200 mV s-1, along with excellent cycle stability. This study opens up a concise and efficient way for high-performance micro-supercapacitors.

Highly Orientational Order Perovskite Induced by In situ-generated 1D Perovskitoid for Efficient and Stable Printable Photovoltaics.

Employing low-dimensional perovskite has been proven to be a promising approach to enhance the efficiency and stability of perovskite solar cells. Here, thiopheniformamidine hydrochloride is introduced into CH3 NH3 PbI3 -based printable mesoscopic perovskite solar cells, to form 1D iodide lead thiophenamidine (TFPbI3 ) in situ. This judiciously designed low-dimensional perovskite can effectively passivate the defect of perovskite and induce the perovskite crystals to grow in a direction perpendicular to the substrate. Thus, the obtained 1D@3D perovskite could suppress the charge recombination and promote the charge transfer significantly. Benefiting from its dual effect and robustness, a significantly improved power conversion efficiency of 17.42% is yielded. The authors also develop high-performance printable mesoscopic perovskite solar cells with a champion efficiency approaching 13% for aperture area about 11.8 cm2 , as well as outstanding operational stability, retaining 90% of the original power conversion efficiency after 1000 hours of continuous illumination at the maximum power point in air.

Effects of Side-Chain Engineering with the S Atom in Thieno[3,2-b]thiophene-porphyrin to Obtain Small-Molecule Donor Materials for Organic Solar Cells.

To explore the effect of the introduction of heteroatoms on the properties of porphyrin materials, a new porphyrin-based derivative small-molecule donor named as PorTT-T was designed and synthesized based on alkyl-thieno[3,2-b]thiophene(TT)-substituted porphyrins. The linker bridge and end groups of PorTT-T were the same as those of XLP-II small-molecule donor materials, while the side-chain attached to the core of thieno[3,2-b]thiophene(TT)-substituted porphyrin was different. Measurements of intrinsic properties showed that PorTT-T has wide absorption and appropriate energy levels in the UV-visible range. A comparison of the morphologies of the two materials using atomic force microscopy showed that PorTT-T has a better surface morphology with a smaller root-mean-square roughness, and can present closer intermolecular stacking as compared to XLP-II. The device characterization results showed that PorTT-T with the introduced S atom has a higher open circuit voltage of 0.886 eV, a higher short circuit current of 12.03 mAcm-2, a fill factor of 0.499, a high photovoltaic conversion efficiency of 5.32%, better external quantum efficiency in the UV-visible range, and higher hole mobility.

Water-Soluble Conjugated Polyelectrolyte Hole Transporting Layer for Efficient Sky-Blue Perovskite Light-Emitting Diodes.

An optimized charge transporting layer (CTL) under perovskite film is crucial for efficient photoelectric devices. Here, a new water-soluble conjugated polyeletrolyte (CPE) with CH3 NH3 + (MA+ ) counterion termed as TB(MA) is used as the hole transporting layer (HTL) instead of the acidic poly(3,4-ethylenedioxythiophene):poly-styrene sulfonate (PEDOT:PSS) in sky-blue perovskite light-emitting diodes (PeLEDs). The inherent hydrophilicity of CPE enables a well-growth of quasi-2D perovskite layer with uniform and compact morphology, enhanced crystallinity with rare defect density and excellent energy transfer, resulting in a high photoluminescence quantum yield (PLQY) up to 62.0%. Especially, the MA+ counterion is able to passivate the interfacial defects in the perovskite, which optimize the interfacial compatibility between HTL and perovskite film. Finally, efficient sky-blue PeLEDs, emitting at 488 nm, are fabricated with high external quantum efficiency (EQE) up to 13.5% by using CPE as HTL. In addition, due to the low-temperature processability of water-soluble CPE, an efficient flexible sky-blue PeLEDs based on PEN/ITO substrate is also obtained with high EQE of 8.3%. Using CPE as HTL is an effective strategy toward fabricating efficient blue PeLEDs.

Evaluation of an intermittent-aeration constructed wetland for removing residual organics and nutrients from secondary effluent: Performance and microbial analysis.

This study proposed a novel intermittent-aeration constructed wetland (CW) to resolve the vertical loss of oxygen in tertiary treatment. Compared to the non-aeration CW, the intermittent-aeration CW presented a better removal performance (90.8% chemical oxygen demand, 94.3% ammonia nitrogen, 91.5% total nitrogen and 94.1% total phosphorus) at a dissolved oxygen of 3 mg L-1 and hydraulic retention time of 2 days. It was mainly attributed to the higher abundance and greater diversity of bacterial community due to the oxygen supply. High-throughput sequencing indicated that high abundance of phyla Proteobacteria (35.34%) and Bacteroidetes (18.20%) in intermittent-aeration CW were responsible for simultaneous nitrogen and phosphorus removal. Besides, the dominant families Burkholderiaceae (11.16%), Microtrichales (6.88%) and Saprospiraceae (6.50%) were also detected, which was vital to hydrolyze and utilize complex organic matters. In general, oxygen supply upregulated the metabolism pathways of amino acid and carbohydrate, bringing a greater biodegradation potential for removing contaminants.

An in-situ defect passivation through a green anti-solvent approach for high-efficiency and stable perovskite solar cells.

Surface and grain boundary defects in halide perovskite solar cells are highly detrimental, reducing efficiencies and stabilities. Widespread halide anion and organic cation defects usually aggravate ion diffusion and material degradation on the surfaces and at the grain boundaries of perovskite films. In this study, we employ an in-situ green method utilizing nontoxic cetyltrimethylammonium chloride (CTAC) and isopropanol (IPA) as anti-solvents to effectively passivate both surface and grain boundary defects in hybrid perovskites. Anion vacancies can be readily passivated by the chloride group due to its high electronegativity, and cation defects can be synchronously passivated by the more stable cetyltrimethylammonium group. The results show that the charge trap density was significantly reduced, while the carrier recombination lifetime was markedly extended. As a result, the power conversion efficiency of the cell can reach 23.4% with this in-situ green method. In addition, the device retains 85% of its original power conversion efficiency after 600 h of operation under illumination, showing that the stability of perovskite solar cells is improved with this in-situ passivation strategy. This work may provide a green and effective route to improve both the stability and efficiency of perovskite solar cells.