Recent advances in two-dimensional photovoltaic devices

Two-dimensional(2D)materials have attracted tremendous interest in view of the outstanding optoelectronic properties,showing new possibilities for future photovoltaic devices toward high performance,high specific power and flexibility.In recent years,substantial works have focused on 2D photovoltaic devices,and great progress has been achieved.Here,we present the review of recent advances in 2D photovoltaic devices,focusing on 2D-material-based Schottky junctions,homojunctions,2D−2D heterojunctions,2D−3D heterojunctions,and bulk photovoltaic effect devices.Furthermore,advanced strategies for improving the photovoltaic performances are demonstrated in detail.Finally,conclusions and outlooks are delivered,providing a guideline for the further development of 2D photovoltaic devices.

Intense Intramolecular Charge Transfer Endows Cyanated Polymer with Broad Absorption,Intensified Light-Harvesting,Long-Lived Exciton,and Superior Photovoltaic Property

The donor–acceptor(D–A)copolymers,which exhibit wide broad absorption and intensified light-harvesting,are highly captivating for applications in solar conversion and optoelectronics.However,designing a polymer structure that can achieve these photophysical properties simultaneously remains a challenge.Herein,we report two novel cyanated units 4-cyanobenzo[1,2-b:6,5-b′:3,4-c″]trithiophene(CBT)and 4,6-dicyanobenzo[1,2-b:6,5-b′:3,4-c″]trithiophene(C2BT)and their corresponding polymers,PCBT and PC2BT.Very interestingly,the PC2BT exhibited a broad absorption band with full width at half maxima(FWHM)of its absorption spectra,almost twice wider than PCBT and benchmark polymers PM6 and D18.Moreover,the PC2BT demonstrated intensified light-harvesting and long-lived exciton.Our in-depth investigation unveiled that the presence of dicyano substitutions induced a strong intramolecular charge transfer(ICT),which,in turn,resulted in the formation of favorable photophysical properties.Therefore,PC2BT-based polymer solar cells(PSCs)exhibited an efficiency of 18.06%,which was a record-setting efficiency for cyanated polymers.This study suggests an efficient strategy for enhancing ICT to design polymers toward favorable photophysical properties and excellent photovoltaic performance.

Recent Advances of Imide-Functionalized Polymer Donors for Non-fullerene Solar Cells

In recent years,there has been a shift towards using non-fullerene electron acceptors in organic solar cells(osCs)as a replacement for fullerene derivatives.This change requires polymer donors that possess compatible physical properties,such as absorption range,HoMo energy level,miscibility,and crystallinity.Moreover,the high cost and poor batch-to-batch reproducibility of polymer donors also hinder future large-scale manufacturing.These emphasize the need to explore alternative types of polymer donors.The imide-functionalized building units possess several key attributes that make their polymers highly promising for non-fullerene OsCs.These attributes include ease of synthesis,strong electron-withdrawing ability,rigid and co-planar structure,and the ability to easily tune solubility through imide side chains.In this review,we summarized the synthetic routes of imide building units,and the structural evolution of imide-functionalized polymer donors by focusing on the effects of polymer structure on their physical,optoelectronic,and photovoltaic properties.We hope that this mini-review will serve as a catalyst for future research on imide-functionalized polymers toward high-performance,cost-effective,and durable organic solar cells(oscs).

Humidity-control assists high-efficient coal fly ash removal by PTFE membrane

In the present study,the effects of relative humidity on filtrating coal-fired fly ash with hydrophobic poly tetra fluoroethylene(PTFE) membranes were investigated.The intergranular force of particulate matter at different RH conditions was measured by analyzing the critical angle between particles.Effects of humidity(from 30% to 70%) on filtration pressure drop and membrane fouling conditions were characterized.It was found the membrane showed optimal filtration resistance of 530 Pa at RH of 60% and the gas permeance can be maintained at 1440 m^(3)·m^(-2)·h^(-1)·kPa^(-1).Moreover,to optimize the operation parameters for this filtration system,effects of fly ash concentration,diameter,membrane pore size,and gas velocities were systematically investigated.

Catalytic performance of hybrid Pt@ZnO NRs on carbon fibers for methanol electro-oxidation

A novel Pt@ZnO nanorod/carbon fiber （NR/CF） with hierarchical structure was prepared by atomic layer deposition combined with hydrothermal synthesis and magnetron sputtering （MS）. The morphology of Pt changes from nanoparticle to nanorod bundle with controlled thickness of Pt between 10 and 50 nm. Significantly, with the increase of voltage from 0 to 0.6 V （vs. standard calomel electrode）, the prompt photocurrent generated on ZnO NR/CF increases from 0235 to 0.725 mA. Besides, the Pt@ZnO NR/CF exhibited higher electrochemical active surface area （ECSA） value, better methanol oxidation ability and CO tolerance than Pt@CF, which demonstrated the importance of the multifunctional ZnO support. As the thickness of Pt increasing from 10 to 50 rim, the ECSA values were improved proportionally, leading to the improvement of methanol oxidation ability. More importantly, UV radiation increased the density of peak current of Pt@ZnO NR/CF towards methanol oxidation by additional 42.4%, which may be due to the synergy catalysis of UV light and electricity.

Simulation analysis of municipal solid waste pyrolysis and gasification based on Aspen plus

To predict and analyze the municipal solid waste(MSW)pyrolysis and gasification process in an updraft fixed bed more veritably and appropriately,numerical modeling based on Gibbs energy minimization was executed using the Aspen plus software.The RYield module was combined with the RGibbs module to describe the pyrolysis section,while the RGibbs module was used for the gasification section individually.The proposed model was used to forecast and analyze the target performance parameters including syngas composition,lower heating value(LHV)and carbon conversion rate under different conditions of the gasification temperatures,and ratios and types of gasifying agents.The results indicate that there is a good agreement between the experimental data and the simulated data obtained using this model.The predicted optimum gasification temperature is approximately 750°C,and the best ratio of water vapor as gasifying agent is around 0.4.The mixture of flue gas and water vapor has an economical and recycled prospect among four commonly used gasifying agents.

Effect of mechanical stretching and substrate stiffness on the morphology,cytoskeleton and nuclear shape of corneal endothelial cells

Due to the limited capacity of corneal endothelial cells(CECs)division,corneal endothelial diseases have become a great challenge.The cornea is subjected to various mechanical stimuli in vivo,which may have a positive or negative influence.Thus,it is significant to gain an insight into the mechanism of mechanobiology of CECs for seeking more possible treatment.The purpose of this study was to determine the impacts of mechanical stretch and substrate stiffness on the morphology and fundamental cell behavior of CECs.Rabbit corneal endothelial cells(RCECs)were subjected to a 5%mechanical stretch or cultured on substrates of different stiffness.The impacts of mechanical stimulus on cell area,aspect ratio,circularity,cell density,nuclear shape,cytoskeleton,and cell viability were investigated.The expressions of the corneal endothelium-related markers ZO-1 and Na^(+)/K^(+) ATPase were also evaluated by confocal immunofluorescence microscopy in the stiffness group.Our results suggested that mechanical stretch promoted the rearrangement of the cytoskeleton while decreasing the cell circularity,nuclear area,and cell density as well as cell viability.RCECs cultured on 10 kPa substrates,which was close to the physiological stiffness of rabbit Descemet's membrane(DM),showed better cell morphology,more stable actin cytoskeleton assembly,and more robust expression of the functional marker compared with other softer or stiffer substrates.In summary,mechanical stretch and substrate stiffness have profound influences on the morphology and function of CECs,which may have implications for the understanding and possible treatment of corneal endothelial diseases.

具有亚2-nm沟道长度的二维垂直p-n结二极管

尺寸极限微缩的p-n结二极管对互补金属氧化物半导体(CMOS)集成电路的发展至关重要.然而,由于界面缺陷和短沟道效应,实现5 nm以下沟道长度的p-n结二极管仍然面临着巨大的挑战.本文展示了1.9 nm沟道的WSe_(2)/WS_(2)垂直p-n结二极管,实现了~8×10^(3)的高开关比和~17的整流比.此外,沟道长度为4.7 nm的器件具有~10^(4)的高开关比和~10^(3)的整流比.其高性能源于无肖特基势垒的接触导致的理想带排列,以及无缺陷的全范德华(vdW)界面导致的低隧穿电流和小的费米钉扎效应.因此,我们实现了p-n二极管的本征性能.该策略也可以扩展到其他的p-n结,如WSe_(2)/MoSe_(2)和WSe_(2)/MoS_(2),这表明我们的策略具有普适性.该策略为电子器件尺寸微缩和集成电路的进一步发展提供了新的思路.

Design and synthesis of porous non-noble metal oxides for catalytic removal of VOCs

The design and synthesis of highly active non-noble metal oxide catalysts, such as transition- and rare-earth-metal oxides, have attracted significant attention because of their high efficiency and low cost and the resultant potential applications for the degradation of volatile organic compounds(VOCs). The structure-activity relationships have been well-studied and used to facilitate design of the structure and composition of highly active catalysts. Recently, non-noble metal oxides with porous structures have been used as catalysts for deep oxidation of VOCs, such as aromatic hydrocarbons, aliphatic compounds, aldehydes, and alcohols, with comparable activities to their noble metal counterparts. This review summarizes the growing literature regarding the use of porous metal oxides for the catalytic removal of VOCs, with emphasis on design of the composition and structure and typical synthetic technologies.

Large-scale synthesis of hierarchical MnO_2 for benzene catalytic oxidation

Hierarchical sea-urchin-shaped manganese oxide microspheres were synthesized via a facile method based on the reaction between KMnO4 and MnSO4 in HNO3 solution at 50℃. The average diameter of the microspheres is -850 nm. The microspheres consist of a core of diameter of -800 nm and nanorods of width -50 nm. The nanorods exist at the edge of the core, The Brunauer-Emmett-Teller surface area of the sea-urchin-shaped microspheres is 259.4 m^2/g. A possible formation mechanism of the hierarchical sea-urchin-shaped microspheres is proposed. The temperature for 90% conversion of benzene （T90%） on the hierarchical urchin-shaped MnO2 microspheres is about 218 ℃.