Improved Efficiency and Stability of Organic Solar Cells by Interface Modification Using Atomic Layer Deposition of Ultrathin Aluminum Oxide

The interfacial contacts between the electron transporting layers(ETLs)and the photoactive layers are crucial to device performance and stability for OSCs with inverted architecture.Herein,atomic layer deposition(ALD)fabricated ultrathin Al_(2)O_(3)layers are applied to modify the ETLs/active blends(PM6:BTP-BO-4F)interfaces of OSCs,thus improving device performance.The ALD-Al_(2)O_(3)thin layers on ZnO significantly improved its surface morphology,which led to the decreased work function of ZnO and reduced recombination losses in devices.The simultaneous increase in open-circuit voltage(V_(OC)),short-circuit current density(J_(SC))and fill factor(FF)were achieved for the OSCs incorporated with ALD-Al_(2)O_(3)interlayers of a certain thickness,which produced a maximum PCE of 16.61%.Moreover,the ALD-Al_(2)O_(3)interlayers had significantly enhanced device stability by suppressing degradation of the photoactive layers induced by the photocatalytic activity of ZnO and passivating surface defects of ZnO that may play the role of active sites for the adsorption of oxygen and moisture.

Research progress in interface modification and thermal conduction behavior of diamond/metal composites

Diamond/metal composites are widely used in aerospace and electronic packaging fields due to their outstanding high thermal conductivity and low expansion.However,the difference in chemical properties leads to interface incompatibility between diamond and metal,which has a considerable impact on the performance of the composites.To improve the interface compatibility between diamond and metal,it is necessary to modify the interface of composites.This paper reviews the experimental research on interface modification and the application of computational simulation in diamond/metal composites.Combining computational simulation with experimental methods is a promising way to promote diamond/metal composite interface modification research.

Improvement in Performance of Carbon-based Perovskite Solar Cells through Interface Modification with CTAC

Carbon-based perovskite solar cells have attracted much attention,due to their low cost,simple preparation process and high chemical stability.However,the devices exhibit low photoelectric conversion efficiency,owing to the presence of defects and interface impedance between the perovskite active layer and the contact interface.In order to minimize the interfacial defects and improve the charge transfer performance between the perovskite layer and the contact interface,cetyltrimethylammonium chloride(CTAC)was introduced into the lower interface of HTL-free carbon-based perovskite solar cells,because CTAC can be used as interface modification material to passivate the buried interface of perovskite and promote grain growth.It was found that CTAC can not only passivate the interface defects of perovskite,but also improve the crystalline quality of perovskite.As a result,the photovoltaic conversion efficiency of reaches 17.18%,which is 12.5%higher than that of the control group.After 20 days in air with 60%RH humidity,the cell can still maintain more than 90%of the initial efficiency,which provides a new strategy for interfacial passivation of perovskite solar cells.

Skin-inspired interface modification strategy toward a structurefunction integrated hybrid smart fabric system with self-powered sensing property for versatile applications

Fabric-based composites with superior mechanical properties and excellent perceptive function are highly desirable.However,it remains a huge challenge to attain structure-function integration,especially for hybrid fabric composites.Herein,a skin-inspired interface modification strategy is proposed toward this target by constructing a hybrid smart fabric system consisting of two types of smart fabrics:carbon nanotube(CNT)/MXene-modified aramid fabrics and zinc oxide nanorod(ZnO NR)-modified carbon fabrics.Based on that,flexible piezoelectric pressure sensors with skin-like hierarchical perception interfaces are fabricated,which demonstrate superb sensitivity of 2.39 V·kPa^(-1)and are capable of various wearable monitoring tasks.Besides,the interface-modified hybrid fabric reinforced plastics can also be fabricated,which are proven to possess 13.6%higher tensile strength,10.1%elastic modulus.More impressively,their average energy absorption can be improved by 111.9%,accompanied with inherent damage alert capability.This offers a paradigm to fabricate structure-function integrated hybrid smart fabric composites for the smart clothing and intelligent aerial vehicles.

Recent progress of interface modification of layered oxide cathode material for sodium-ion batteries

With the advantages of similar theoretical basis to lithium batteries,relatively low budget and the abundance of sodium resources,sodium ion batteries(SIBs)are recognized as the most competitive alternative to lithium-ion batteries.Among various types of cathodes for SIBs,advan-tages of high theoretical capacity,nontoxic and facile synthesis are introduced for layered transition metal oxide cathodes and therefore they have attracted huge attention.Nevertheless,layered oxide cathodes suffer from various degradation issues.Among these issues,interface instability including surface residues,phase transitions,loss of active transition metal and oxygen loss takes up the major part of the degra-dation of layered oxides.These degradation mechanisms usually lead to irreversible structure collapse and cracking generation,which signifi-cantly influence the interface stability and electrochemical performance of layered cathodes.This review briefly introduces the background of researches on layered cathodes for SIBs and their basic structure types.Then the origins and effects on layered cathodes of degradation mech-anisms are systematically concluded.Finally,we will summarize various interface modification methods including surface engineering,doping modification and electrolyte composition which are aimed to improve interface stability of layered cathodes,perspectives of future research on layered cathodes are mentioned to provide some theoretical proposals.

A facile finger-paint physical modification for bilateral electrode/electrolyte interface towards a stable aqueous Zn battery

Since the electrode/electrolyte interface(EEI)is the main redox center of electrochemical processes,proper manipulation of the EEI microenvironment is crucial to stabilize interfacial behaviors.Here,a finger-paint method is proposed to enable quick physical modification of glass-fiber separator without complicated chemical technology to modulate EEI of bilateral electrodes for aqueous zinc-ion batteries(ZIBs).An elaborate biochar derived from Aspergillus Niger is exploited as the modification agent of EEI,in which the multi-functional groups assist to accelerate Zn^(2+)desolvation and create a hydrophobic environment to homogenize the deposition behavior of Zn anode.Importantly,the finger-paint interface on separator can effectively protect cathodes from abnormal capacity fluctuation and/or rapid attenuation induced by H_(2)O molecular on the interface,which is demonstrated in modified MnO_(2),V_(2)O_(5),and KMn HCF-based cells.The as-proposed finger-paint method opens a new idea of bilateral interface engineering to facilitate the access to the practical application of the stable zinc electrochemistry.

PERFORMANCE ENHANCEMENT OF CdS NANOROD ARRAYS/P3HT HYBRID SOLAR CELLS VIA N719 DYE INTERFACE MODIFICATION

Improved hybrid solar cells consisting of vertical aligned cadmium sulfide （CdS） nanorod arrays and interpenetrating polythiophene （P3HT） have been achieved via modification of CdS nanorod surface by using conjugated N719 dye. The complete infiltration of P3HT between CdS nanorods interspacing was verified by scanning electron microscopy. By employing absorption and photoluminescence spectra, and current-voltage characterization the interaction between N719 molecules and CdS nanorods/P3HT interface was explored, and the role of N719 dye on the improvement of device performance was discussed.

Enhanced photovoltaic performance in TiO_2/P3HT hybrid solar cell by interface modification

A TiO2/P3HT hybrid solar cell was fabricated by infiltrating P3HT into the pores of TiO2 nanorod arrays. To further enhance the photovoltaic performance, anthracene-9-carboxylic acid was employed to modify the interface of TiO2/P3HT before P3HT was coated. Results revealed that the interface treatment significantly enhances the photovoltaic performance of the cell. The efficiency of the hybrid solar cells reaches 0.28% after interface modification, which is three times higher compared with the un-modified one. We find that except for the increased exciton dissociation efficiency recognized by the previous reports, the suppressing of electron back recombination is another important factor leading to the enhanced photovoltaic performance.

Interface issues and challenges for NASICON-based solid-state sodium-metal batteries

All-solid-state sodium(Na)-metal batteries(ASSSMBs)are considered promising candidates for large-scale energy storage systems due to their abundant sodium resources,unparalleled safety performance,and impressive energy density.Na superionic conductors(NASICONs)are among the best enablers of ASSSMBs in view of their high ionic conductivity,ease of synthesis,and excellent thermal stability and good electrochemical/chemical compatibility with common electrodes.However,challenges surrounding the NASICON/electrode interface,such as high interfacial resistance and dendrite formation,have hindered the development of practical ASSSMBs based on NASICONs.This review starts with an explicit summary of the interface problems between the metallic Na anode and NASICON arising from mechanical,chemical,and electrochemical aspects(i.e.,poor interface contact,insulating side-reaction products,and irregular dendrite growth).Subsequently,we systematically analyze and logically categorize modification strategies for addressing anode interface problems and provide a comprehensive discussion on the underlying enhancement mechanisms.As such,we identify underlying and universal interface enhancement mechanisms by comparatively studying various modification strategies.Furthermore,we briefly summarize the challenges in the cathode/electrolyte interface and early-stage research efforts in constructing stable cathode/electrolyte interface and fabricating high-performance composite cathodes.Finally,key suggestions and future prospectives for the advancement of NASICON-based ASSSMBs are outlined.

In situ formed LiF-Li_(3)N interface layer enables ultra-stable sulfide electrolyte-based all-solid-state lithium batteries

Sulfide solid electrolytes are promising for high energy density and safety in all-solid-state batteries due to their high ionic conductivity and good mechanical properties.However,the application of sulfide solid electrolytes in all-solid-state batteries with lithium anode is restricted by the side reactions at lithium/electrolytes interfaces and the growth of lithium dendrite caused by nonuniform lithium deposition.Herein,a homogeneous LiF-Li_(3)N composite protective layer is in situ formed via a manipulated reaction of pentafluorobenzamide with Li metal.The LiF-Li_(3)N layer with both high interfacial energy and interfacial adhesion energy can synergistically suppress side reactions and inhibit the growth of lithium dendrite,achieving uniform deposition of lithium.The critical current densities of Li_(10)GeP_(2)S_(12)and Li_(6)PS_(5)Cl are increased to 3.25 and 1.25 mA cm^(-2)with Li@LiF-Li_(3)N layer,which are almost triple and twice as those of Li-symmetric cells in the absence of protection layer,respectively.Moreover,the Li@LiF-Li_(3)N/Li10GeP2S12/Li@LiF-Li_(3)N cell can stably cycle for 9000 h at 0.1 mA cm^(-2)under 0.1 mA h cm^(-2),and Li@LiF-Li_(3)N/Li_(6)PS_(5)Cl/Li@LiF-Li_(3)N cell achieves stable Li plating/stripping for 8000 h at 0.1 mA cm^(-2)under10 m A h cm^(-2).The improved dynamic stability of lithium plating/stripping in Li@LiF-Li_(3)N/Li_(10)GeP_(2)S_(12)or Li_(6)PS_(5)Cl interfaces is proved by three-electrode cells.As a result,LiCoO_(2)/electrolytes/Li@LiF-Li_(3)N batteries with Li_(10)GeP_(2)S_(12)and Li_(6)PS_(5)Cl exhibit remarkable cycling stability of 500 cycles with capacity retentions of 93.5%and 89.2%at 1 C,respectively.

Improved efficiency and stability of perovskite solar cells with molecular ameliorating of ZnO nanorod/perovskite interface and Mg-doping ZnO

Despite the advanced efficiency of perovskite solar cells(PSCs),electron transportation is still a pending issue.Here the polymer polyvinylpyrrolidone(PVP)is used to enhance the electron injection,which is thanks to the passivation of the defects at the interface between the ZnO electron transporting layer(ETL)and the perovskite.The application of the PVP layer inhibits the device degradation,and 80%of the primary efficiency is kept after 30 d storage in air condition.Additionally,the efficiency of the device is further enhanced by improving the conductivity and crystallinity of the ZnO ETL via Magnesium(Mg)doping in the ZnO nanorods(ZnO NRs).Moreover,the preparation parameters of the ZnO NRs are optimized.By employing the high-crystallinity ZnO ETL and the PVP layer,the power conversion efficiency(PCE)of the champion device is increased from 16.29%to 19.63%.These results demonstrate the advantages of combining mesoscale manipulation with interface modification and doping together.

Fabrication and Modification Strategies of Metal Halide Perovskite Absorbers

Due to the long carrier lifetime,high carrier mobility,and high absorption coefficient of perovskite materials,the power conversion efficiency(PCE)of perovskite solar cells(PSCs)has increased from 3.8%in 2009 to 25.7%in 2021,which have already surpassed the PCE of thin-film solar cells and closes to the efficiency of Si-based photovoltaics(26.7%).Therefore,PSCs have become a promising clean energy technology for commercialization.However,the low defect formation energy of perovskite leads to a higher defect density than other conventional photovoltaic materials.It results in severe non-radiative recombination,limiting its further development and the commercialization.In this review,we summarize the mechanism and strategies for high-quality perovskite absorber fabrications to minimize the bulk and surface/interface defects of halide perovskite,including film quality development and interface modification.Strategies are proposed for further promoting the film quality and the corresponding device performance.Finally,we highlight the challenges that need to be overcome to control over the defect properties of halide perovskite.

Recent advances of interface engineering in inverted perovskite solar cells

Perovskite solar cells(PSCs)have witnessed great achievement in the past decade.Most of previous researches focus on the n-i-p structure of PSCs with ultra-high efficiency.While the n-i-p devices usually used the unstable charge transport layers,such as the hygroscopic doped spiro-OMe TAD,which affect the long-term stability.The inverted device with the p-i-n structure owns better stability when using stable undoped organic molecular or metal oxide materials.There are significant progresses in inverted PSCs,most of them related to charge transport or interface engineering.In this review,we will mainly summarize the inverted PSCs progresses related to the interface engineering.After that,we prospect the future direction on inverted PSCs.

High-Quality van der Waals Epitaxial CsPbBr_(3)Film Grown on Monolayer Graphene Covered TiO_(2)for High-Performance Solar Cells

Two-dimensional materials have been widely used to tune the growth and energy-level alignment of perovskites.However,their incomplete passivation and chaotic usage amounts are not conducive to the preparation of highquality perovskite films.Herein,we succeeded in obtaining higher-quality CsPbBr_(3)films by introducing large-area monolayer graphene as a stable physical overlay on top of TiO_(2)substrates.Benefiting from the inert and atomic smooth graphene surface,the CsPbBr_(3)film grown on top by the van der Waal epitaxy has higher crystallinity,improved(100)orientation,and an average domain size of up to 1.22μm.Meanwhile,a strong downward band bending is observed at the graphene/perovskite interface,improving the electron extraction to the electron transport layers(ETL).As a result,perovskite film grown on graphene has lower photoluminescence(PL)intensity,shorter carrier lifetime,and fewer defects.Finally,a photovoltaic device based on epitaxy CsPbBr_(3)film is fabricated,exhibiting power conversion efficiency(PCE)of up to 10.64%and stability over 2000 h in the air.

Tailoring interphase structure to enable high-rate, durable sodium-ion battery cathode

Na-based layered transition metal oxides with O_(3)-type structure have been considered to be promising cathodes for Na-ion batteries. However, the intrinsically limited Na-ion conductivity induced by the Otype Na-coordinate environment compromises their rate and cycle capability, hindering their practical application. Here, we report an interphase-structure tailoring strategy that improves the electrochemical properties of O_(3)-type layered cathodes achieved through surface coating and doping processes.Specifically, a Zr-doped interphase structure is designed in the model compound NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2) using the ionic conductor Na_(3)Zr_(2)Si_(2)PO_(12) as the surface coating material and Zr-dopant provider. We discover that the modified NaNi_(1/3)Mn_(1/3)Fe_(1/3)O_(2)cathode shows a stable Na-storage structure as well as an enhanced rate/cycle capability. Combined with theoretical calculations, it is suggested that the superior electrochemical performances originate from the Zr-doped interphase structure, which has an enlarged Na layer spacing that forms favorable Na-ion diffusion channels. This work highlights a general material interface optimization method which opens a new perspective for fabricating high-performance electrodes for Na-ion batteries and beyond.

Tuning redox activity through delithiation induced protective layer and Fe-O coordination for Li-rich cathode with improved voltage and cycle performance

Li-rich layered transition metal oxides are one of the most promising cathode materials for their high energy density.However,the cathodes usually suffer from severe potential dropping and capacity fading during cycling,which are associated with the surface oxygen release and accompanied by cation densification and structural collapse.Herein,an integrative approach of simultaneous constructing uniform 3d Fe-ion doping in the transition metal layer and Li-rich Li_(5)FeO_(4) shell to grab the oxygen and prevent interfacial side reactions is proposed.The introduction of Fe induces higher redox potential and stronger 3 d Fe-O_(2)p covalent bond,triggering reversible anionic redox via a reductive coupling mechanism.And the delithiated product of Li-rich Li_(5)FeO_(4) not only acts as a protective layer alleviating the side reactions but also enhances the surface kinetic property.With the benefit of promoted reversibility of oxygen redox and enhanced surface stability,the cathode exhibits high reversible capacity and superior cycle performance.Density function theory calculation indicates that the O_(2)p non-bonding state in the cathode incorporated with Fe sits at a lower energy band,resulting in higher energy storage voltage and improved oxygen stability.Consequently,the modified cathode exhibits a discharge specific capacity of 307 m A h g^(-1)(1 C=250 m A g^(-1)),coulombic efficiency of 82.09%in the initial cycle at 0.1 C and 88.34%capacity retention after 100 cycles at 1 C.The work illustrates a strategy that could simultaneously enhance oxygen redox reversibility and interface stability by constructing lattice bond coordination and delithiation induced protective layer to develop Li-rich materials with high reversible capacity and long lifespan.

Regulation of the photogenerated carrier transfer process during photoelectrochemical water splitting:A review

Photoelectrochemical(PEC)water splitting is considered as an ideal technology to produce hydrogen.Photogenerated carrier migration is one of the most important roles in the whole process of PEC water splitting.It includes bulk transfer inside of the photoelectrode and the exchange at the solid-liquid interface.The energy barriers during the migration process lead to the dramatic recombination of photogenerated hot carrier and the reducing of their redox capacity.Thus,an applied bias voltage should be provided to overcome these energy barriers,which brings the additional loss of energy.Plentiful researches indicate that some methods for the regulation of photogenerated hot carrier,such as p-n junction,unique transfer nanochannel,tandem nanostructure and Z-Scheme transfer structure et al.,show great potential to achieve high-efficient PEC water overall splitting without any applied bias voltage.Up to now,many reviews have summarized and analyzed the methods to enhance the PEC or photocatalysis water splitting from the perspectives of materials,nanostructures and surface modification etc.However,few of them focus on the topic of photogenerated carrier transfer regulation,which is an important and urgent developing technique.For this reason,this review focuses on the regulation of photogenerated carriers generated by the photoelectrodes and summarizes different advanced methods for photogenerated carrier regulation developed in recent years.Some comments and outlooks are also provided at the end of this review.

A Charge Equalizer in Accordion-MXene-Modified Layer Leading to Spherical Lithium Deposition

Lithium-ion batteries with polymer electrolytes(PEs)are promising candidates for high safety performance batteries.However,conventional PEs suffer from poor compatibility and high impedance of electrolyte-electrode interfaces.Herein,we present a method of the interfacial modification for PEs to inhibit lithium dendrites based on the solution to the interfacial compatibility.Our strategy is to improve the interfacial properties and inhibit the dendrite generation by coating a modified layer on PEs of the anode side with acetylene black(AB)and MXene.The mixed conductive layer(MCL)can promote the generation of Li3N and LiF with a uniform arrangement of electrons to form a dense solid electrolyte interphase layer and the even lithium-ion deposition for improving the performance and stability of the battery during cycling.After adding the MCL,the discharge capacity of solid lithium-ion batteries(SLIBs)with lithium bis(trifluoromethanesulfonyl)imide(LiTFSI)/organic modified montmorillonite(OMMT)/soybean isolate protein(SPI)/poly(vinylidene fluoride)(PVDF)(LOSP)PE from 74.2 mAh g^(-1)up to 111.1 mAh g^(-1)(AB-LiTFSI/OMMT/SPI/PVDF(AB-LOSP))and 111.6 mAh g^(-1)(AB/MXene-LiTFSI/OMMT/SPI/PVDF(AB/MXene-LOSP)).The polarization voltage dropped by 0.06 and 0.12 V,respectively.This work represents a milestone in the dendrite-free SLIBs with good performances.

An elastic model for bioinspired design of carbon nanotube bundles

Collagen fibers provide a good example of making strong micro-or mesoscale fibers from nanoscale tropocollagen molecules through a staggered and crosslinked organization in a bottom-up manner.Mimicking the architectural features of collagen fibers has been shown to be a promising approach to develop carbon nanotube（CNT）fibers of high performance.In the present work,an elastic model is developed to describe the load transfer and failure propagation within the bioinspired CNT bundles,and to establish the relations of the mechanical properties of the bundles with a number of geometrical and physical parameters such as the CNT aspect ratio and longitudinal gap,interface cross-link density,and the functionalizationinduced degradation in CNTs,etc.With the model,the stress distributions along the CNT-CNT interface as well as in every individual CNT are well captured,and the failure propagation along the interface and its effects on the mechanical properties of the CNT bundles are predicted.The work may provide useful guidelines for the design of novel CNT fibers in practice.

Anode Interfacial Issues in Solid-State Li Batteries:Mechanistic Understanding and Mitigating Strategies

All-solid-state Li metal batteries(ASSLBs)using inorganic solid electrolyte(SE)are considered promising alternatives to conventional Li-ion batteries,offering improved safety and boosted energy density.While significant progress has been made on improving the ionic conductivity of SEs,the degradation and instability of Li metal/inorganic SE interfaces have become the critical challenges that limit the coulombic efficiency,power performance,and cycling stability of ASSLBs.Understanding the mechanisms of complex/dynamic interfacial phenomena is of great importance in addressing these issues.Herein,recent studies on identifying,understanding,and solving interfacial issues on anode side in ASSLBs are comprehensively reviewed.Typical issues at Li metal/SE interface include Li dendrite growth/propagation,SE cracking,physical contact loss,and electrochemical reactions,which lead to high interfacial resistance and cell failure.The causes of these issues relating to the chemical,physical,and mechanical properties of Li metal and SEs are systematically discussed.Furthermore,effective mitigating strategies are summarized and their effects on suppressing interfacial reactions,improving interfacial Li-ion transport,maintaining interfacial contact,and stabilizing Li plating/stripping are highlighted.The in-depth mechanistic understanding of interfacial issues and complete investigations on current solutions provide foundations and guidance for future research and development to realize practical application of high-performance ASSLB.