Electrochemically Deposited CZTSSe Thin Films for Monolithic Perovskite Tandem Solar Cells with Efficiencies Over 17%

In spite of the high potential economic feasibility of the tandem solar cells consisting of the halide perovskite and the kesterite Cu2ZnSn(S,Se)4(CZTSSe),they have rarely been demonstrated due to the difficulty in implementing solution-processed perovskite top cell on the rough surface of the bottom cells.Here,we firstly demonstrate an efficient monolithic two-terminal perovskite/CZTSSe tandem solar cell by significantly reducing the surface roughness of the electrochemically deposited CZTSSe bottom cell.The surface roughness(R_(rms))of the CZTSSe thin film could be reduced from 424 to 86 nm by using the potentiostatic mode rather than using the conventional galvanostatic mode,which can be further reduced to 22 nm after the subsequent ion-milling process.The perovskite top cell with a bandgap of 1.65 eV could be prepared using a solution process on the flattened CZTSSe bottom cell,resulting in the efficient perovskite/CZTSSe tandem solar cells.After the current matching between two subcells involving the thickness control of the perovskite layer,the best performing tandem device exhibited a high conversion efficiency of 17.5%without the hysteresis effect.

Experimental verification of nanonization enhanced solubility for poorly soluble optoelectronic molecules

Solubility enhancement has been a priority to overcome poor solubility with optoelectronic molecules for solution-processable devices. This study aims to obtain experimental data on the effect of particle sizes on the solubility properties of several typical optoelectronic molecules in organic solvents, including the solubility results of 1,3-bis(9-carbazolyl)benzene(m CP), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)ben zene(TPBi) and 2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole(PBD) in ethanol and acetonitrile,respectively. Nanoparticles of m CP, TPBi and PBD with sizes from dozens to several hundred nanometers were prepared by solvent antisolvent precipitation method and their solubility were determined by using isothermal saturation method. The saturation solubility of nanoparticles of three kinds of optoelectronic molecules exhibited increase of 12.9%-25.7% in comparison to the same raw materials in the form of microparticles. The experimental evidence indicates that nanonization technology is a feasible way to make optoelectronic molecules dissolve in liquids with enhanced solubility.

基于模糊群决策的绿色供应商选择和订单分配方法

随着市场竞争愈发激烈、全球环境日益恶化以及公众环保意识的提高,绿色采购问题受到了广泛关注。现有研究绝大多数聚焦于考虑绿色准则的供应商选择问题,以实现可持续经营。然而,在综合考虑时间、价格和成本等因素的前提下,从适应性强的供应商处获得适当的产品,对于企业来说更为可行和经济,即供应商选择和订单分配。为了解决上述关键问题,提出了一种模糊环境下的多准则群体决策方法。提出了一种基于理想解相似性偏好排序和层次分析法(technique for order of preference by similarity to ideal solution and analytic hierarchy process,TOPSIS-AHP)的模糊排序方法,该方法可根据企业战略灵活调整传统准则和绿色准则的权重。在双目标优化模型中引入供应商排名进行订货,在实现采购绩效最大化的同时,最大限度地降低采购成本。结果表明:所提方法能够有效评价供应商绩效,并优化候选供应商之间的订单分配。

Solution-processed perovskite solar cells

Perovskite solar cells(PSCs) have emerged as one of the most promising candidates for photovoltaic applications. Low-cost, low-temperature solution processes including coating and printing techniques makes PSCs promising for the greatly potential commercialization due to the scalability and compatibility with large-scale, roll-to-roll manufacturing processes. In this review, we focus on the solution deposition of charge transport layers and perovskite absorption layer in both mesoporous and planar structural PSC devices. Furthermore, the most recent design strategies via solution deposition are presented as well, which have been explored to enlarge the active area, enhance the crystallization and passivate the defects, leading to the performance improvement of PSC devices.

Solution‑Processed Transparent Conducting Electrodes for Flexible Organic Solar Cells with 16.61% Efficiency

Nonfullerene organic solar cells(OSCs)have achieved breakthrough with pushing the efficiency exceeding 17%.While this shed light on OSC commercialization,high-performance flexible OSCs should be pursued through solution manufacturing.Herein,we report a solution-processed flexible OSC based on a transparent conducting PEDOT:PSS anode doped with trifluoromethanesulfonic acid(CF3SO3H).Through a low-concentration and low-temperature CF3SO3H doping,the conducting polymer anodes exhibited a main sheet resistance of 35Ωsq−1(minimum value:32Ωsq−1),a raised work function(≈5.0 eV),a superior wettability,and a high electrical stability.The high work function minimized the energy level mismatch among the anodes,hole-transporting layers and electron-donors of the active layers,thereby leading to an enhanced carrier extraction.The solution-processed flexible OSCs yielded a record-high efficiency of 16.41%(maximum value:16.61%).Besides,the flexible OSCs afforded the 1000 cyclic bending tests at the radius of 1.5 mm and the long-time thermal treatments at 85°C,demonstrating a high flexibility and a good thermal stability.

Current status and trends of carbon-based electrodes for fully solution-processed perovskite solar cells

Perovskite solar cells(PSCs) have revolutionized photovoltaic research. As a result, a certified power conversion efficiency(PCE) of 25.5% was recorded in late 2020. Although this efficiency is comparable with silicon solar cells;some issues remain partially unsolved, such as lead toxicity, instability of perovskite materials under continuous illumination, moisture and oxygen, and degradation of the metallic counter electrodes. As an alternative to tackle this last concern, carbon materials have been recently used, due to their good electrical and thermal conductivity, and chemical stability, which makes them one of the most promising materials to replace metallic counter electrodes in the fabrication of PSCs. This review highlights the recent advances of carbon-based PSCs, where the carbon electrode(CE) is the main actor.CEs have become very promising candidates for PSCs;they are mainly fabricated using a simple combination of graphite and carbon black powders embedded in a binder matrix, giving a paste that is then solution-processable, resulting in devices with improved quality stability, when compared to metallic electrodes. In this review, CE’s composition is emphasized, since it can give both, high and lowtemperature processed electrodes, compatible with different device configurations. Finally, the tendencies and opportunities to use CE in PSCs devices are presented.

Scalable Deposition Methods for Large-Area Production of Perovskite Thin Films

The recent steady improvements in the performance of the nascent hybrid perovskite photovoltaic(PV)devices have led to power conversion efficiencies that rival the best-performing established PV technologies.However,to scale these laboratory demonstrations to PV module-scale production will require development of scalable deposition methods for perovskite thin films.Every record result for perovskite PVs so far was achieved via spin coating,a technique that is popular in research laboratories for thin-film coating over relatively small device areas,but not considered to be a method that could be used to scale up the manufacturing of perovskite PVs.Significantly larger thin-film areas are needed for future commercial PV products.Hence,some researchers have focused their efforts on perovskite deposition techniques that can be considered as scalable for mass production and have achieved notable results even on large areas.Here,we present an overview of the solution-based and vapor-based deposition processes;we explain their influence on the molecular crystal growth behavior of perovskite thin films and discuss the morphology as well as other material quality characteristics.By presenting a comprehensive comparison of the deposition techniques and the corresponding performance parameters for different device sizes,we intent to guide the growing research community through the methods that might enable mass production of perovskite solar products.

Printing photovoltaics by electrospray

Solution processible photovoltaics(PV)are poised to play an important role in scalable manufacturing of low-cost solar cells.Electrospray is uniquely suited for fabricating PVs due to its several desirable characteristics of an ideal manufacturing process such as compatibility with roll-to-roll production processes,tunability and uniformity of droplet size,capability of operating at atmospheric pressure,and negligible material waste and nano structures.This review begins with an introduction of the fundamentals and unique properties of electrospray.We put emphasis on the evaporation time and residence time that jointly affect the deposition outcome.Then we review the efforts of electrospray printing polymer solar cells,perovskite solar cells,and dye sensitized solar cells.Collectively,these results demonstrate the advantages of electrospray for solution processed PV.Electrospray has also exhibited the capability of producing uniform films as well as nanostructured and even multiscale films.So far,the electrospray has been found to improve active layer morphology,and create devices with efficiencies comparable with that of spin-coating.Finally,we discuss challenges and research opportunities that enable electrospray to become a mainstream technique for industrial scale production.

Tetraalkyl-substituted zinc phthalocyanines used as anode buffer layers for organic light-emitting diodes

Two soluble tetraalkyl-substituted zinc phthalocyanines(ZnPcs)for use as anode buffer layer materials in tris(8-hydroxyquinoline)aluminum(Alq3)-based organic light-emitting diodes(OLEDs)are presented in this work.The holeblocking properties of these Zn Pc layers slowed the hole injection process into the Alq3 emissive layer greatly and thus reduced the production of unstable cationic Alq3(Alq3^+)species.This led to the enhanced brightness and efficiency when compared with the corresponding properties of OLEDs based on the popular poly-(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)buffer layer.Furthermore,because of the high thermal and chemical stabilities of these Zn Pcs,a nonaqueous film fabrication process was realized together with improved charge balance in the OLEDs and enhanced OLED lifetimes.

ANALYTICAL SOLUTION OF FILLING AND EXHAUSTING PROCESS IN PNEUMATIC SYSTEM

The filling and exhausting processes in a pneumatic system are involved with many factors, and numerical solutions of many partial differential equations are always adapted in the study of those processes, which have been proved to be troublesome and less intuitive. Analytical solutions based on loss-less tube model and average friction tube model are found respectively by using fluid net theory, and they fit the experimental results well. The research work shows that： Fluid net theory can be used to solve the analytical solution of filling and exhausting processes of pneumatic system, and the result of loss-less tube model is close to that of average friction model, so loss-less tube model is recommended since it is simpler, and the difference between filling time and exhausting time is determined by initial and final pressures, the volume of container and the section area of tube, and has nothing to do with the length of the tube.

Organic bulk heterojunction enabled with nanocapsules of hydrate vanadium pentaoxide layer for high responsivity self-powered photodetector

This article demonstrates the fabrication of organic-based devices using a low-cost solution-processable technique.A blended heterojunction of chlorine substituted 2D-conjugated polymer PBDB-T-2Cl,and PC71BM supported nanocapsules hy-drate vanadium penta oxides(HVO)as hole transport layer(HTL)based photodetector fabricated on an ITO coated glass sub-strate under ambient condition.The device forms an excellent organic junction diode with a good rectification ratio of~200.The device has also shown excellent photodetection properties under photoconductive mode(at reverse bias)and zero bias for green light wavelength.A very high responsivity of~6500 mA/W and high external quantum efficiency(EQE)of 1400%have been reported in the article.The proposed organic photodetector exhibits an excellent response and recovery time of~30 and~40 ms,respectively.

Technology Development and Production of Certain Chemical Platinum Metals Compounds at JSC ＂Krastsvetmet＂

In recent years JSC "Krastsvetmet" has successfully developed the production of chemically pure compounds of precious metals.Currently methods have been developed and facilities have been provided for industrial production of the following platinum metals compounds:Rhodium(Ⅲ) chloride hydrate,rhodium(Ⅲ) chloride solution,rhodium(Ⅲ) nitrate solution,rhodium(Ⅲ) iodide,rhodium(Ⅲ) sulfate,hydrated rhodium(Ⅲ) oxide,ammonium hexachlororodiate,rhodium(Ⅲ) phosphate solution,rhodium electrolytes;Iridium(Ⅳ) chloride hydrate,iridium(Ⅲ) chloride hydrate,ammonium hexachloroiridate(Ⅳ),hexa chloriridium acid solution,hexachloriridium crystalline acid;Ruthenium(Ⅲ) chloride hydrate,ruthenium(Ⅳ) hydroxide chloride,ruthenium(Ⅳ) hydroxide chloride solution,ammonium hexachlororuthenate,ruthenium(Ⅲ) chloride solution,potassium,diaquaoctachloronitrido diruthenate.The quality of the production meets the requirements of Russian and foreign consumers.

Interface passivation engineering for hybrid perovskite solar cells

The allure of high efficiency and low-temperature solution-processed organic-inorganic hybrid perovskite solar cells(PSCs)are inspiring scientists to seek for its commercialization.Interface passivation engineering has become an effective way to further enhance the efficiency and stability of PSCs by defect passivation,reduces the charge recombination and ion migration initiation and hysteresis control,etc.Herein,we have summarized the effects and recent research progress of interface passivation engineering in PSCs.Interface passivation layers can be realized by using the solution and/or vacuum evaporation processes which are very adaptable to varied materials with different properties and fabrication processes for enhanced photovoltaic performance and stability.

Annealing-free alcohol-processable MoO_(X) anode interlayer enables efficient light utilization in organic photovoltaics

Molybdenum oxide(MoO_(x))is a commonly used hole extraction material in organic photovoltaics.The MoO_(x) interlayer is deposited typically via thermal evaporation in vacuum.To meet the need for rollto-roll manufacturing,solution processing of MoO_(x) without post-annealing treatment is essential.Herein,we demonstrate an effective approach to produce annealing-free,alcohol-processable MoO_(x) anode interlayers,namely S-MoO_(x),by utilizing the bis(catecholato)diboron(B_(2) Cat_(2))molecule to modify the surface oxygen sites in MoO_(x).The formation of surface diboron-oxygen complex enables the alcohol solubility of S-MoO_(x).An enhanced light utilization is realized in the S-MoO_(x)-based organic photovoltaics.This affords a superior short-circuit current density(Jsc)close to 26 mA cm^(-2) and ultimately a high power-conversion efficiency(PCE)of 15.2%in the representative PM6:Y6 based inverted OPVs,which is one of the highest values in the inverted OPVs using an as-cast S-MoO_(x) anode interlayer.

Self-Assembled Monolayer of Mixed Gold and Nickel Nanoparticles

Forming a monolayer of mixed nickel and gold nanoparticles through self-assembly via simple solution processing constitutes an important step toward inexpensive nanoparticle-based carbon nanofiber growth.In this work,mixed gold and nickel nanoparticles were anchored on the silicon wafer using self-assembled monolayers(SAMs)as a template.SAMs of 3-mercaptopropyl trimethoxysilane(MPTS-SAMs)were formed on silicon wafer,with the exposed thiol functionality providing ligand exchange sites to form the mixed monolayer of nickel and gold nanoparticles via a two-step sequential soaking approach.The densities of the nickel and gold nanoparticles on the surface can be varied by adjusting the soaking sequence.

Large-area perovskite films for PV applications:A perspective from nucleation and crystallization

Perovskite solar cells(PSCs)have attracted significant research interest due to the rapid rise in efficiency.However,a large efficiency gap still exists between laboratory-based small devices and industrialoriented large-scale modules.One of the main reasons for the efficiency losses is the degraded quality and morphology of the deposited large-area films,which is closely associated with crystallization processes.In this review,we discuss the nucleation and crystallization processes in solution and vaporbased up-scaling deposition methods for large-area perovskite films.We review recent scientific achievements and technical developments that have been made in the field of large-area cells.We present the existing problems that limit the performance of large devices and extensively discuss the key influencing parameters from the perspective of nucleation and crystallization over large areas.This review highlights the importance of crystallization control in up-scaling fabrications and presents promising strategies towards large-area perovskite-based optoelectronic devices.

Solute Redistribution in Directional Melting Process

The solute redistribution in directional melting process is theoretically studied. Based on quantitative evaluations, uniform.solute distribution in liquid and a quasi-steady solute distribution in solid are supposed. The discussion on the solute balance comes to a simple model for the solute redistribution in directional melting process. As an example, the variation of liquid composition during melting process of carbon steel is quantitatively evaluated using the model. Results show that the melting of an alloy starts at solidus temperature, but approaches the liquidus temperature after a very short transient process.

THE SOLUTION OF RANDOM EIGENVALUE PROBLEM WITH SMALL STOCHASTIC PROCESSES

This paper considers an eigenvalue problem containing small stochastic processes. For every fixed is, we can use the Prufer substitution to prove the existence of the random solutions lambda(n) and u(n) in the meaning of large probability. These solutions can be expanded in epsilon regularly, and their correction terms can be obtained by solving some random linear differential equations.

Highly efficient solution-processed organic photovoltaics enabled by improving packing behavior of organic semiconductors

Solution processability is a unique property of organic semiconductors. The compact and regular π-π stacking between molecules is paramount in the performance of organic optoelectronic devices. However, it is still a challenge to improve their stacking quality without sacrificing the solution-processability from the aspect of materials design. Here, delicately engineered additives are presented to promote the formation of ordered aggregation of conjugated molecules by regulating their nucleation and growth dynamics. Intriguingly, the long-chain BTP-eC9-4F molecules can realize ordered aggregation comparable to short-chain ones without sacrificing processability. The domain size of BTP-eC9-4F aggregation is enlarged from 24.2 to 32.2 nm in blend films.Thereby exciton diffusion and charge transport become faster, contributing to the suppression of recombination losses. As a result, a power conversion efficiency of 19.2% is achieved in D18:BTP-eC9-4F based organic photovoltaics. Our findings demonstrate a facile strategy to improve the packing quality of solution-processed organic semiconductors for high-efficiency photovoltaics and beyond photovoltaics.

纤维素纳米片辅助的高导电厚电极的成膜工艺研究

厚电极技术能在不改变电池内部物质/组分/系统配置的情况下,有效提高电池能量密度,因此备受业界关注.然而,缓慢的电荷转移动力学和较差的机械稳定性,阻碍了其实际应用.在此,我们提出了一种由纤维素纳米片辅助的湿法制膜工艺实现了高导电、高负载厚电极的制备.二维结构纤维素纳米片的高表面积、丰富的官能团和优异的机械性能等独特的性质可以促使电极中的导电剂均匀分布,从而在电极内部构建一个三维连续的快速导电网络,同时纤维素片的存在赋予电极良好的力学性能,厚度提升到300μm而不开裂.以此制得的LiCoO_(2)厚电极在50 mg cm-2的高质量负载下循环,可以实现比干电极高6倍的容量保持率.