Tailored multifunctional hydrazine derivatives for efficient printable hole-conductive-free mesoscopic perovskite solar cells via enhancing defect passivation

The low-cost and easy large-scale fabrication advantages of printable mesoscopic perovskite solar cells(p-MPSCs)are overshadowed by their limited photovoltaic conversion efficiency(PCE).Here,we introduce the hydrazide derivative of 4-Hydroxybenzoylhydrazine(4-HBH)to improve the PCE of p-MPSCs by inducing enhanced defect passivation.Both carbonyl and hydrazine groups in hydrazide groups present strong interaction with perovskite.The hydroxyl group,as an electron donor group,increases the electron cloud density of the hydrazide group in 4-HBH under the conjugation of the benzene ring,and thus enhances its interaction with perovskite.Additionally,the hydroxy group itself interacts with perovskite and passivates defects synergistically.The hydrazine agents can also reduce I2and suppress the loss of iodine in perovskite films,which inhibits the formation of iodine-related defects.Consequently,p-MPSCs with 4-HBH achieve a high PCE of 19.21%,and present well improved stability.

Stabilizing perovskite precursors with the reductive natural amino acid for printable mesoscopic perovskite solar cells

Solution processability significantly advances the development of highly-efficient perovskite solar cells.However,the precursor solution tends to undergo irreversible degradation reactions,impairing the device performance and reproducibility.Here,we utilize a reductive natural amino acid,Nacetylcysteine(NALC),to stabilize the precursor solution for printable carbon-based hole-conductorfree mesoscopic perovskite solar cells.We find that I_(2) can be generated in the aged solution containing methylammonium iodide(MI) in an inert atmosphere and speed up the MA-FA^(+)(formamidinium) reaction which produces large-size cations and hinders the formation of perovskite phase.NALC effectively stabilizes the precursor via its sulfhydryl group which reduces I_(2) back to I^(-)and provides H^(+).The NALC-stabilized precursor which is aged for 1440 h leads to devices with a power conversion efficiency equivalent to 98% of that for devices prepared with the fresh precursor.Furthermore,NALC improves the device power conversion efficiency from 16.16% to 18.41% along with enhanced stability under atmospheric conditions by modifying grain boundaries in perovskite films and reducing associated defects.

The opportunities and challenges of ionic liquids in perovskite solar cells

Metal halide perovskite solar cells(PSCs)have shown great potential to become the next generation of photovoltaic devices due to their simple fabrication techniques,low cost,and soaring power conversion efficiency(PCE).However,mismatched with the quickly updated PCEs,the improvement of device stability is challenging and still remains a critical hurdle in the path to commercialization.Recently,ionic liquids(ILs)have been found to play multiple roles in obtaining efficient and stable PSCs.These ILs usually consist of large organic cations and organic or inorganic anions,which have weak electrostatic attraction and are generally liquid at around 100℃.ILs are almost non-volatile,non-flammable,with high ionic conductivity and excellent thermal and electrochemical stability.The roles of ILs in PSCs vary with their composition,that is,the types of anions and cations.In this review,we summarize the roles of anions and cations in terms of precursor solutions,additives,perovskite/charge transport layer interface engineering,and charge transport layers.This article aims to set up a structure–property-stability-performance correlations conferred by the IL in PSC and provide assistance for the anion and cation selection for improving the quality of perovskite film,optimizing interface contact,reducing defect states,and improving charge extraction and transport characteristics.Finally,the application of IL in PSCs is discussed and prospected.

中药植物紫草天然产物的生物合成及其功能研究进展

紫草为我国传统的重要药用植物资源,其根部代谢产生的紫红色萘醌类天然产物—紫草素及其衍生物,临床上常被用于治疗疮疡和皮肤炎症。数十年来,紫草因具高效的多重生物活性、药理作用、良好的临床疗效、较高的利用价值,引起了国内外研究者的重视与关注,正由于此种原因,其野生植物种质资源常遭到大量采挖,生长环境受到严重威胁。随着植物天然产物的生物合成、分子代谢及其生物技术的发展,药用植物天然产物生物活性功能与药理作用研究手段的不断创新,紫草的生物合成途径和相关调控基因的研究取得了显著的进展,紫草素药理作用及其机制得到深入阐明或解析,极大地推进了紫草素的基础性研究及其临床应用开发的进程。本文从紫草分类、紫草素的结构与组成及其生物合成途径、调控紫草素生物合成代谢的功能相关基因以及紫草素生物活性与药理功能等方面综述了相关研究进展,并对未来可能的发展趋势进行了展望,以期为促进我国重要中药材源的药用天然产物的深度挖掘与开发提供有益参考,推动我国传统中药学的现代化发展。

酸铝胁迫土壤中耐铝大豆根际不同部位细菌群落结构、功能及其对促生菌富集作用的研究

针对酸性土壤中影响作物生产的主要限制因子(pH及其铝毒),选用耐酸铝且具有固氮能力的豆科作物是改良该类土壤、促进农业生产的有效措施之一,至于其所关联的根际微生物是否起到相应的促进作用,一直为国内外学者所关注和探究。为此,本研究以铝耐受型大豆品种基因型(BX10)和铝敏感型大豆品种基因型(BD2)为材料,以酸性红壤为生长介质,采样部位按照土层到根系的距离由远到近的顺序划分为:根外对照土(bulk soil,BS)、两侧根际土(rhizospheric soil at two sides,SRH)、刷后根际土(rhizospheric soil after brush,BRH)和冲洗后的根际土(rhizospheric soil after wash,WRH)。利用Illumina MiSeq对16S rRNA基因扩增产物的高变区V4进行高通量测序,研究了不同耐铝基因型大豆根际细菌群落的结构、功能与分子遗传多样性的差异性作用。结果表明,各处理间大豆根际细菌群落的alpha多样性无显著性差异,beta多样性差异也均不显著。PCA和PCoA分析可见BRH和WRH部位的物种组成较为一致,而BS和SRH部位具有相似的物种组成,说明植物生长主要影响根际的BRH及WRH部位的微生物,对SRH影响较小。对各分类水平物种组成和丰度进行比较,门分类水平三元图表明两个基因型大豆均在WRH部位富集蓝细菌门(Cyanobacteria)细菌;统计分析表明铝耐受型大豆(BX10)根部对于增强植物抗逆性的植物根际促生菌(plant growth promoting rhizobacteria,PGPR)有富集作用,这些富集的细菌包括蓝细菌门、拟杆菌门(Bacteroidetes)和变形菌门(Proteobacteria)等,以及部分与固氮和耐铝的功能相关的属种。另对同一个基因型大豆不同采样部位间进行比较分析,结果显示土壤不同采样部位可以选择性富集不同的PGPR物种。此外,16S rDNA的同源蛋白簇(clusters of orthologous groups of proteins,COG)功能预测分析的结果表明,多个COG包括COG0347、COG1348、COG1433、COG2710、COG3870、COG4656、COG5420、COG5456和COG5554均可能与固氮直接相关;BD2相比于BX10,结果显示在BRH和WRH部位似乎均更易富集固氮直接相关的COG,其可能的原因尚待进一步研究。

Effect of variety and seed dressing on emergence of high-oleic peanut under low temperature and high soil humidity conditions

Low temperature coupled with high soil moisture during sowing to emergence generally results in poor peanut stand,thereby posing a non-negligible threat to peanut production in north and northeast China.Five high-oleic(HO)peanut cultivars and 4 seed dressing treatments capable of controlling several diseases and insect pests along with untreated checks were used to find the best combinations to cope with the dual stresses during sowing to emergence period.High broad-sense hereditability estimates of seedling emergence indicated great potential for genetic improvement of this trait.Analysis of variance in the split-plot experiment showed that the main effects of variety and seed dressing and their interaction on seedling emergence were significant.Seed dressing treatments increased seedling emergence percentage by 2.09–35.00 percent points.Four of the 5 HO peanut cultivars yielded satisfactory results.For Huayu 665,Huayu 668 and Huayu 965,Huweisanbao may be the best option;for Huayu 962,Weilidan was highly acceptable.These combinations will be evaluated further in multiple environments before large-scale extension.

Printed hole-conductor-free mesoscopic perovskite solar cells with excellent long-term stability using PEAI as an additive

Phenethylamine（PEA） was successfully introduced into hole-conductor-free, fully printable mesoscopic MAPbI3 perovskite solar cells（MPSCs） with a carbon electrode by mixing phenethylammonium iodide with MAPbI3 perovskite solution. PEA-MAPbI3 films show better pore filling into TiO2 scaffold that forms better contact, and induce longer exciton lifetime and higher quantum efficiency of photoinduced charge separation. As a result, the power conversion efficiency of PEA-MAPbI3 MPSCs is 37% higher than that of MAPbI3 MPSCs. And PEA-MAPbI3 MPSCs show excellent long-term stability that could keep 90% of origin power conversion efficiency for over 80 days in the air.

SiO2 nanoparticle-regulated crystallization of lead halide perovskite and improved efficiency of carbon-electrode-based low-temperature planar perovskite solar cells

SiO2 nanoparticles were used to regulate the crystallizing process of lead halide perovskite films prepared by the sequential deposition method,which was used in the low-temperature-processed,carbon-electrode-basing,hole-conductor-free planar perovskite solar cells.It was observed that,after adding small amount of SiO2 precursor(1 vol%)into the lead iodide solution,performance parameters of open-circuit voltage,short-circuit current and fill factor were all upgraded,which helped to increase the power conversion efficiency(reverse scan)from 11.44(±1.83)%(optimized at 12.42%)to 14.01(±2.14)%(optimized at 15.28%,AM 1.5G,100 mW/cm^2).Transient photocurrent decay curve measurements showed that,after the incorporation of SiO2 nanoparticles,charge extraction was accelerated,while transient photovoltage decay and dark current curve tests both showed that recombination was retarded.The improvement is due to the improved crystallinity of the perovskite film.X-ray diffraction and scanning electron microscopy studies observed that,with incorporation of amorphous SiO2 nanoparticles,smaller crystallites were obtained in lead iodide films,while larger crystallites were achieved in the final perovskite film.This study implies that amorphous SiO2 nanoparticles could regulate the coarsening process of the perovskite film,which provides an effective method in obtaining high quality perovskite film.

Unveiling the effect of amino acids on the crystallization pathways of methylammonium lead iodide perovskites

Multifunctional additives are widely used to improve crystallization and to passivate defects in perovskite solar cells. The roles of these additives are usually related to the various functional groups contained in such additives. Here, we introduce a serious of analogues of amino acids into methylammonium lead iodide perovskites and find they play different roles in the crystallization process despite the fact that these additives share exactly the same terminal groups, namely one amino group and one carboxyl group. The corresponding crystallization pathways are established for the first time via monitoring the time-resolved phase formation and transformation. We find that avoiding the rapid formation of perovskites from precursor solution can facilitate the uniform nucleation and growth of perovskite crystals with enhanced crystallinity and reduced defects. Further, we find the different crystallization behaviors probably arise from the inherent structural characteristic of these additives, leading to different interactions in the precursors. This study unveils the effects of amino acids on the liquid–solid crystallization process and helps better understand the role of multifunctional additives beyond their functional groups.

Combining ability for main quality traits in peanut(Arachis hypogaea L.)

High-oleic peanuts has been recognized by processing sectors,seed sellers and consumers for their longer shelf life,longer seed life and mutiple healthe benefits.High oleate is becoming a requisite for varietal releases in many peanut breeding programs at present.To select desirable parents for high-oleic peanut breeding,the study was conducted to evaluate the combining ability of 5 high-oleic donors from our research team,based on quality of individual single seeds.General combining ability was significant for oleic,linoleic,stearic and palmitic acid,oil and protein,while specific combining ability was significant for the traits except oil.Among them,oil content was found to be conditioned solely by additive gene actions,and for other quality traits,additive gene effects were more important than non-additive gene effects.High-oleic CTW and normal-oleic Xiaojingsheng were selected as the best general combiners for peanut oleic acid improvement.Narrow-sense heritability was high for quality traits other than protein,suggesting that there was high potential for genetic improvement in these traits.

Homogeneous permeation and oriented crystallization in nanostructured mesopores for efficient and stable printable mesoscopic perovskite solar cells

The low-cost and scalable printable mesoporous perovskite solar cells(p-MPSCs) face significant challenges in regulating perovskite crystal growth due to their nanoscale mesoporous scaffold structure, which limits the improvement of device power conversion efficiency(PCE). In particular, the most commonly used solvents, N,N-dimethylformamide(DMF) and dimethyl sulfoxide(DMSO), have a single chemical interaction with the precursor components and high volatility, which is insufficient to self-regulate the perovskite crystallization process, leading to explosive nucleation and limited growth within mesoporous scaffolds. Here, we report a mixed solvent system composed of methylamine formaldehyde(MAFa)-based ionic liquid and acetonitrile(ACN) with the strong C=O–Pb coordination and N–H···I hydrogen bonding with perovskite components. We found that the mixed solvent system is beneficial for the precursor solution to homogeneously penetrate into the mesoporous scaffold,and the strong C=O–Pb coordination and N–H···I hydrogen bonding interaction can promote the oriented growth of perovskite crystals. This synergistic effect increased the PCE of the p-MPSCs from 17.50% to 19.21%, which is one of the highest records for p-MPSC in recent years. Additionally, the devices exhibit positive environmental stability, retaining over 90% of the original PCE after 1,200 h of aging under AM 1.5 illumination conditions at 55 ℃ and 55% humidity.

Achievements,challenges,and future prospects for industrialization of perovskite solar cells

In just over a decade,certifed single-junction perovskite solar cells(PSCs)boast an impressive power conversion efficiency(PCE)of 26.1%.Such outstanding performance makes it highly viable for further development.Here,we have meticulously outlined challenges that arose during the industrialization of PSCs and proposed their corresponding solutions based on extensive research.We discussed the main challenges in this field including technological limitations,multi-scenario applications,sustainable development,etc.Mature photovoltaic solutions provide the perovskite community with invaluable insights for overcoming the challenges of industrialization.In the upcoming stages of PSCs advancement,it has become evident that addressing the challenges concerning long-term stability and sustainability is paramount.In this manner,we can facilitate a more effective integration of PSCs into our daily lives.

A wave propagation model with the Biot and the fractional viscoelastic mechanisms

Energy loss in porous media containing fluids is typically caused by a variety of dynamic mechanisms.In the Biot theory,energy loss only includes the frictional dissipation between the solid phase and the fluid phase,resulting in underestimation of the dispersion and attenuation of the waves in the low frequency range.To develop a dynamic model that can predict the high dispersion and strong attenuation of waves at the seismic band,we introduce viscoelasticity into the Biot model and use fractional derivatives to describe the viscoelastic mechanism,and finally propose a new wave propagation model.Unlike the Biot model,the proposed model includes the intrinsic dissipation of the solid frame.We investigate the effects of the fractional order parameters on the dispersion and attenuation of the P-and S-waves using several numerical experiments.Furthermore,we use several groups of experimental data from different fluid-saturated rocks to testify the validity of the new model.The results demonstrate that the new model provides more accurate predictions of high dispersion and strong attenuation of different waves in the low frequency range.

Enhanced perovskite electronic properties via A-site cation engineering

Organic-inorganic halide perovskites have emerged as excellent candidates for low-cost photovoltaics and optoelectronics.While the predominant recent trend in designing perovskites for efficient and stable solar cells has been to mix different A-site cations,the role of A-site cations is still limited to tune the lattice and bandgap of perovskites.Herein we compare the optoelectronic properties of acetamidinum(Ace)and guanidinium(Gua)mixed methylammonium lead iodide perovskites and shed a light on the hidden role of A-site cation on the carrier mobility of mixed-cation lead iodide perovskites.The cations do not affect the bandgap of the perovskites since the orbitals from Ace and Gua do not contribute to the band edges of the material.However,the mobility of the Ace mixed perovskite is significantly enhanced to be an order of magnitude higher than that of the pristine perovskite.We apply the Ace mixed perovskite in hole-conductor-free printable mesoscopic perovskite solar cells and obtain a stabilized PCE of over 18%(certified 17.7%),which is the highest certified efficiency so far.

不同蔬菜与番茄轮作对设施土壤微生物多样性、酶活性及土壤理化性质的影响

【目的】番茄是一种受连作障碍影响明显的蔬菜作物,本试验旨在研究不同蔬菜作物与番茄轮作后对设施土壤微生物多样性、酶活性及土壤理化性质的影响,以期筛选出适宜与番茄轮作的蔬菜作物,为从设施栽培模式选择角度缓解或避免番茄连作障碍提供理论依据。【方法】试验以连续两茬种植番茄后分别种植大白菜(A)、黄瓜(B)、辣椒(C)、茄子(E)、秋葵(F)、西葫芦(G)6种作物为不同处理,以继续种植番茄(D)和休耕闲置土壤(H)为对照,采用16S rRNA和真菌ITS区测序、同时测定土壤酶活性、pH值、有机质含量、速效氮、磷、钾含量,研究不同蔬菜作物与番茄轮作对土壤微生物多样性、酶活性及土壤理化性质的影响。【结果】种植作物土壤细菌和真菌多样性指数均显著高于闲置土壤(H);番茄连作与轮作土壤中的细菌门水平群落结构比较固定,但不同物种的丰度差异较大。真菌对于环境变化的响应比细菌更加敏感,轮作各样本间真菌群落结构差异明显大于细菌群落结构,在物种丰度和门水平上均存在较大差异;轮作茄子和大白菜显著增加了土壤中硝化细菌[亚硝化单胞菌属(Nitrosomonas)、亚硝化螺菌属(Nitrosospira)]的丰度;PCA分析表明轮作茄子和空白闲置土壤细菌和真菌的群落结构与其他处理的差异较大;轮作不同作物土壤酶活性差异显著,但变化规律不明显。轮作大白菜、黄瓜和空白闲置土壤过氧化氢酶活性显著高于番茄连作和轮作其他作物。不同蔬菜轮作土壤肥力主成分分析结果表明土壤pH值、有机质、速效氮与速效磷是主要贡献因子,综合肥力排名第一的为空白土样,其次为轮作黄瓜的土样,综合肥力最低的为轮作茄子土样。【结论】种植作物可以显著提高土壤微生物多样性;轮作茄子和大白菜显著增加了土壤中硝化细菌的丰度,有利于土壤中氮素代谢和利用;轮作黄瓜和大白菜,显著提高土壤中过氧化氢酶的活性,有利于降低番茄连作产生的自毒作用。因此综合分析认为,茄子、黄瓜和大白菜是避免或缓解番茄连作障碍的潜在优势轮作作物。

Stability improvement under high efficiency—next stage development of perovskite solar cells

With efficiency of perovskite solar cells(PSCs) overpassing 23%, to realize their commercialization, the biggest challenge now is to boost the stability to the same level as conventional solar cells. Thus, tremendous effort has been directed over the past few years toward improving the stability of these cells. Various methods were used to improve the stability of bulk perovskites,including compositional engineering, interface adjustment, dimensional manipulation, crystal engineering, and grain boundary decoration. Diverse device configurations, carrier transporting layers, and counter electrodes are investigated. To compare the stability of PSCs and clarify the degradation mechanism, diverse characterization methods were developed. Overall stability of PSCs has become one central topic for the development of PSCs. In this review, we summarize the state-of-the-art progress on the improvement of device stability and discuss the directions for future research, hoping it provides an overview of the current status of the research on the stability of PSCs and guidelines for future research.

Recent progress in perovskite solar cells:from device to commercialization

Perovskite solar cells(PSCs) are undergoing rapid development and the power conversion efficiency reaches 25.7% which attracts increasing attention on their commercialization recently.In this review,we summarized the recent progress of PSCs based on device structures,perovskite-based tandem cells,large-area modules,stability,applications and industrialization.Last,the challenges and perspectives are discussed,aiming at providing a thrust for the commercialization of PSCs in the near future.

Influence of precursor concentration on printable mesoscopic perovskite solar cells

Over the last decade,the power conversion efficiency of hybrid organic-inorganic perovskite solar cells(PSCs)has increased dramatically from 3.8%to 25.2%.This rapid progress has been possible duc to the accurate control of the morphology and crystallinity of solution-processed perovskites,which are significantly affected by the concentration of the precursor used.This study explores the influence of precursor concentrations on the performance of printable hole-conductor-free meso-scopic PSCs via a simple one-step drop-coating method.The results reveal that lower concentrations lead to larger grains with inferior pore flling,while higher concentra-tions result in smaller grains with improved pore filling.Among concentrations ranging from 0.241.20M,devices based on a moderate strength of 0.70M were confirmed to exhibit the best efficiency at 16.32%.

Highly oriented MAPbI3 crystals for efficient hole-conductor-free printable mesoscopic perovskite solar cells

Highly crystalline perovskite films with large grains and few grain boundaries are conducive for efficient and stable perovskite solar cells.Current methods for preparing perovskite films are mostly based on a fast crystallization process,with rapid nucleation and insufficient growth.In this study,MAPbI3 perovskite with inhibited nucleation and promoted growth in the TiO_(2)/ZrO_(2)/carbon triple mesoscopic scaffold was crystallized by modulating the precursor and the crystallization process.N-methylformamide showed high solubility for both methylammonium iodide and Pbl2 and hampered the formation of large colloids in the MAPbI3 precursor solution.Furthermore,methylammonium chloride was added to reduce large colloids,which are a possible source of nucleation sites.During the crystallization of MAPbI3,the solvent was removed at a slow controlled speed,to avoid rapid nucleation and provide sufficient time for crystal growth.As a result,highly oriented MAPbI3 crystals with suppressed non-radiative recombination and promoted charge transport were obtained in the triple mesoscopic layer with disordered pores.The corresponding hole-conductor-free,printable mesoscopic perovskite solar cells exhibited a highest power conversion efficiency of 18.82%.The device also exhibited promising long-term operational sta-bility of 1000 h under continuous illumination at maximum power point at 55±5°C and damp-heat stability of 1340 h aging at 85°C as well as 85%relative humidity.

Oxygen makes better inorganic perovskite solar cells

Halide perovskites have attracted enormous attention and made great progress recently,especially in photovoltaic field.Compared with the widely used hybrid organic-inorganic halide perovskites(HHPs),all-inorganic halide perovskites(IHPs)have the following unique advantages:(i)high thermal stability due to the replacement of volatile organic cations with inorganic cations such as Cs+;(ii)high chemical stability with no concerns about the deprotonation of the organic components under the effect of oxygen and light illumination[1,2].