Unraveling abnormal buried interface anion defect passivation mechanisms depending on cation-induced steric hindrance for efficient and stable perovskite solar cells

Although ionic liquids(ILs)have been widely employed to heal the defects in perovskite solar cells(PSCs),the corresponding defect passivation mechanisms are not thoroughly understood up to now.Herein,we first reveal an abnormal buried interface anion defect passivation mechanism depending on cationinduced steric hindrance.The IL molecules containing the same anion([BF4]^(-))and different sizes of imidazolium cations induced by substituent size are used to manipulate buried interface.It was revealed what passivated interfacial defects is mainly anions instead of cations.Theoretical and experimental results demonstrate that the large-sized cations can weaken the ionic bond strength between anions and cations,and facilitate the interaction between anions and SnO2as well as perovskites,which is conducive to interfacial defect passivation and ameliorating interfacial contact.It can be concluded that interfacial chemical interaction strength and defect passivation effect are positively correlated with the size of cations.The discovery breaks conventional thinking that large-sized modification molecules would weaken their chemical interaction with perovskite.Compared with the control device(21.54%),the device based on 1,3-Bis(1-adamantyl)-imidazolium tetrafluoroborate(BAIMBF4)with maximum size cations achieves a significantly enhanced efficiency of 23.61%along with much increased moisture,thermal and light stabilities.

Relative contributions of temperature and salinity to steric sea level over the South China Sea

The relative contributions of surface temperature and salinity to steric sea-level variations are investigated using satellite observations and reanalysis datasets.By defi ning a contribution factor,the relative roles of thermal and haline steric height variations are quantifi ed over the South China Sea(SCS).The thermosteric height dominates the steric sea level variation in the northern SCS deep basin,while the contribution of the halosteric height increases southward.Further investigation reveals that this transition is related to the meridional imbalance of surface heat flux and precipitation variations.The revealed steric constitution distribution is not confi ned to the surface but extends within the upper layer to approximately 50m depth,and then the thermosteric component dominates from the depth underneath.The results of this study clarify the steric sea level constitution over the SCS,benefit the understanding of sea-level variations at the regional scale,and may further facilitate multisensor remote sensing data mining studies.

THE STEPWISE EXCHANGE ACTION AND STERIC HINDRANCE EFFECT OF ORGANIC PHENOLS ON CLAYS IN SEAWATER

The exchange action of six types of organic phenols on clay surfaces in seawater is systematically studied in this work. The following significant conclusions are drawn from the experiments. (1) The interaction of organic phenols with montmorillonite, illite and kaolinite in seawater is monovalent anion exchage.(2) Their isotherms of stepwise exchage on clay surfaces belong to the Langmuir type or stepwise type.(3) The discovery of the"steric hindrance effects of stepwise exchange of organic phenols on clays surfaces", and revelation of an exchange mechanisrn diffeient from that in references are the greatest achieverments in this work.

Comparing the steric height in the Nordic Seas with satellite altimeter sea surface height

In this study the steric height anomaly which is calculated from the hydrological data （EN3） is compared with the sea level anomaly derived from satellite altimetry in the Nordic Seas. The overall pattern of steric height is that it is higher in the margin area and lower in the middle area. The extreme values of steric height linear change from 1993 to 2010 occur in the Lofoten Basin and off the Norwegian coast, respectively. Such a distribution may be partly attributed to the freshening trend of the Nordic Seas. The correlation between SLA （sea level anomaly） and SHA （steric height anomaly） is not uniform over the Nordic Seas. The time series of SLA and SHA agree well in the Lofoten Basin and northern Norwegian Basin, and worse in the northern Norwegian Sea, implying that the baroclinic effect plays a dominant role in most areas in the Norwegian Sea and the barotropic effect plays a dominant role in the northern Norwegian Sea. The weaker correlations between SLA and SHA in the Greenland and Iceland Seas lead a conclusion that the barotropic contribution is significant in these areas. The area-mean SHA over the entire Nordic Seas has similar amplitudes compared with the SLA during 1996-2002, but SHA has become lower than SLA, being less than half of SLA since 2006.

Steric Sea Level Change in Twentieth Century Historical Climate Simulation and IPCC-RCP8.5 Scenario Projection: A Comparison of Two Versions of FGOALS Model

To reveal the steric sea level change in 20th century historical climate simulations and future climate change projections under the IPCC＇s Representative Concentration Pathway 8.5 （RCP8.5） scenario, the results of two versions of LASG/IAP＇s Flexible Global Ocean-Atmosphere-Land System model （FGOALS） are analyzed. Both models reasonably reproduce the mean dynamic sea level features, with a spatial pattern correlation coefficient of 0.97 with the observation. Characteristics of steric sea level changes in the 20th century historical climate simulations and RCPS.5 scenario projections are investigated. The results show that, in the 20th century, negative trends covered most parts of the global ocean. Under the RCPS.5 scenario, global-averaged steric sea level exhibits a pronounced rising trend throughout the 21st century and the general rising trend appears in most parts of the global ocean. The magnitude of the changes in the 21st century is much larger than that in the 20th century. By the year 2100, the global-averaged steric sea level anomaly is 18 cm and 10 cm relative to the year 1850 in the second spectral version of FGOALS （FGOALS-s2） and the second grid-point version of FGOALS （FGOALS-g2）, respectively. The separate contribution of the thermosteric and halosteric components from various ocean layers is further evaluated. In the 20th century, the steric sea level changes in FGOALS-s2 （FGOALS-g2） are largely attributed to the thermosteric （halosteric） component relative to the pre-industrial control run. In contrast, in the 21st century, the thermosteric component, mainly from the upper 1000 m, dominates the steric sea level change in both models under the RCPS.5 scenario. In addition, the steric sea level change in the marginal sea of China is attributed to the thermosteric component.

SYNTHESIS OF NOVEL BI-FUNCTIONAL COPOLYMER BEARING STERICALLY HINDERED PHENOL AND HINDERED AMINE GROUPS VIA RING-OPENING METATHESIS POLYMERIZATION

Norbornene derivatives exo,endo-2-[2-(3,5-di-tert-butyl-4-hydroxyphenoxy)-acetoxy]methyl-5-norbornene(M1) and 3,3,5,5-tetramethyl-4-piperidinyl 5-norbornene-exo,endo-2-carboxylate(M2)were synthesized and polymerized by RuCl_2(=CHPh)(PCy_3)_2 to prepare a novel kind of bi-functional polymer bearing sterically hindered phenol(SHP)and hindered amine(HLAS)groups via ring-opening metathesis polymerization(ROMP).The resulting copolymers were characterized by gel permeation chromatography(GPC),~1H-NMR and differen...

Influence of Steric Hindrance Between Hydrogen Atoms of Linkage Groups and Adjacent Phenyls on Properties of Polyimide

A diamine monomer 4,4′-methylenedianiline（MDA） was introduced to modify the polyimide of pyromellitic dianhydride（PMDA） and 4,4′-oxydianiline（ODA） by polycondensation. A series of polyamic acids was synthesized from MDA and ODA of different molar ratios with PMDA of sum mole of moles of MDA and ODA, and polyimide films were obtained by thermal imidization. Polyimide（PI） films were characterized by tensile testing, dynamic mechanical analysis（DMA）, thermal gravimetry analysis（TGA）, Fourier transform infrared spectroscopy （FTIR）, wide X-ray diffraction（WAXD） and molecular simulation. With the increase of MDA content, the tensile strength and thermal decomposition temperature remained generally stable compared with those of PMDA/ODA polyimide. Unexpectedly, the glass transition temperature（Tg） and Young＇s modulus increased from 388.7 °C and 2.37 GPa to 408.3 °C and 5.74 GPa, respectively. The results of WAXD and molecular simulation indicate the steric hindrance among hydrogen atoms of the linkage groups and adjacent phenyls enhanced the properties of the polyimide modified with MDA.

CALCULATION OF MOLECULAR INTERNAL ROTATING STERIC FACTOR OF FLUOROPOLYMERS BY RADIATION CROSSLINKING METHOD

In this paper, the relationship between radiation crosslinking parameter β and the molecular internal rotating steric factor (σ) for fluoropolymers were studied. An expression calculating the molecular internal rotating steric factor of fluoropolymers, σ=1.44+(β-0.206)/1.946, was established. σ value obtained by this method is in agreement with that given in the literature.

Competition between Band Filling and Steric Effect in Ordered Double Perovskites Sr_(2-x)La_xMnMoO_6

The ordered double perovskites, Sr2-xLaxMnMoO6, were prepared by sol-gel reaction. Structural, magnetic, and electrical properties were investigated for a series of ordered double perovskites Sr2- x Lax MnMoO6 （0 ≤ x ≤ 1 ）. The compounds have a monoclinic structure （space group P21/n） and the cell volume expands monotonically with La doping. The Tc and the magnetic moment rise and the cusp-like transition temperature below which the magnetic frustration occurs shifts to high temperature as x increases. With La doping, electrical resistivity of Sr2-x LaxMnMoO6 decreases only at low doping levels （x ≤0.2）; while at high doping levels （0.8≤x ≤1）, electrical resistivity tends to increase greatly. The resuits suggest that the competition between band filling effect and steric effect coexists in the whole doping range, and the formation of ferrimagnetic interactions is not simply at the expense of antiferromagnetic interactions.

Steric Effect Modulating the Structures of Trinuclear Zinc Carboxylate Frameworks

By the reaction of different aromatic dicarboxylic acid with zinc nitrate, three metal-carboxylate frameworks, [Zn3（BDC）3（EtOH）2]（1）, [Zn3（BDC）3（py）2]·2DMF（2）, and [Zn3（NH2-BDC）3（H2O）2]·5DMF（3） which are constructed on the same linear trinuclear Zn3（RCOO）6 secondary building units, have been synthesized and characterized by X-ray diffraction analyses. Structural analyses showed that there are terephthalic acids as ligand linkers to form the hxl topological layer structures for 1 and 2. The introduction of the rigid aromatic ring pyridine in 2 as the terminal co-ligand of Zn3-SBU to instead of the flexible ethanol in 1, will form the layer-pillared supramolecular systems with 2-D crisscross channels, through its π-π stacking interactions. Owing to the steric hindrance of amino groups, 3 was assembled into a three-dimensional porous structure with pcu topology derived from the 2-amino-terephthalic acid as linkers to connect the Zn3-SBUs through a head-to-tail type.

Synthesis of substituted polyaryls via sterically hindered double Suzuki cross-couplings

代替的 polyaryls 经由妨碍的位的联盟者成功地被综合面对 Pd 与芳基 dibromides 加倍 arylboronic 酸的铃木 cross-couplings (PPh 3)4 和击倒 t 在一很短的时间以内的 Bu。

An Analysis of the Steric Sea Level Change by Introducing Sea Surface Temperature

In this paper, we use the optimum interpolation sea surface temperature (OISST) provided by the National Center for Environmental Prediction (NCEP) to replace the temperature in the top three layers in the ISHII data, and make use of the modified ISHII temperature data to calculate the thermosteric sea level (called modified steric sea level (SSL) hereafter). We subtract the modified SSL and the steric sea level (called ordinary SSL hereafter) derived from the ISHII temperature and salinity from the steric sea level (SSL) provided by the Gravity Recovery and Climate Experiment (GRACE), respectively, and find that the rms error of the difference of the former is obviously smaller than that of the latter. Therefore we reach the conclusion that under the assumption that the GRACE SSL is accurate, the modified SSL can reflect the true steric sea level more accurately. Making use of the modified SSL, we can find that the modified SSL in sea areas of different spatial scales shows an obvious rising trend in the upper 0-700 m layer for the period 1982-2006. The global mean SSL rises with a rate of 0.6 mm year-1 .The modified SSLs in sea areas of different spatial scales all show obvious oscillations with period of one year. There are oscillations with periods of 4-8 years in global oceans and with periods of 2-7 years in the Pacific. The Empirical Orthogonal Function method is applied to the sea areas of different spatial scales and we find that the first modes all have obvious 1-year period oscillations, the first mode of the global ocean has 4-8 year period oscillations, and that of the Pacific has 2-6 year period oscillations. The spatial distribution of the linear rising trend of the global modified SSL in the upper 0-700 m layer is inhomogeneous with intense regional characteristics. The modified SSL linear trend indicates a zonal dipole in the tropical Pacific, rising in the west and descending in the east. In the North Atlantic, the modified SSL indicates a meridional dipole, rising in the latitude band of 20°N-40°N and 45°N-65.5°N and descending obviously in the latitude band of 40°N-45°N.

Seasonal Change of Steric Sea Level in the GIN Seas

The Greenland Sea,Iceland Sea,and Norwegian Sea (GIN seas) form the main channel connecting the Arctic Ocean with other Oceans,where significant water and energy exchange take place,and play an important role in global climate change.In this study steric sea level,associated with temperature and salinity,in the GIN seas is examined based on analysis of the monthly temperature and salinity fields from Polar science center Hydrographic Climatology (PHC3.0).A method proposed by Tabata et al.is used to calculate steric sea level,in which,steric sea level change due to thermal expansion and haline contraction is termed as the thermosteric component (TC) and the halosteric component (SC),recpectively.Total steric sea level (TSSL) change is the sum of TC and SC.The study shows that SC is making more contributions than TC to the seasonal change of TSSL in the Greenland Sea,whereas TC contributes more in the Norwegian and the Iceland Seas.Annual variation of TSSL is larger than 50 mm over most regions of the GIN Seas,and can be larger than 200 mm at some locations such as 308 mm at 76.5 N,12.5 E and 246 mm at 77.5 N,17.5 W.

Suitability of Steric Mass-action Model for Ion-exchange Equilibrium of Micromolecule

The steric mass-action (SMA) model has been widely reported in the literature for ion-exchange and metal-affinity interaction adsorption equilibrium of biomacromolecules. In this paper, the usefulness of SMA model is analyzed for describing micromolecule ion-exchange equilibrium onto cation exchangers, CM Sephadex C-25 and Streamline SP. Batch adsorption experiments with ephedrine hydrochloride as a model adsorbate are carried out to determine the model parameters, that is, steric factor, characteristic charge and equilibrium constant. The result shows that the SMA model parameters of micromolecule cannot be obtained using the nonlinear least-square fitting method as protein's due to the remarkable difference between the molecular mass and dimension of micromolecule and protein. It is considered that the small size of the adsorbates dealt with in this study justifies the neglect of steric hindrances arising from adsorbate bulkiness. Thus, the three-parameter SMA model is reduced to two-parameter one (i.e., steric factor is equal to zero) for describing micromolecule ion-exchange equilibrium. It is found that the equilibrium constant for CM Sephadex C-25 increases with increasing ionic strength, while the equilibrium constant for Streamline SP shows an opposite trend. This is probably due to the remarkable difference between the physicalpro perties of the two adsorbents. Then, the relationship between the equilibrium constant and ionic strength is described by an expression. The computer simulations show that, the theoretical model with the correlation is promising in the prediction of micromolecule adsorption decrease with increasing ionic strength in a wide range of salt concentration.

Steric Effects in the Cl＋CHD3（v1=1） Reaction

最近的研究揭示了完整的 3dimentional 反应 C1+CHD3 (v1=1 ) 的反应散布图画当 Cl 原子从对拉长的 CH 各自的各种各样的方向攻击 CHD3，结合。报导 polarizationdependent 微分生气的节提供对反应的试剂排列的影响的最详细的描述。传送对一般化学家更可存取的 stereospecific 信息，我们这里出现由合适的对称考虑，怎么从大小检索相对积分和二很普通的碰撞几何学的微分生气的节：在端点对 sideon 攻击。结果，虽然 coarsegrained，提供不仅关于化学反应增强我们的直觉，而且打开更多的灯在上的一幅呼吁的图画常规(unpolarized ) 属性。

Steric Effect of Alkyl Substituted Piperidin-4-one Oximes for Corrosion Control of Mild Steel in H_2SO_4 Medium

Three synthesized piperidin-4-one oximes,3-ethyl-2,6-diphenyl-piperidin-4-one oxime(A),1-methyl-3-isopropyl-2,6-diphenyl-piperidin-4-one oxime(B),and 3-isopropyl-2,6-diphenyl-piperidin-4-one oxime(C),were tested at different concentrations to determine their ability to inhibit corrosion of mild steel in 1 mol.L-1 H2SO4 and measured by a mass loss method(at various temperatures),polarization and impedance measurements,X-ray diffraction(XRD),scanning electron microscopy(SEM) with energy-dispersive X-ray spectroscopy(EDS),and a quantum chemical method.The synergistic influence of compounds A,B and C with iodides has also been evaluated.All three compounds show good inhibition efficiency in the following order:A>B>C.Compounds A,B and C were found to physically adsorb on the surface of mild steel while obeying the Temkin isotherm.Polarization measurements indicated that these compounds behave as a mixed mode inhibitor.XRD and SEM with EDS studies revealed the formation of a protective barrier on the mild steel surface by these oximes.The electron donating ability of the studied molecules was tested using semi empirical methods.The studies revealed that the oxime nitrogen,the piperidine moiety,and the phenyl ring assist largely in corrosion control.The studies also showed that the steric crowding by the alkyl group in the piperidine ring affects the inhibitor efficiency.Further,it is interesting to note that all of the studied compounds exhibit synergism with iodide ions.

Which Information Theoretic Quantity Should We Choose for Steric Analysis of Water Nanoclusters(H2O)n(n=6,32,64)?

As evidenced from recent literature,interest in employing information theory measures for understanding different properties of atomic and molecular systems is increasing tremendously.Following our earlier efforts in this field,we here evaluate the feasibility of using information theory functionals such as Fisher information,Shannon entropy,Onicescu information energy,and Ghosh-Berkowitz-Parr entropy as measures of steric effects for the steric analysis of water nanoclusters.Taking the structural isomers of water hexamers as working models and using information theoretic quantities,we show that the relative energies of water nanoclusters and the computed steric energies are related.We also show the strong effects of steric repulsion on conformational stabilities.At the same time,we have also assessed the usefulness of simultaneously considering the different information theoretic quantities,and achieved more accurate descriptions of the stability of water nanoclusters.In order to consider the effects of cluster size on the obtained results and the extent of applicability of information theoretic quantities,we have also benchmarked larger water nanoclusters with 32 and 64 units.Scrutinizing the obtained data from information theory functionals,we found that Fisher information shows the best overall performance.Our findings underline that the information theoretic quantities,especially Fisher information,can be used as quantitative measures of relative energies and consequently the order of stability of nanoclusters,which affirmed the utility of information theory for investigating various physical and chemical problems.

Branch-Chain-Rich Diisopropyl Ether with Steric Hindrance Facilitates Stable Cycling of Lithium Batteries at-20°C

Li metal batteries(LMBs)offer signifi-cant potential as high energy density alternatives;nev-ertheless,their performance is hindered by the slow desolvation process of electrolytes,particularly at low temperatures(LT),leading to low coulombic efficiency and limited cycle stability.Thus,it is essential to opti-mize the solvation structure thereby achieving a rapid desolvation process in LMBs at LT.Herein,we introduce branch chain-rich diisopropyl ether(DIPE)into a 2.5 M Li bis(fluorosulfonyl)imide dipropyl ether(DPE)elec-trolyte as a co-solvent for high-performance LMBs at-20°C.The incorporation of DIPE not only enhances the disorder within the electrolyte,but also induces a steric hindrance effect form DIPE’s branch chain,excluding other solvent molecules from Li+solvation sheath.Both of these factors contribute to the weak interactions between Li^(+)and solvent molecules,effectively reducing the desolvation energy of the electrolyte.Consequently,Li(50μm)||LFP(mass loading~10 mg cm^(-2))cells in DPE/DIPE based electrolyte demonstrate stable performance over 650 cycles at-20°C,delivering 87.2 mAh g^(-1),and over 255 cycles at 25°C with 124.8 mAh g^(-1).DIPE broadens the electrolyte design from molecular structure considera-tions,offering a promising avenue for highly stable LMBs at LT.

The Influence of Various Cationic Group on Polynorbornene Based Anion Exchange Membranes with Hydrophobic Large Steric Hindrance Arylene Substituent

A series of brominated polynorbornene derivatives,including bulky steric hydrophobic groups and highly physical and chemical stable backbones,were synthesized via ring-opening metathesis polymerization and post-functionalized with trimethylammonium(QA),N-methylimidazole(Im),N-methylpyrrolidinium(Pyr)or N-methylpiperidinium(Pip)to construct the entire anion exchange membranes(AEMs).Benefited from prominent phase-separated morphology,PBO-x%-y(x=66,68,70;y=QA,Im,Pyr,Pip)AEMs with ion exchange capacity(IEC)approaching 2.0 meq·g^(−1)exhibited super high hydroxide conductivities.Thereinto,PBO-70%-Pip possessed the highest hydroxide conductivity of 137.3 mS·cm^(−1)at 80℃Moreover,all membranes exhibit low swelling ratio(SR)(the SR of PBO-66%-QA was just 8.6%at 80℃).That is,bulky steric hydrophobic groups play a crucial role in balancing the high hydroxide conductivity and low SR in AEMs.Furthermore,three AEMs(PBO-66%-QA,PBO-68%-Pyr,PBO-70%-Pip)showed good alkaline stability after immersion into 1.0 mol/L NaOH aqueous solution at 80℃for 480 h without any degradation.

Steric hindrance effect of Schiff-base ligands on magnetic relaxation dynamics and emissive behavior of two dinuclear dysprosium complexes

The self-assembly reactions between mixed-ligand and tetrahydrate dysprosium acetate in the presence of mixed organic solvents lead to two structural similar dinuclear dysprosium complexes with composition formulas of Dy_(2)(L_1)_(2)(L_(2))_(2)(CH_(3)OH)_(2)·CH_(2)Cl_(2)·CH_(3)OH(1) and Dy_(2)(L_1)_(2)(L_(3))_(2)(CH_(3)OH)_(2)·CH_(3)CN(2),where L_1,L_(2) and L_(3) represent the deprotonated form of 4-tert-butyl-2-(7-methoxybenzo[d]oxazol-2-yl)phenol,(E)-1-(((3,5-di-tert-butyI-2-hydroxyphenyI)imino)methyl)naphthalen-2-ol and(E)-2,4-di-tertbutyl-6-((2-hydroxybenzylidene)amino)phenol.The tiny difference of the core structure of 1 and 2 is derived from the steric hindrance of Schiff base ligands L_(2) and L_(3).Dynamic magnetic measurements reveal that 1 and 2 show frequency-dependent out-of-phase alternating-current susceptibility signal peaks at different temperatures under zero dc field,diagnostic of single-molecule magnet behavior.The experimental derived energy barrier to magnetization reversal for 1 and 2 is 108(1),47(2) and 33(3) K.Ab initio CASSCF calculations performed on 1 and 2 suggest that the origin of the difference in magnetic properties originates from the variation in the single-ion anisotropy that arises due to minor structural variation.Further,the equation to calculate the effective energy barrier for Dy_(2) proposed earlier is found to yield an excellent agreement with the experimental results.Solid state fluorescence measurements performed on 1 and 2 demonstrate that both exhibit two ligands centered components of fluorescent emissive,in addition,with different emitting colors and chromaticity coordinates.The discrepancy of fluorescence and single molecule magnet behavior showed by 1 and 2 can be attributed to the steric hindrance effect of Schiff base ligands.