Stability of mixed-halide wide bandgap perovskite solar cells: Strategies and progress

Benefiting from the superior optoelectronic properties and low-cost manufacturing techniques,mixedhalide wide bandgap(WBG)perovskite solar cells(PSCs)are currently considered as ideal top cells for fabricating multi-junction or tandem solar cells,which are designed to beyond the Shockley-Queisser(S-Q)limit of single-junction solar cells.However,the poor long-term operational stability of WBG PSCs limits their further employment and hinders the marketization of multi-junction or tandem solar cells.In this review,recent progresses on improving environmental stability of mixed-halide WBG PSCs through different strategies,including compositional engineering,additive engineering,interface engineering,and other strategies,are summarized.Then,the outlook and potential direction are discussed and explored to promote the further development of WBG PSCs and their applications in multijunction or tandem solar cells.

Residual solvent extraction via chemical displacement for efficient and stable perovskite solar cells

Solvent residue is inevitable to occur in solution processed thin films,but its influence on the thin film quality has not been identified and addressed to date.Methylammonium acetate(MAAc)ionic liquid has recently been realized as an environmentally friendly solvent for solution processed perovskites.The specific high viscosity,low vapor pressure and strong association with perovskite precursor of the MAAc solvent is a double-edged sword,which endowed an advantageously ambient air operational and anti-solvent free perovskite deposition,but the MAAc is likely to be retained within the film and bring in detrimental effects on device performance of the corresponding solar cells.Herein,we reported a novel route to eliminate the residual solvent via a facial hydrochloric acid(HCl)annealing post-treatment(HAAP).In particular,chemical displacement reaction between the incorporated HCl and residual MAAc can be initiated to form volatile MACl and HAc,efficiently extracting MAAc residue.In the meanwhile,the stimulated mass transport via downward penetration and upward escape can trigger secondary perovskite growth with enlarged grain size and smoothened surface,leading to reduced defect state and improved interfacial contact intimacy,and also partial chloride ions are able to enter the crystal lattice to stabilize perovskite phase structure.As a result,a champion efficiency up to20.78%originating from enhanced Voc was achieved,and more than 96%of its initial efficiency can be maintained after 1000 h shelf-storage.

Effective-Spring Model of Tympanic Response in Archosaurs

Whereas for smaller animals the eardrums are well-characterized as excitable membranes or drums, some animals such as several archosaurs feature, as a first approximation, a rather stiff elastic shell supported by an elastic ring. Mathematically, the theory of plates and shells is applicable but its governing equations overly complicate the modeling. Here the notion of tympanic structure is introduced as a generalization of “ordinary” tympanic membranes so as to account for sound perception as it occurs in archosaurs, such as birds and crocodilians. A mathematical model for the tympanic structure in many archosaurs called two-spring model implements this notion. The model is exactly soluble and solutions are presented in closed form and as a series expansion. Special emphasis is put onto offering an easy-to-apply model for describing experiments and performing numerical studies. The analytic treatment is supplemented by a discussion of the applicability of the two-spring model in auditory research. An elasticity-theoretic perspective of the two-spring model is given in the Appendix.

Chiral cation promoted interfacial charge extraction for efficient tin-based perovskite solar cells

Pb-free Sn-based perovskite solar cells(PSCs) have recently made inspiring progress, and power conversion efficiency(PCE) of 14.8% has been achieved. However, due to the energy-level mismatch and poor interfacial contact between commonly used hole transport layer(i.e., poly(3,4-ethylenedioxythio phene):poly(styrene sulfonate), PEDOT:PSS) and FASnI_(3) film, it is still challenging to effectively extract holes at the interface. Owing to the p-type nature of Sn-based perovskites, the efficient hole extraction is of particular significance to improve the PCE of their solar cells. In this work, for the first time, the role of chiral cations, a-methylbenzylamine(S-/R-/rac-MBA), in promoting hole transportation of FASnI_(3)-based PSCs is demonstrated. The introduction of MBAs is found to form 2D/3D film with lowdimensional structures locating at PEDOT:PSS/FASnI_(3) interface, which facilitates the energy level alignment and efficient charge transfer at the interface. Importantly, chiral-induced spin selectivity(CISS)effect of R-MBA_(2)SnI_(4)induced by chiral R-MBA cation is found to further assist the specific interfacial transport of accumulated holes. As a result, R-MBA-based PSCs achieve decent PCE of 10.73% with much suppressed hysteresis and enhanced device stability. This work opens up a new strategy to efficiently promote the interfacial extraction of accumulated charges in working PSCs.

Impact of Vector-Current Interactions on the QCD Phase Diagram

Using a nonlocal version of the Polyakov-loop-extended Nambu-Jona-Lasinio model, we investigate effects of a nonderivative vector-current interaction (relating to the quark-number density) at both real and imaginary chemical potentials. This repulsive vector interaction between quarks has the following impact on the chiral first-order phase transition: at imaginary chemical potential it sharpens the transition at the Roberge-Weiss (RW) end point and moves this critical point toward lower temperatures;at real chemical potential, the critical end point moves on a trajectory towards larger chemical potentials and lower temperatures with increasing vector coupling strength. The conditions are discussed at which the first-order phase transition disappears and turns into a smooth crossover.

能量密度泛函理论和有限力程可分离对相互作用研究核的超流性质

在相对论密度泛函理论框架下引入了可分离的对相互作用,它的参数是由拟合核物质中Gogny力对关联性质来确定。在有限核的相对论Hartree-Bogoliubov和相对论准粒子无规位相近似的理论框架下,建立了可分离对相互作用在球形核和变形核中粒子-粒子道矩阵的计算方法。通过Talmi和Moshinsky变换,这种新的对相互作用在坐标空间下可以展开成一系列可分离项,并且很快收敛。它不仅保持了平移不变性,而且作为有限力程的对力,可以避免零程对力在高动量截断的困难。通过对Sn同位素链核基态、E2和E3激发态性质,以及Sm同位素链基态的性质研究,发现可分离对相互作用能够再现用Gogny对力得到的球形核的超流性质,并能够很好地符合已有的实验结果。这种方法还可用来描述任意微观对相互作用,并推广于三轴形变原子核以及转动系统的研究。为考虑角动量投影和粒子数投影的生成坐标(GCM)方法和粒子-振动耦合(PVC)理论提供更加真实的对关联性质描述。

亚表面引发原子转移自由基聚合构筑温度响应型纳米纤维油水分离膜

亚表面引发聚合是一种用于制备共价嵌入型聚合物刷的新型改性策略.该方法在发展高稳定性聚合物刷功能化表界面材料方面具有显著的优势.本工作利用亚表面引发原子转移自由基聚合(sSI-ATRP)对静电纺丝聚丙烯腈(PAN)基纳米纤维膜进行亚表面改性,通过接枝聚N-异丙基丙烯酰胺(PNIPAM)制备了温度响应型纳米纤维油水分离膜(PAN-sg-PNIPAM).当温度低于低临界溶解温度(LCST)时,PNIPAM链与水分子之间的强氢键作用使得聚合物链完全伸展,分离膜表面亲水且对油滴具有非常低的粘附力,对油水乳液具有非常高的分离效率(达98.7%);当温度高于LCST时,PNIPAM链失水收缩,膜表面变得更加疏水且对油滴的粘附力显著增加,其油水乳液分离效率显著降低,仅为9.1%.此外,由于共价嵌入聚合物刷的高稳定性,该分离膜在4 kPa压力下,20℃和45℃之间可逆切换10个循环后,仍能保持非常稳定的渗透通量.本研究为发展高稳定性的智能型油水分离膜提供了一种新方法.

Interaction between integrin α_(Ⅱb)β3 and synthesized cyclic hexapeptide containing RGD

The RGD sequence generally exists in the extracellular matrix proteins and can be recognized by many integrin proteins. The binding ability of immobilized biotinylated cyclic hexapeptide [cyclo(-Arg-Gly-Asp-D-Phe-Lys-Gly-)] containing RGD to integrin ααbβ3 was tested by the methods of ELISA and SPR. Results showed that a spacer of 1.48-2.2 nm between the peptide and the biotin residue was long enough to send the RGD sequence into the binding center embedded within αⅡbβ3, and the equilibrium dissociation constant was 1.1μm. The work provides an ideal model system for the research of cell adhesion on solid surfaces.

Complete thermoelectric benchmarking of individual InSb nanowires using combined micro-Raman and electric transport analysis

Nanowires (NW ) 是为在热电的行为上探索低维数和热传导性抑制的效果的理想的 nanostructures。然而，它正在质问精确地在如此的系统测量温度坡度和热流动。用空间地解决的拉曼光谱学和运输大小的联合，这里，我们决定单个做 Se 的 InSb NW 的所有热电的性质并且确定优点 ZT 的数字。在 NW 和联系电的反应的测量导致激光的加热被一个 1D 热方程模型很好描述。我们的方法在来源和 NW 的排水管电极允许热接触电阻的决心，它在我们的系统是可以忽略的。InSb NW 的测量热电的参数同意很好，那些基于地效果晶体管 Seebeck 大小获得了。

Efficient and stable Ruddlesden-Popper layered tin-based perovskite solar cells enabled by ionic liquid-bulky spacers

The crucial component,bulky spacers,in two-dimensional Ruddlesden-Popper(2 DRP)layered tin(Sn)perovskites are highly limited by halide ammonium salts,leading to the insufficient control of complex crystallization process due to the limited interaction between bulky spacers and 2 DRP perovskite frameworks.Here,we report an ionic liquid-bulky spacer,butylammounium acetate(BAAc O),for constructing efficient and stable 2 DRP Sn-based perovskite solar cells(PSCs).In contrast to the traditional halide ammonium bulky spacer,butylammounium iodide(BAI),the Ac O^(-)-functional group in BAAc O has a strong interaction with formamidine ions(FA^(+))and Sn2+.The inter-component interaction allows the formation of controllable intermediates for the favorable growth of smooth,dense,and highly oriented perovskite films.A PSC with power conversion efficiency of 10.36%(7.16%for BAI)is achieved,which is the highest report,along with improved stability with~90%retained after~600 h storage in N_(2) atmosphere without any encapsulation.

Leading order relativistic chiral nucleon-nucleon interaction

Motivated by the successes of relativistic theories in studies of atomic/molecular and nuclear systems and the need for a relativistic chiral force in relativistic nuclear structure studies, we explore a new relativistic scheme to construct the nucleon-nucleon interaction in the framework of covariant chiral effective field theory. The chiral interaction is formulated up to leading order with covariant power counting and a Lorentz invariant chiral Lagrangian.We find that the relativistic scheme induces all six spin operators needed to describe the nuclear force. A detailed investigation of the partial wave potentials shows a better description of the;S——0 and;P;phase shifts than the leading order Weinberg approach, and similar to that of the next-to-leading order Weinberg approach. For the other partial waves with angular momenta J≥1, the relativistic results are almost the same as their leading order non-relativistic counterparts.

Stable Metal–Halide Perovskite Colloids in Protic Ionic Liquid

Obtaining long-term stable and robust perovskite colloids solution remains an important scientific challenge due to the limited interaction between solvent and perovskite solutes.Here,we unveil the formation mechanism of chemically robust perovskite precursor solutions under ambient conditions using methylammonium acetate(CH3NH3•CH3COO,MAAc)protic ionic liquid(PIL)solvent.Tens of nanometers colloids are assembled on the molecular level via regular oriented gel-like lamellae with a mean thickness of 34.69 nm,width of 56.81 nm,and distance of 91.05 nm.