Aqueous-processed insulating polymer/nanocrystal solar cells with effective suppression of the leakage current and carrier recombination

As one of the most environmentally friendly photovoltaic(PV) conversion equipments,aqueousprocessed CdTe nanocrystal solar cells(NC SCs) have attracted great interest in recent years because of their excellent properties such as high charge-carrier mobility and broad absorption.However,two issues including interfacial recombination and leakage current seriously restrict their performance.In this paper,insulating polymer poly(vinyl pyrrolidone)(PVP) is introduced into CdTe NC SCs to solve the problems.The experimental results of transmission electron microscopy(TEM),atomic force micro scopy(AFM) and dark current measurements,etc.,demonstrate the leakage current is effectively suppressed by introducing PVP.Through further designing device structure,the reduction of interfacial recombination after introducing PVP is confirmed.By strategically taking the advantages of PVP properties(e.g.,water solubility and thermostability),the power conversion efficiency of the devices with PVP is enhanced by almost 37% compared to pure CdTe devices.This work demonstrates an effective and low-cost method to fabricate NC SCs via aqueous route.Moreover,it also proves that appropriate content of insulating polymer is of beneficial in promoting the PV performance.     

基于荧光光谱技术的菜籽油氧化状态智能评价

菜籽油在加工及贮藏过程中，易受氧气、温度、光照等因素的影响，产生氧化酸败现象。为准确判断油脂氧化程度，实现不同氧化模式下菜籽油品质的快速判别，采用三维同步荧光光谱技术结合平行因子分析法及BP神经网络法建立菜籽油氧化状态的智能评价模型。以冷榨菜籽油为原料，将样品分别置于常温、Schaal烘箱、高温模式中氧化处理，期间采集菜籽油的三维同步荧光光谱数据及理化指标，当理化指标超出国标限定范围时，停止采集数据。结果表明，菜籽油中荧光物质在不同氧化模式中的演变规律呈显著差异，氧化温度对菜籽油荧光光谱有明显影响。常温氧化350 d与第1 d相比，菜籽油的特征荧光峰位置无变化，仅在激发波长Ex为620和660 nm附近荧光峰强度发生微弱变化；Schaal烘箱氧化26 d后，在激发波长Ex为620和660 nm附近荧光峰强度显著减弱，且在激发波长Ex为350～450 nm之间有新的荧光峰生成；高温氧化48 h后，Ex为620和660 nm处荧光峰消失，在Ex为400～550 nm处产生显著荧光峰，相对Schaal烘箱氧化，荧光波长发生一定程度红移，这是由于高温氧化过程中油脂氧化生成的物质稳定性较差引起的。利用平行因子分析法对三维同步荧光光谱数据进行分解获取有效的二维荧光光谱数据，当组分数为6，Δλ=60 nm时激发波长的载荷值最大，不同样品间差异最显著。选定Δλ=60 nm波段的二维荧光光谱数据用于智能评价，作为BP神经网络模型的输入值，以极性组分作为模型输出值，分别对菜籽油三种氧化模式数据建模训练。实验结果表明，三种氧化模式对应的训练集、验证集、测试集模型相关系数r均能达到0.9以上，其中常温氧化模式中验证集及测试集模型的相关系数r为1，输出值与目标值较接近，模型的预测效果较好；综合三种氧化模式数据建模，对应训练集、验证集、测试集模型的相关系数分别为0.999，0.913和0.988，均方误差均较小，说明该模型能准确判断菜籽油的不同氧化状态。因此，三维同步荧光光谱技术结合平行因子分析法、BP神经网络法建立快速检测模型能实现菜籽油不同氧化状态的判别，为菜籽油的氧化程度的评价提供新方法，同时为其他食用油的品质评价提供参考。     

High-efficiency circularly polarized emission from liquid-crystalline platinum complexes

Realizing both a high emission efficiency and luminescence dissymmetry factor (g_lum) in circularly polarized solution processable organic light-emitting diodes (CP-OLEDs) remains a significant challenge. In this contribution, two chiral phosphorescent liquid crystals based on cyclometalated platinum complexes are prepared, in which the chiral s-2-methyl-1‑butyl group is introduced into the cyclometalating ligand and the mesogenic fragment is attached to the periphery of the ancillary ligand. The platinum complexes exhibit both smectic and chiral nematic phases as evidenced by polarized optical microscopy, differential scanning calorimetry and small-angle X-ray diffraction. Remarkably, a high photoluminescent quantum efficiency of over 78% and clear circularly polarized luminescent signal with g_PL of about 10^–2 are observed for the complexes. Further, solution-processed CP-OLEDs show maximum external quantum efficiencies (EQE) of over 15% and strong circularly polarized electroluminescent signals with a g_EL ≈ 10^–2. This research demonstrates that both liquid crystallinity and the number of chiral centers play key roles in improving the chiroptical property, paving the way for a new approach for the design of high-efficiency CPL emitters.     

焙烧温度对LaSrFeMo0.9Co0.1O6催化剂催化甲烷燃烧性能的影响

采用溶胶凝胶法制备LaSrFeMo0.9Co0.1O6,以催化甲烷燃烧为目标反应,研究不同焙烧温度(600、700、800、900℃)对其催化甲烷燃烧性能的影响.通过XRD、BET、H2-TPR及SEM技术对其结构进行表征.结果表明,在不同的焙烧温度下均可形成完整的双钙钛矿晶型,且焙烧温度不同其催化活性不同,随着焙烧温度的升高其催化活性先升高后逐渐降低.当焙烧温度为800℃,样品比表面积为14 m2/g,起燃温度T10％为428℃,T90％为640℃.     

Notes on Automorphisms of Prime Rings

Let R be a prime ring, L a noncentral Lie ideal and σ a nontrivial automorphism of R such that usσ(u)ut= 0 for all u ∈ L, where s, t are fixed non-negative integers. If either char R s + t or char R = 0, then R satisfies s4, the standard identity in four variables. We also examine the identity(σ([x, y])-[x, y])n=0 for all x, y ∈ I, where I is a nonzero ideal of R and n is a fixed positive integer. If either char R n or char R = 0, then R is commutative.     

Mitochondria-targeted fluorescent probe based on vibration-induced emission for real-time monitoring mitophagy-specific viscosity dynamic

Directly monitoring mitophagy-specific viscosity dynamic in living cells is of great significance but remains challenging. Herein, this study reported a novel mitochondria-targeted fluorescent probe DPAC-DY based on vibration-induced emission (VIE) for monitoring viscosity changes during mitochondrial autophagy. This probe contained N,N'-diphenyl- dihydrodibenzo[a,c]phenazine (DPAC) as the VIE core and two positively charged pyridinium moieties for mitochondria anchoring. As the ambient viscosity increased, the vibration of DPAC-DY could be hindered, and subsequently resulting in the enhancement of fluorescence emission. In vitro and intracellular experiments indicated that the probe DPAC-DY showed highly sensitive response to viscosity due to VIE mechanism. Importantly, by virtue of this probe, in situ and real-time visualization of the specific viscosity dynamics during the mitochondrial autophagy process was achieved. Thus, this work provides a novel strategy for VIE-based viscosity response sensors applied to specific organelles and offers a platform for in-depth study of mitochondrial viscosity-related diseases.     

Sonozonation: Enhancing the antimicrobial efficiency of aqueous ozone washing techniques on cherry tomato

Ultrasound requires high power and longer treatment times to inactivate microorganisms when compared to ultrasound combined with other technologies. Also, the antimicrobial efficiency of aqueous ozone increases with an increase in its concentration and exposure time, but with a detrimental effect on the quality of the treated food. In this study, the effect of aqueous ozone at low concentration, multi-mode frequency irradiation and their combination on microbial safety and nutritional quality of cherry tomato was investigated. Individual washing with aqueous ozone and mono-mode frequency irradiation resulted in <1 log CFU/g reduction in the spoilage microorganisms, while dual-mode frequency irradiation (DMFI) resulted in higher microbial reduction (1.3–2.6 1 log CFU/g). The combined system (20/40 kHz + aqueous ozone) on the other hand, resulted in >3 log CFU/g microbial reduction. The application of DMFI enhanced the antimicrobial efficiency of aqueous ozone without any detrimental effect on the physicochemical properties (except the firmness), bioactive compounds, and antioxidants of the cherry tomato during 21 days refrigerated storage. The result obtained indicates the promising substitute to the single washing technique for microbial safety as well as preserving the nutritional quality and enhancing the shelf life of cherry tomato.     

Molecular simulation study on the self-assembly behaviors of zwitterionic heterogemini surfactant in aqueous solution

The self-assembly behaviors of a series of zwitterionic heterogemini surfactants C_mH_2m+1-PO^4–(CH₂)₂-N⁺(CH₃)₂-C_nH_2n+1, abbreviated as C_m-P-N-C_n (m, n?=?9, 9; 9, 12; 9, 15; 9, 18; 12, 12; 12, 15; 12, 18; 15, 15; 15, 18; 18, 18), have been investigated in aqueous solution by the dissipative particle dynamics (DPD) method. Morphologies such as sphere (S), rod (R), planar grid (PG), lamella (L), honeycomb (H), one-, two-, and three-dimensional tunnels (1DT, 2DT, and 3DT) have been observed showing more diversities than those of the corresponding symmetric gemini surfactants C_m-N-N-C_m (m?=?9, 12, 15, 18). With the increase of surfactant concentration in the aqueous solution, a distinct transition path ‘‘S—R—PG—3DT—L—2DT—1DT’’ is proved to be common for all the C_m-P-N-C_n systems. Besides, the hydrophobic chain length has a significant influence on the self-assembly behaviors in the case of m?≠?n. Radial distribution function is an effective method to quantitatively evaluate the interaction and relationship between each functional group in the surfactant molecule and water. Results can provide a new insight into the self-assembly behaviors of zwitterionic heterogemini surfactants and the corresponding applications.     

Syntheses, Crystal Structures and Properties of Two Supramolecules Assembled from Weak Interactions

Two complexes, [Cu2(Htdb)4(H2O)2] (1) and [Cd(bipy)2(Hmcmbc)2] (2) (H2tdb = 2,2-thiodibenzoic acid, H2mcmbc = m-(carboxyl-methyloxy)-benzenecarboxylic acid, bipy = 4,4'-bipyridine), have been prepared, and were characterized by elemental analysis, FT-IR and single-crystal X-ray diffraction. Structures indicate that complex 1 is a single molecule, and 2 is a one-dimensional chain. Their two-and three-dimensional frameworks are constructed through hydrogen bonding, π…π or C–H…π stacking, and such other weak interactions. The cyclic voltametric behavior of complex 1 and luminescence property of complex 2 were investigated. 1 belongs to the triclinic system, space group P with a = 7.8607(6), b = 11.7619(9), c = 15.3481(12) , α = 109.3670(10), β = 92.4420(10), γ = 92.0450(10)°, V = 1335.65(18) 3, Mr = 1256.26, Dc = 1.5619(2) g/cm3, F(000) = 642, μ = 1.029 mm–1, Z = 1, the final R = 0.0289 and wR = 0.0763 for 5199 observed reflections with I > 2σ(I). Complex 2 crystallizes in triclinic, space group P with a = 9.6378(10), b = 9.7508(10), c = 19.055(2) , α = 88.7020(10), β = 80.5260(10), γ = 69.2000(10)o, V = 1649.9(3) 3, Mr = 815.07, Dc = 1.641 g/cm3, μ = 0.732 mm-1, F(000) = 828, Z = 2, the final R = 0.0511 and wR = 0.1149 for 4729 observed reflections (I > 2σ(I)).     

镉(Ⅱ)磺基水杨酸配合物的合成、结构和荧光性质

配体2,2′-联吡啶(bipy)、磺基水杨酸(H2hssal)和镉盐反应合成了配合物[Cd(hssal)(bipy)(H2O)2]·H2O(1),用单晶X-射线和元素分析对生成的晶体进行了表征,结构研究发现该晶体属于单斜晶系P21/c空间群。Cd(Ⅱ)采取八面体配位几何构型,磺基水杨酸作为二齿桥联配体连结不同的Cd(Ⅱ)原子形成一维链结构,一维链被O-H…O氢键连接形成二维层,再进一步由O-H…O氢键将二维层联结在一起形成三维结构。研究了配合物1的荧光性质。CCDC:772715。