Enhanced π–π Interactions of Nonfullerene Acceptors by Volatilizable Solid Additives in Efficient Polymer Solar Cells

Fine‐tuning of the nanoscale morphologies of the active layers in polymer solar cells (PSCs) through various techniques plays a vital role in improving the photovoltaic performance. However, for emerging nonfullerene (NF) PSCs, the morphology optimization of the active‐layer films empirically follows the methods originally developed in fullerene‐based blends and lacks systematic studies. In this work, two solid additives with different volatilities, SA‐4 and SA‐7, are applied to investigate their influence on the morphologies and photovoltaic performances of NF‐PSCs. Although both solid additives effectively promote the molecular packing of the NF acceptors, due to the higher volatility of SA‐4, the devices processed with SA‐4 exhibit a power conversion efficiency of 13.5%, higher than that of the control devices, and the devices processed with SA‐7 exhibit poor performances. Through a series of detailed morphological analyses, it is found that the volatilization of SA‐4 after thermal annealing is beneficial for the self‐assembly packing of acceptors, while the residuals due to the incomplete volatilization of SA‐7 have a negative effect on the film morphology. The results delineate the feasibility of applying volatilizable solid additives and provide deeper insights into the working mechanism, establishing guidelines for further material design of solid additives.     

New Beta-lactamases in Candidate Phyla Radiation: Owning Pleiotropic Enzymes Is a Smart Paradigm for Microorganisms with a Reduced Genome

The increased exploitation of microbial sequencing methods has shed light on the high diversity of new microorganisms named Candidate Phyla Radiation (CPR). CPR are mainly detected via 16S rRNA/metabarcoding analyses or metagenomics and are found to be abundant in all environments and present in different human microbiomes. These microbes, characterized by their symbiotic/epiparasitic lifestyle with bacteria, are directly exposed to competition with other microorganisms sharing the same ecological niche. Recently, a rich repertoire of enzymes with antibiotic resistance activity has been found in CPR genomes by using an in silico adapted screening strategy. This reservoir has shown a high prevalence of putative beta-lactamase-encoding genes. We expressed and purified five putative beta-lactamase sequences having the essential domains and functional motifs from class A and class B beta-lactamase. Their enzymatic activities were tested against various beta-lactam substrates using liquid chromatography-mass spectrometry (LC-MS) and showed some beta-lactamase activity even in the presence of a beta-lactamase inhibitor. In addition, ribonuclease activity was demonstrated against RNA that was not inhibited by sulbactam and EDTA. None of these proteins could degrade single- and double-stranded-DNA. This study is the first to express and test putative CPR beta-lactamase protein sequences in vitro. Our findings highlight that the reduced genomes of CPR members harbor sequences encoding for beta-lactamases known to be multifunction hydrolase enzymes.     

T型发射区单晶硅太阳电池的输出特性研究

利用TCAD半导体器件仿真软件对具有T型发射区结构的单晶硅太阳电池进行了仿真研究。全面系统地分析了在不同衬底少子寿命情况下,不同T型发射区深度对太阳电池外量子效率、短路电流密度、开路电压、填充因子及转换效率的影响。仿真结果表明:采用T型发射区结构可在一定程度上提高常规均匀发射区太阳电池的电学性能;T型发射区结构对700~1200nm长波段入射光的外量子效率具有明显的改善作用;当衬底少子寿命一定时,太阳电池短路电流密度、填充因子均随T型发射区深度的增大而增大,而开路电压随T型发射区深度的增大而减小;当T型发射区深度大于80μm时,对于低衬底少子寿命的单晶硅太阳电池,T型发射区结构对其转换效率的改善效果最为显著。     

Recombination luminescence from defects in boron-ion implantation-doped diamond using low fluences

 Two identical, high purity, natural type IIa diamonds, which displayed the ubiquitous blue cathodoluminescence (CL) band at ≈ 2.9 eV, as well as an indication of the corresponding green band at ≈ 2.4 eV, have been equivalently doped by using extremely low dose B⁺- and C⁺-ion CIRA-implantations respectively. Comparative CL measurements showed changes in the intensities of the 2.9 and 2.4 eV bands and the generation of bands at ≈ 4 eV, as well as at ≈ 3.5 and ≈ 4.6 eV (the latter two in the B⁺-CIRA diamond). The results are commensurate with the model (proposed previously) in which the 2.9 and 4 eV bands are generated respectively by electron-hole recombinations at negatively charged acceptor- and positively charged donor-like, intrinsic defects. The present results indicate that Coulomb interactions between the latter defects and (at least partially) compensated, negatively charged, boron acceptors, generate the 3.5 and 4.6 eV bands, which may be considered as higher energy (≈ 0.6 eV) replicas of the 2.9 and 4 eV bands. In both cases, two electrons and a hole interact just before the hole combines with an electron. Such a configuration of charges seems related to, and could possibly be described as, a type of ”ionised exciton molecule”, where the ”bonding” of two negative ”nuclei” is facilitated by the presence of the hole. The CL measurements further indicate that the 2.4 eV band forms when a high enough density of, in this case, neutral acceptors are present. These neutral acceptors compete with the valence band to supply holes for recombination at the negatively charged, acceptor-type, intrinsic defects which are, in the absence of the boron, responsible for the generation of the blue, 2.9 eV band. Received: 5 December 1997 / Accepted: 13 December 1997     

声学-结构设计灵敏度分析

声学 -结构设计灵敏度分析揭示了结构振动引起的辐射声压与结构设计变量之间的关系。分别用有限元法和边界元法计算结构设计灵敏度和声学灵敏度。将两个灵敏度结合得到最终的声学 -结构设计灵敏度。在边界元计算中 ,采用退化元处理奇异积分问题 ,对特征频率不唯一问题采用CHIEF方法处理。以脉动球和箱体为例 ,验证了算法的可行性和精确性。     

Grain‐Boundary “Patches” by In Situ Conversion to Enhance Perovskite Solar Cells Stability

The power conversion efficiency of organic–inorganic hybrid perovskite solar cells has increased rapidly, but the device stability remains a big challenge. Previous studies show the grain boundary (GB) can facilitate ion migration and initiate device degradation. Herein, methimazole (MMI) is employed for the first time to construct a surface “patch” by in situ converting residual PbI₂ at GBs. The resultant MMI–PbI₂ complex can effectively suppress ion migration and inhibit diffusion of the metal electrodes. The origin of the surface “patch” effect and their working mechanisms are investigated experimentally and theoretically at the microscopic level. It hence demonstrates a simple and effective method to prolong the device stability in the context of GB engineering, which could be extensively applied to perovskite‐based optoelectronics.     

基于阈值滤波的太阳能智能追踪系统设计

针对太阳能利用率不高的现状,设计了以MSP430F169单片机为核心的智能型太阳能自动追踪系统,采用基于阈值滤波的最大功率点追踪控制算法,提高了系统太阳能板追踪太阳的灵敏度,采用风速监测模块,增强了系统的稳定性。结果表明,相比固定电池板,系统吸收太阳能的转换效率提高了约95%,对提高太阳能的吸收效率,合理地利用太阳能具有重要的研究价值。     

辐射限制下有源无源协同跟踪技术

为了提高作战飞机的隐蔽性,提出了一种辐射限制下有源无源传感器目标跟踪与协同管理的方法,给出了基于辐射控制的机载多传感器系统协同跟踪方法.利用跟踪过程中目标残差范数与门限的比较结果,判断雷达开关机,用序贯和IMM(interacting multiple model)联合滤波算法对目标进行跟踪.对利用该方法的机载多传感器目标跟踪性能进行了仿真分析,仿真结果证明了该方法的合理性和有效性.