Systematic investigation of benzodithiophene- and diketopyrrolopyrrole-based low-bandgap polymers designed for single junction and tandem polymer solar cells

The tandem solar cell architecture is an effective way to harvest a broader part of the solar spectrum and make better use of the photonic energy than the single junction cell. Here, we present the design, synthesis, and characterization of a series of new low bandgap polymers specifically for tandem polymer solar cells. These polymers have a backbone based on the benzodithiophene (BDT) and diketopyrrolopyrrole (DPP) units. Alkylthienyl and alkylphenyl moieties were incorporated onto the BDT unit to form BDTT and BDTP units, respectively; a furan moiety was incorporated onto the DPP unit in place of thiophene to form the FDPP unit. Low bandgap polymers (bandgap = 1.4-1.5 eV) were prepared using BDTT, BDTP, FDPP, and DPP units via Stille-coupling polymerization. These structural modifications lead to polymers with different optical, electrochemical, and electronic properties. Single junction solar cells were fabricated, and the polymer:PC(71)BM active layer morphology was optimized by adding 1,8-diiodooctane (DIO) as an additive. In the single-layer photovoltaic device, they showed power conversion efficiencies (PCEs) of 3-6%. When the polymers were applied in tandem solar cells, PCEs over 8% were reached, demonstrating their great potential for high efficiency tandem polymer solar cells.     

硅基二氧化硅厚膜材料的快速生长

采用火焰水解法在Si片上快速淀积SiO₂厚膜材料,材料膜厚达到40μm以上,生长速率达8μm/min.然后将该材料分别在真空中/空气气氛中高温致密化处理,获得了各种形态的二氧化硅厚膜材料,包括平整度好、光滑透明的玻璃态SiO₂厚膜材料.并利用XRD、电子显微镜等仪器对SiO₂膜的表面和膜厚进行了测试分析.     

Fabrication and characteristics of character1 shaped reduced diameter polarization-maintaining optical fiber

A novel structure reducing diameter polarization maintaining optical fiber with high birefringence and strength is introduced.The fiber is fabricated through using modified chemical vapor deposition (MCVD) method,which is able to produce the optimum predicted character-1 shaped fiber structure.As a result,a low-loss fiber with beat length close to 2.0 mm at 1310 nm wavelength and extinction ratio approximately-25 dB has been produced.The process is both simple and reproducible.     

Cationic Chalcogenoviologen Derivatives for Photodynamic Antimicrobial Therapy and Skin Regeneration

A series of water-soluble cationic chalcogenoviologen-based photosensitizers for photodynamic antimicrobial therapy (PDAT) is reported. The Se-containing derivatives (SeMV²⁺) 5 b and 6 b showed good antimicrobial activities due to the presence of chalcogen atoms and a cationic scaffold. The former efficiently enhanced the generation of reactive oxygen species (ROS), and the latter facilitated the ROS delivery to bacteria, resulting in their death. Interestingly, alkyl-modified photosensitizers showed higher antimicrobial activities than commonly reported photosensitizers with quaternary ammonium (QA) groups. In particular, the SeMV²⁺ ( 6 b ) with excellent antibacterial activities efficiently promoted the healing of infected wounds in mice. Simple yet novel, nontoxic and biocompatible chalcogenoviologens provided a promising strategy to develop new efficient photosensitizers for photodynamic antimicrobial therapy and skin regeneration.     

Aeroelastic modeling of wind loading on a cable-net supported glass wall

Wind loading study on a cable-net supported glass wall is conducted by means of wind tunnel tests. An equiva- lent aeroelastic model is designed and constructed. Response of displacements of the wall is measured and analyzed. In order to design a glass wall under wind loading, the ＂wind- vibration factor＂ is estimated and discussed. In fact, the mech- anism of wind acting on the wall is commonly known not only as positive pressure, but also as negative pressure caused by the flow separation on the corners of the building. Due to the diffidence in the mechanism of wind acting, two typi- cal response cases are classified. The results show that the dynamic response of the structure caused by the negative pressure is stronger than that of the positive pressure case. To determine the aerodynamic wind loading on a flexible part of structure on a building, wind tunnel study may be useful and play an important role.     

Subarea law of entanglement in nodal fermionic systems

We investigate the subarea-law scaling behavior of the block entropy in bipartite fermionic systems which do not have a finite Fermi surface. It is found that in gapped regimes the leading subarea term is a negative constant, whereas in critical regimes with point nodes the leading subarea law is a logarithmic additive term. At the phase boundary that separates the critical and noncritical regimes, the subarea scaling shows power-law behavior.     

利用机器学习靶向设计先进电催化剂

随着能源需求增长与化石燃料资源枯竭之间的矛盾日益突出,以及石油、天然气等不可再生资源的燃烧带来的环境问题和全球变暖,清洁可再生能源越来越受到人们的重视.因此,包括能源转换和可逆能源使用等的可持续发展技术受到广泛关注.其中,电催化被认为是清洁能源转化的重要方法.目前,电催化反应的催化剂仍以贵金属为主.但贵金属昂贵的价格极...     

基于光纤Bragg光栅的温度传感实验

本文主要对光纤Bragg光栅的温度传感特性进行了理论分析,并通过实验,验证了光纤Bragg光栅反射波长与温度的线性变化关系,根据测量数据拟合出反射波长与温度之间的变化曲线。实验结果表明:光纤光栅对温度非常敏感;具有很好的线性度;辅助伸缩材料提高了光纤Bragg光栅温度传感器的灵敏度:其适合做温度传感器。     

脂质响应型探针用于动脉粥样硬化成像及治疗的研究进展

动脉粥样硬化是心血管疾病的主要威胁之一, 可能导致如急性心肌梗死在内的急性冠状动脉综合征、 卒中, 甚至猝死等一系列严重的不良后果. 脂质的异常积累是动脉粥样硬化的标志之一, 有必要观察它们在体内的数量、 定位和分布. 荧光探针具有可操作性强、 高时空分辨率和与活体生物相容性佳的优点, 有望成为了解动脉粥样硬化中的脂质功能的有利工具. 本文综合评述了基于罗丹明、 香豆素、 氟化硼二吡咯(BODIPY)、 1,8-萘酰亚胺等有机框架结构以及金属配合物的脂滴特异性光学成像探针的研究进展, 并重点介绍了其在动脉粥样硬化斑块成像、 手术导航及治疗等领域的应用. 最后, 对该研究领域进行了总结和展望, 希望可为相关研究提供有益参考.     

Narrow‐Bandgap Chalcogenoviologens for Electrochromism and Visible‐Light‐Driven Hydrogen Evolution

A series of electron‐accepting chalcogen‐bridged viologens with narrow HOMO–LUMO bandgaps and low LUMO levels is reported. The optoelectronic properties of chalcogenoviologens can be readily tuned through heavy atom substitution (S, Se and Te). Herein, in situ electrochemical spectroscopy was performed on the proof‐of‐concept electrochromic devices (ECD). E‐BnV²⁺ (E=Se, Te; BnV²⁺=benzyl viologen) was used for the visible‐light‐driven hydrogen evolution due to the strong visible‐light absorption. Remarkably, E‐BnV²⁺ was not only used as a photosensitizer, but also as an electron mediator, providing a new strategy to explore photocatalysts. The higher apparent quantum yield of Se‐BnV²⁺ could be interpreted in terms of different energy levels, faster electron‐transfer rates and faster formation of radical species.