High performance thermal-treatment-free tandem polymer solar cells with high fill factors

It is an effective way to enhance device performance of polymer solar cells (PSCs) by using a tandem structure that combines two or more solar cells. For tandem PSCs, the buffer layer plays an important role in determining the device performance. The most commonly used buffer layers, such as PEDOT:PSS, TiO_x, and ZnO, need thermal treatments that are not beneficial for reducing the fabrication complexity and cost of tandem PSCs. It is necessary to develop tandem PSCs fabricated by a thermal-treatment-free process. In this paper, we report high performance thermal-treatment-free tandem PSCs by developing PFN as buffer layers for both subcells. A power conversion efficiency (PCE) of 10.50% and a high fill factor of 72.44% were achieved by stacking two identical PTB7:PC₇₁BM subcells. When adopting a rear PTB7-Th:PC₇₁BM subcell, the highest PCE of 10.79% was further obtained for the tandem devices. The thermal-treatment-free process is especially applicable to flexible devices, in which plastic substrates are usually used.     

SR软件路由器的设计与实现

分段路由(segment routing,SR)是近几年IETF提出的一种路由机制,其目的是使IP/MPLS网络面向服务并且更高效.SR减少现有MPLS网络控制平面复杂的协议(LDP/RSVP-TE),并实现流量工程等机制.与基于RSVP的显式路径中隧道中间节点维护报文流的状态不同,基于SR的显式路径只在入口边界路由器中维护报文流的状态,从而提高了网络的可扩展性,因此SR对于下一代互联网具有重要的研究意义.对SR的实现机制进行了研究,利用软件路由平台Click,对基于PCE架构的SR控制平面子系统和基于MPLS的SR数据平面子系统的各个模块进行实现,并在实际中进行部署,以验证SR软件路由器的可行性.     

无源RFID应答器的改进电荷泵设计

提出了一种适用于ISO/IEC 18000-6C标准的无源RFID(射频识别)应答器的改进电荷泵.该设计基于导通角的概念分析能量转化效率.整个结构包含主电荷泵和偏置电路,通过二极管连接的MOS管抑制负载来提升偏置电压,并调节偏置电压有效抑制反向漏电流,消除了传统电荷泵中的阈值损失.该电荷泵采用0.35μm CMOS工艺...     

低碱冷冻预处理对棉织物活性染料DMSO/PCE染色性能的影响

棉织物在二甲基亚砜/四氯乙烯(DMSO/PCE)染色体系中用C.I.活性红48染色,探讨了低碱冷冻预处理温度、时间和碱质量分数对上染率、固色率和织物强力的影响,同时研究了染色时棉织物上水和碱含量在纤维相和溶剂相分布的变化对染料上染率和固色率的影响。结果表明:低碱冷冻预处理能够提高棉纤维的可及度;经最佳条件(氢氧化钠质量分数8%、温度-10°C、冷冻2h)预处理的棉织物在DMSO/PCE体系中水和碳酸钠的含量均有不同程度的提高,C.I.活性红48上染率变化不大,固色率提高约3%,经、纬向撕破强力相比于未处理棉织物分别提高45%和20%。     

Formation of charge‐transfer complexes significantly improves the performance of polymer solar cells based on PBDTTT‐C‐T: PC71BM

By adding appropriate proportions of nitrobenzene (C₆H₅NO₂) to the blended solution of poly{[4,8‐bis‐(2‐ethyl‐hexyl‐thiophene‐5‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl]‐alt‐[2‐(2′‐ethyl‐hexanoyl)‐thieno[3,4‐b]thiophen‐4,6‐diyl]}:[6,6]‐phenyl‐C71‐butyric acid methyl ester (PBDTTT‐C‐T: PC₇₁BM), we substantially improved the power conversion efficiency from the best reported value of 7.48–8.88%. Experiments and simulations show that nitrobenzene and PBDTTT‐C‐T form stable coplanar charge‐transfer complexes through hydrogen bonds. Formation of the PBDTTT‐C‐T‐C₆H₅NO₂ complex simultaneously increases the external quantum efficiency. The underlying mechanisms of increased external quantum efficiency are attributed to the following: (i) higher lowest unoccupied molecular orbital (LUMO) of PBDTTT‐C‐T‐C₆H₅NO₂ for more efficient photoinduced electron transfer to the LUMO of PC₇₁BM and (ii) efficient quenching of fluorescence in the active layers due to formation of the PBDTTT‐C‐T‐C₆H₅NO₂ complex. This discovery clearly illustrates the potential of hydrogen‐bonded complexes as a new route for efficient polymer‐based photovoltaic devices. Copyright © 2014 John Wiley & Sons, Ltd.     

多域光网络中考虑域间输出策略的分段共享保护算法

研究了多域光网络中的路由保护问题.在多域光网络中,域间路由的建立要遵从域间输出策略.在考虑域间输出策略的基础上提出了一种多域光网络中基于路径计算单元的分段共享保护算法.仿真表明,相比传统的基于路径计算单元的多域分段保护算法,该算法阻塞率低,平均保护切换时间短.     

Web服务事务处理模型研究

Web服务的出现对分布式事务提出了新的挑战,为了保证多个Web服务交互获得正确的执行和一致性的结果,必须为Web服务提供事务机制。该文提出了一个Web服务事务处理模型,研究了二阶段提交扩展协议、协调算法和事务补偿。该模型在事务处理过程中具有一定的实用性和灵活性,为Web服务投入跨企业的商业应用提供了有力的支持。