Temperature stable (1-x)NaCa4V5O17-xBaV(2)O(6) microwave dielectric ceramics for ULTCC applications
CERAMICS INTERNATIONAL
Authors: Pei, Cuijin; Li, Yang; Tan, Jingjing; Yao, Guoguang; Jia, Yanmin; Liu, Weihong; Liu, Peng; Zhang, Huaiwu
Abstract
Novel temperature stable (1-x)NaCa4V5O17-xBaV(2)O(6) (0.8 <= x <= 0.9, (1-x)NCV-xBV) ceramics were successfully synthesized through a high-temperature solid phase reaction route. XRD and SEM-EDS analysis demonstrated that only NaCa4V5O17 and BaV2O6 phases were formed without any extra phase. The introduction of BaV2O6 not only effectively improved the tf of NaCa4V5O17 matrix but also considerably lowered its sintering temperature to 550 degrees C. Typically, an approximate-zero tau(f) value around -1.0 ppm/degrees C was achieved for 550 degrees C sintered 0.12NCV0.88BV ceramics with low epsilon(r) of 10.9 and Qxf of 15,500 GHz (at 10.3 GHz). Its good compatibility with Al electrode furthermore made 0.12NCV-0.88BV composites suitable for ULTCC applications.
Enhancing the Performance of Organic Solar Cells by Prolonging the Lifetime of Photogenerated Excitons
ADVANCED MATERIALS
Authors: Guo, Qingxin; Liu, Yahui; Liu, Ming; Zhang, Hao; Qian, Xiquan; Yang, Jinjin; Wang, Jing; Xue, Wenyue; Zhao, Qian; Xu, Xinjun; Ma, Wei; Tang, Zheng; Li, Yunliang; Bo, Zhishan
Abstract
Exciton lifetime (tau) is crucial for the migration of excitons to donor/acceptor interfaces for subsequent charge separation in organic solar cells (OSCs); however, obvious prolongation of tau has rarely been achieved. Here, by introducing a solid additive 9-fluorenone-1-carboxylic acid (FCA) into the active layer, which comprises a nonfullerene acceptor, 3,9-bis(2-methylene-((3-(1,1-dicyanomethylene)-6/7-methyl)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2 ',3 '-d ']-s-indaceno[1,2-b:5,6-b ']dithiophene (IT-M), tau is substantially prolonged from 491 to 928 ps, together with obvious increases in fluorescence intensity and quantum yield. Time-resolved transient infrared spectra indicate the presence of an intermolecular vibrational coupling between the electronic excited state of IT-M and the electronic ground state of FCA, which is first observed here and which can suppress the internal conversion process. IT-M-based OSCs display an improved short-circuit current and fill factor after the addition of FCA. Thus, the power conversion efficiency is increased, particularly for devices with a large donor/acceptor ratio of 1:4, whose efficiency is increased by 56%. This study describes a novel method, which is also applicable to other nonfullerene acceptors, for further improving the performance of OSCs without affecting their morphology and light absorption properties.
COA
Publication 
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