手性钙钛矿的结构维度与光电特性

近十年,有机无机杂化钙钛矿凭借其新颖优异的光电特性而引起广泛关注。最近,手性钙钛矿由于结合了钙钛矿材料和手性材料各自独特性能,在三维显示、光学信息处理、量子光学、生物探测、自旋电子等方面具有重要应用价值。根据有机、无机组分的空间分布,可以对手性钙钛矿的结构维度进行分类。本文以手性钙钛矿的不同结构维度为出发点,分别阐述了一维、二维和三维手性钙钛矿的晶体结构、光学和光电特性,包括圆二色性、圆偏振光致发光和光电探测等特性。考虑到二维手性钙钛矿具有独特的范德华层状晶体结构,重点介绍了其与其它二维材料组合成二维异质结构方面的工作。最后,分别从材料制备和器件应用的角度,总结了手性钙钛矿的重点挑战问题和未来发展方向。     

PTFE基微波覆铜板中FEP含量对孔隙率的影响

高频通信采用的微波高频覆铜板在制作材料的选用时,需要小的介电常数和介电损耗,一般采用PTFE (聚四氟乙烯)作材料,PTFE不沾任何材料且具有较大的热膨胀系数,混入FEP (聚四氟乙丙烯)到PTFE乳液中可以改善不沾任何材料的性质,玻璃纤维布可以改善热膨胀系数大的问题,但是会造成乳液和玻璃纤维之间有空隙。试验研究发现,当FEP含量占乳液30%时,pp片(半固化片)中乳液和玻璃纤维之间的孔隙率达到较小的水平。本实验采用介电损耗(Df)和介电常数(Dk)的比值代表孔隙率的水平,数值越小,表示孔隙率越小。     

Room-temperature ferromagnetism observed in Nd-doped In_2O_3 dilute magnetic semiconducting nanowires

Nd-doped In_2O_3 nanowires were fabricated by an Au-catalyzed chemical vapor deposition method.Nd atoms were successfully doped into the In_2O_3 host lattice structure,as revealed by energy dispersive x-ray spectroscopy,x-ray photoelectron spectroscopy,Raman spectroscopy,and x-ray diffraction.Robust room temperature ferromagnetism was observed in Nd-doped In_2O_3 nanowires,which was attributed to the long-range-mediated magnetization among Nd~(3+)-vacancy complexes through percolation-bound magnetic polarons.     

Tuning of the Magnetic Damping Parameter by Varying Cr Composition in Fe_(1-x)Cr_x Alloy

We investigate the magnetic damping parameter of Fe_1-xCr_x thin films using the time-resolved magneto-optical Kerr effect technique.It is demonstrated that the overall effective damping parameter is enhanced with the increasing Cr concentration.The effective damping at high field α₀ is found to be significantly enhanced when increasing the Cr concentration with the α₀=0.159 in the Fe₄₅Cr₅₅ enhanced by 562% compared with that of α     

FEP含量对PTFE基高频PCB覆铜板性能的影响

主要介绍制备微波高频PCB覆铜板时,PTFE树脂中FEP乳液体积浓度对浸渍玻纤布树脂含量的影响,以及对制作的pp(Pre-pregnant)介电常数(Dk)和介电损耗(Df)的影响。试验显示,随着树脂中FEP乳液含量的增加,浸渍玻纤布树脂百分比降低,而Dk和Df值升高,用pp所制作PCB覆铜板的铜箔剥离强度随着FEP乳液含量的升高而增大。