摘要：Origin of polarization sensitivity of photonic wire waveguides （PWWs） is analysed and the effective refractive indices of two different polarization states are calculated by the three-dimensional full-vector beam propagation method. We find that PWWs are polarization insensitive if the distribution of its refractive index is uniform and the cross section is square. An MRR based on such a polarization-insensitive PWW is fabricated on an 8-inch silicon-on-insulator wafer using 248-nm deep ultraviolet lithography and reactive ion etching. The quasi-TE mode is resonant at 1542.25nm and 1558.90nm, and the quasi-TM mode is resonant at 1542.12nm and 1558.94nm. The corresponding polarization shift is 0. 13 nm at the shorter wavelength and 0.04 nm at the longer wavelength. Thus the fabricated device is polarization independent. The extinction ratio is larger than 10dB. The 3dB bandwidth is about *** and the Qvalue is about 620 at 1558.90nm.

摘要：A new type of V-shaped photonic crystal fiber with elliptical air-holes is proposed to realize simultaneous high bire- fringence and nonlinearity at a wavelength of 1.55 μm. The full vector finite element method was adopted to investigate its characteristics, including birefringence, nonlinearity, and dispersion. The PCF exhibited a very high birefringence of 2.89x10-2 and very high nonlinear coefficient of 102.69 W-1 .km 1. In particular, there were two zero-dispersion wave- lengths （ZDWs） in the visible （X： 640-720 nm and Y： 730-760 nm） and near-infrared regions （X： 1050-1606 nm and Y： 850-1500 nm）. The combination of high birefringence and nonlinearity allowed the PCF to maintain the polarization state and generate a broadband super continuum, with potential applications in nonlinear optics.

摘要：The research on nanophotonic devices has made great progress during the past decades. It is the unremitting pursuit of researchers that realize various device functions to meet practical applications. However, most of the traditional methods rely on human experience and physical inspiration for structural design and parameter optimization, which usually require a lot of resources, and the performance of the designed device is limited. Intelligent algorithms, which are composed of rich optimized algorithms, show a vigorous development trend in the field of nanophotonic devices in recent years. The design of nanophotonic devices by intelligent algorithms can break the restrictions of traditional methods and predict novel configurations, which is universal and efficient for different materials, different structures, different modes, different wavelengths, etc. In this review, intelligent algorithms for designing nanophotonic devices are introduced from their concepts to their applications, including deep learning methods, the gradient-based inverse design method, swarm intelligence algorithms, individual inspired algorithms, and some other algorithms. The design principle based on intelligent algorithms and the design of typical new nanophotonic devices are reviewed. Intelligent algorithms can play an important role in designing complex functions and improving the performances of nanophotonic devices, which provide new avenues for the realization of photonic chips.

摘要：The geometric,electronic and optical properties of the graphene-like gallium nitride(GaN) monolayer paired with WS_2 or WSe_2 were studied systematically using the first-principles *** interacts with WS2 or WSe_2 via van der Waals interaction and all the most stable configurations of these two nanocomposites exhibit direct band gap ***,the type-Ⅱ heterojunctions are formed because the conduction band minimums and valence band maximums are respectively contributed by WS_2(or WSe_2) and *** imaginary parts of the dielectric function and the absorption spectra of the heterostructures were also calculated and the relatively improved optical properties were observed because of the new interband *** addition,the band offsets as well as the intrinsic electric fields resulting from the interlayer charge transfer indicate that the electron-hole pairs recombination can be effectively inhibited,which is conducive for the photocatalysis ***,the band gaps of the heterostructures can be modulated by applying biaxial strains and even shift away the conduction band edge potential from the H^+/H_2potential in a certain range,which further enhances the photocatalyst *** results indicate that GaN/WS2 or GaN/WSe_2 nanocomposites are good candidate materials for photocatalyst or photoelectronic applications.

摘要：最近,全无机铯铅溴(CsPbX_(3)(X=Cl,Br,I))钙钛矿纳米晶体被广泛应用于光催化CO_(2)还原(CO_(2)RR)领域.但是,由于纯CsPbX_(3)纳米晶体内部载流子辐射复合严重,所以精心设计基于CsPbX_(3)纳米晶体的异质结构对于分离载流子和实现高效的CO_(2)RR是非常重要的.本文中,我们介绍了利用光辅助的方法将Pd纳米颗粒锚定在CsPbX_(3)纳米晶体上.利用此方法所制备的CsPbBr_(3)@Pd纳米晶体通过在CsPbBr_(3)/Pd界面处构建肖特基结从而促进了载流子的分离并抑制了辐射复合.第一性原理计算表明:在CO_(2)RR过程中,CsPbBr_(3)@Pd纳米晶体比纯CsPbX_(3)纳米晶体具有更低的能量势垒.当CsPbBr_(3)@Pd纳米晶体被用作CO_(2)RR催化剂时,电子消耗速率高达46.2μmol g^(-1)h^(-1),是纯CsPbX_(3)纳米晶体作为光催化剂时电子消耗速率的4.8倍.这项工作不仅介绍了一种利用光辅助将钯纳米颗粒锚定在CsPbX_(3)纳米晶体上的方法,而且还证明了CsPbBr_(3)@Pd纳米晶体在光催化CO_(2)还原领域的巨大潜能.

摘要：The past decade has witnessed a surge of interest in exploring emergent particles in condensed matter *** particles,emerged as excitations around exotic band degeneracy points,continue to be reported in real materials and artificially engineered systems,but so far,we do not have a complete picture on all possible types of particles that can be ***,via systematic symmetry analysis and modeling,we accomplish a complete list of all possible particles in time-reversal-invariant *** includes both spinful particles such as electron quasiparticles in solids,and spinless particles such as phonons or even excitations in electric-circuit and mechanical *** establish detailed correspondence between the particle,the symmetry condition,the effective model,and the topological *** obtained encyclopedia concludes the search for novel emergent particles and provides concrete guidance to achieve them in physical systems.

摘要：铂(Pt)是质子交换膜燃料电池(PEMFCs)阳极氢氧化反应(HOR)中最先进的电催化剂.然而,Pt催化剂对CO(工业低成本氢燃料中的杂质)极度敏感从而中毒,这会引起器件性能的急剧衰退,导致器件运行成本高.因此,提高Pt催化剂的CO耐受性对PEMFCs的商业化推广至关重要.在此,我们设计合成了一种独特的PtNiW@WO_(x)核壳纳米线来提高Pt基催化剂对CO的耐受能力.机理研究表明,表面无定形的WO_(x)壳层可以作为分子围栏,在动力学上阻碍CO扩散到达Pt位点.在热力学上,Ni和W元素合金化产生的电子效应可以使Pt的d带中心降低,减弱CO在Pt位点上的化学吸附.此外,亲氧W元素可以加速水的解离,提供更多OH活性物种,促进CO的氧化脱附.因此,在1000ppm CO/H_(2)条件下,所设计的PtNiW@WO_(x)核壳纳米线催化剂表现出优异的HOR抗CO中毒性能,在4000 s后仍能保持超过90%的HOR电流密度,超过了原始的PtNi纳米线和目前报道的绝大多数Pt基催化剂.

摘要：The production of high-quality eco-friendly quantum dots(QDs)is challenging because of the efficient yet elusive nonradiative recombination *** study examined the effects of cooling engineering on regulating the excited states to realize high-quality ZnSeTe core-shell *** presence of ultrafast hot-carrier trapping and band-edge carrier trapping is responsible for the poor emission efficiency in ZnSeTe *** above processes can be suppressed simultaneously by engineering the cooling process,and the underlying mechanisms are interrogated by combined electronic and spectroscopic *** engineered ZnSeTe QDs exhibited record-high efficiency(>90%)and stability that were comparable to those of the canonical CdSe *** on the achievement,the ZnSeTe QD-based white light-emitting diodes(WLEDs)showed excellent optical performance,including a high color-rendering index of 80 and an appropriate correlated color temperature of 7391 ***,the WLEDs could serve as light sources in ecofriendly visible light *** results highlight the feasibility of eco-friendly QDs for practical applications without environmental hazards.

摘要：非稠环电子受体(NFREA)具有合成简单和结构修饰灵活的特点,是制备高性能低成本有机太阳电池(OSCs)的理想材料.本工作以不同侧链修饰的二氟苯并三氮唑(ffBTz)作为弱缺电子核(A’),分别设计合成了三种A-D-A’-D-A型NFREA,即ffBTz-BO、ffBTz-EH和ffBTz-C4.其中,ffBTz-EH,由于其合适的侧链长度,在分子结晶度和分子堆积优势取向之间取得了平衡,从而获得了更高的电荷迁移率.并且得益于高效的电荷传输和最合适的相分离形貌,基于ffBTz-EH的OSC获得12.96%的最高能量转换效率,这也是A-D-A’-D-A型NFREA获得的最高效率之一.本研究表明,A’核心上的烷基侧链在调节分子结晶度、活性层形貌和进一步调控器件性能方面起着至关重要的作用,这为未来设计高效低成本的A-D-A’-D-A型非稠环电子受体提供了思路.

摘要：Pseudocapacitors with high power density,longterm durability,as well as reliable safety,play a key role in energy conversion and *** electrode materials combing the features of high specific capacitance,excellent rate performance,and outstanding mechanical stability is still a ***,a facile partial sulfurization strategy has been developed to modulate the electronic structure and crystalline texture of cobalt hydroxide nanosheets(denoted as Co(OH)2)at room *** resultant cobalt hydroxysulfide nanosheet(denoted as Co SOH)electrode with abundant low-valence cobalt species and amorphous structure,exhibits a high specific capacitance of 2110 F g^-1at1 A g^-1with an excellent capability retention rate of 92.1%at10 A g^-1,which is much larger than that of Co(OH)2 precursor(916 F g^-1at 1 A g^-1 and 80%retention at 10 A g^-1).Furthermore,the fabricated asymmetric supercapacitor device constructed with Co SOH and active carbon displays a considerable high energy density of 44.9 W h kg^-1at a power density of 400 W kg^-1,and exceptional stability after 8000cycles.