异质铝/金二聚物和三聚物中的等离子耦合性质

采用时域有限差分方法研究了异质铝/金二聚物和铝/金/铝纳米线三聚物的光学性质.首先研究了二聚物和三聚物的间距对透射谱和电场分布的影响,发现随着间距的增大,原短波长透射峰增强,并在间距大到一定程度时,发生分裂现象,而长波长透射峰在这个过程中单调红移.通过分析电场分布,我们发现分裂的峰之一是一种新的等离子耦合模式.另外,我们也分析了半径变化和金线偏移中心量对三聚物透射谱的影响,其中左侧铝线的半径变小会使近红外和红外区域的两个峰合并,而金线半径变小却会使它们两个峰分裂得更明显;另外我们发现金线偏移中心对透射增强不利.这些结果对铝/金异质聚合物的制作可能有理论指导作用.

All-organic covalent organic frameworks/perylene diimide urea polymer S-scheme photocatalyst for boosted H_(2) generation

Conjugated covalent organic frameworks(COFs)hold great promise in photocatalytic hydrogen evolution owing to their high crystallinity,large surface area,and distinct structure.However,COFs exhibit poor charge separation.Therefore,investigating highly effective COF-based photocatalysts is crucial.For the first time,conjugated COF/perylene diimide urea polymer(PUP)all-organic heterostructure with S-scheme interfacial charge-transfer channels was successfully developed and manufactured via in situ coupling of the two-dimensional triazine-based imine-linked COF(denoted as TATF-COF)with PUP.The optimal photocatalytic hydrogen-evolution rate of 94.5 mmol h^(-1) g^(-1) for TATF-COF/PUP is 3.5 times that of pure TATF-COF and is comparable to or even higher than that of the previously reported COF-based photocatalysts,resulting in an apparent quantum efficiency of up to 19.7%at 420 nm.The improved directional S-scheme charge transfer driven by the tuned built-in electric field and enhanced oxidation and reduction reaction rates of the photogenerated carriers contribute synergistically to the boosted photocatalytic H_(2) evolution.Experiments and theoretical studies reveal plausible H_(2) evolution and spatial S-scheme charge-separation mechanisms under visible-light irradiation.This study provides advanced methods for constructing all-organic S-scheme high-efficiency photocatalysts by the modulation of band structures.

Plasmon-enhanced polymer bulk heterojunction solar cells with solution-processable Ag nanoparticles

We report the plasmon-enhanced polymer bulk-heterojunction solar cells with Ag nanoparticles (AgNPs) obtained via chemical method. Here, the AgNPs films with different particle densities are introduced between the poly (3,4-ethylene dioxythiophene) poly (styrenesulfonate) (PEDOT: PSS) buffer layer and the poly (3-hexythiophene):[6,6]-phenyl-c61 butyric acid methyl ester (P3HT: PCBM) layer. By improving the optical absorption of the active layer owing to the localized surface plasmons, the power conversion efficiency of the solar cells is increased compared with the control device. It is shown that the efficiency of the device increases with the density of AgNPs. For the device employing higher density, the resulted power conversion efficiency is found to increase from 2.89% to 3.38%, enhanced by 16.96%.

High interfacial-energy heterostructure facilitates large-sized lithium nucleation and rapid Li+desolvation process

High interfacial energy Li^(0)-electrolyte interface contributes to larger Li^(0) nucleation embryos and a more stable interface,so the interfacial energy is essential for highly reversible Li^(0) deposition/stripping.Herein,a high interfacial-energy artificial solid electrolyte interphase(SEI)with rich LiF embedded in lithiated poly-2-acrylamido-2-methylpropane sulfonic acid(PAMPS-Li)network is designed to realize favorable Li^(0) nucleation and rapid desolvation of Li+simultaneously.The Li-F bonds in LiF(001)exhibit stronger ion-dipole interactions with Li atoms,offering higher interfacial energies.When the growth surface energy and total interfacial energy of Li^(0) are balanced,the high interfacial energy SEI with abundant LiF can promote the formation of larger Li^(0) nucleation embryos.In addition,the PAMPS-Li with immobilized anions presents weaker interaction with Li^(0) and possesses higher polymer-Li interfacial energy,and its amide and sulfonic acid groups exhibit higher binding energies with Li^(+).Therefore,PAMPS-Li can easily promote the Li+to escape from the solvent sheath and weaken the desolvation energy barrier.The highly reversible Li^(0) deposition behavior with restricted side reactions is achieved based on the synergistic modification of high interfacial energy SEI with heterostructure.Most importantly,lifespan of multi-layered Li^(0) pouch cell(330 Wh kg-1)with a low N/P ratio(1.67)is over 100 cycles,verifying its potential practical application.

Surface plasmonic effect and scattering effect of Au nanorods on the performance of polymer bulk heterojunction solar cells

The surface plasmonic effect and scattering effect of gold nanorods(AuNRs) on the performance of bulk heterojunction photovoltaic devices based on the blend of polythiophene and fullerene are investigated.AuNRs enhance the excitation since the plasmonic effect increases the electric field,mainly in the area near the interface between the active layer and AuNRs.The results show that the incident photo-to-electron conversion efficiency(IPCE) obviously increases for the device with a layer of gold nanorods,resulting from the plasmonic effect of AuNRs in the range of 500-670 nm and the scattering effect in the range of 370-410 nm.The power conversion efficiency(PCE) is increased by 7.6% due to the near field effect of the localized surface plasmons(LSP) of AuNRs and the scattering effect.The short circuit current density is also increased by 9.1% owing to the introduction of AuNRs.However,AuNRs can cause a little deterioration in open circuit voltage.