Plasmon Enhanced Direct Bandgap Emissions in Cu7S4@Au2S@Au Nanorings

Nanostructured copper sulfides, promising earth‐abundant p‐type semiconductors, have found applications in a wide range of fields due to their versatility, tunable low bandgap, and environmental sustainability. The synthesis of hexagonal Cu₇S₄@Au₂S@Au nanorings exhibiting plasmon enhanced emissions at the direct bandgap is reported. The synthesized Cu₇S₄@Au₂S@Au nanorings show greatly enhanced absorption and emission by local plasmons compared to pure copper sulfide nanoparticles.     

Low energy electron induced characteristic losses in the Fe73.6Cu1Nb2.4Si15.8B7.2 (FINEMET) alloy surface

Electron Energy Loss Spectroscopy has been employed for investigation of the electronic states of amorphous and crystalline Fe_73.6Cu₁Nb_2.4Si_15.8B_7.2 (FINEMET) alloy surface and alloy components. Electron energy losses have been measured for primary electron beam energies E₀ from 150 to 650 eV. The characteristic energy loss spectra were composed of main peaks which we have interpreted due to surface and bulk plasmons, a combination of surface and bulk losses, high harmonics of plasma losses, inter-band transitions and ionization of core levels. The measured energies for the plasmon excitations were found not to agree with calculated values according to the classical theory for the collective oscillations in solids. Changes in the intensity lines of the surface and bulk plasmons were observed for all specimens depending on primary electron energy E₀. The present results are compared with characteristic energy loss data reported in the literature.     

Local Field Enhancement Tuning of Horseshoe-Shaped Nanoparticles

We proposed a horseshoe-shaped nano-structure formed by etching a gap on a ring structure. By numerical simulations, it was found that the local field of the structure was significantly enhanced compared with that of the traditional ring structure. Furthermore, an additional resonant peak appeared corresponding to the electric field coupling in the gap, and this resonant wavelength was able to be tuned significantly by the particle size, gap size, and gap position. Such properties make the structure promising in biomedical and sensing applications.     

Formation of a Quasi‐Free‐Standing Single Layer of Graphene and Hexagonal Boron Nitride on Pt(111) by a Single Molecular Precursor

It is shown that on Pt(111) it is possible to prepare hexagonal boron nitride (h‐BN) and graphene (G) in‐plane heterojunctions from a single molecular precursor, by thermal decomposition of dimethylamine borane (DMAB). Photoemission, near‐edge X‐ray absorption spectroscopy, low energy electron microscopy, and temperature programmed desorption measurements indicate that the layer fully covers the Pt(111) surface. Evidence of in‐plane layer continuity and weak interaction with Pt substrate has been established. The findings demonstrate that dehydrogenation and pyrolitic decomposition of DMAB is an efficient and easy method for obtaining a continuous almost freestanding layer mostly made of G, h‐BN with only a low percentage (<3%) of impurities (B and N‐doped G domains or C‐doped h‐BN or boron carbonitride, BCN at the boundaries) in the same 2D sheet on a metal substrate, such as Pt(111), paving the way for the advancement of next‐generation G‐like‐based electronics and novel spintronic devices.     

Broadband Photoresponse Enhancement of a High‐Performance t‐Se Microtube Photodetector by Plasmonic Metallic Nanoparticles

Broadband responsivity enhancement of single Se microtube (Se‐MT) photodetectors in the UV–visible region is presented in this research. The pristine Se‐MT photodetector demonstrates broadband photoresponse from 300 to 700 nm with peak responsivity of ≈19 mA W^?1 at 610 nm and fast speed (rise time 0.32 ms and fall time 23.02 ms). To further enhance the responsivity of the single Se‐MT photodetector, Au and Pt nanoparticles (NPs) are sputtered on these devices. In contrast to only enhancement of responsivity in UV region by Pt NPs, broadband responsivity enhancement (≈600% to ≈800%) of the Se‐MT photodetector is realized from 300 to 700 nm by tuning the size and density of Au NPs. The broadband responsivity enhancement phenomena are interpreted by both the surface modification and surface plasmon coupling. The experimental results of this work provide an additional opportunity for fabricating high‐performance UV–visible broadband photodetectors.     

等离激元共振增强多晶硅薄膜太阳电池性能研究

采用磁控溅射方法,在多晶硅薄膜太阳电池表面沉积了不同粒径大小的Au纳米粒子,利用粒径大小可调控的Au纳米粒子的局域表面等离激元共振增强效应(LSPR),对入射光中的可见光区域实现“光俘获”;采用UV-vis吸收光谱对LSPR进行了研究,结果表明,LSPR能够有效拓展Au纳米粒子的光谱响应范围(400～800 nm),并且,随着Au纳米粒子粒径的增大,LSPR共振吸收峰呈现出明显“红移”;同时,通过SERS表征,证实LSPR能够有效增强Au纳米粒子周围的局域电磁场强度;最后,多晶硅太阳电池的J-V特性曲线表明,当Au纳米粒子溅射时间为50 s时,多晶硅太阳电池光电转换效率(η)最高为14.8％,比未修饰Au纳米粒子的电池η提高了42.3％.     

Enhanced Structural Stability and Performance Durability of Bulk Heterojunction Photovoltaic Devices Incorporating Metallic Nanoparticles

Despite the progress on organic photovoltaic (OPV) performance, the photoactive layer degradation during prolonged solar illumination is still a major obstacle. In this work, an approach to mitigate the degradation pathway related to structural/morphological changes of the photoactive layer occurring upon continuous illumination in air is presented. It is shown, for the first time, that the incorporation of Ag nanoparticles in poly(3‐hexylthiophene) (P3HT) and [6‐6]‐phenyl‐C61‐butyric acid methyl ester bulk heterojunction (BHJ) leads to improved structural and morphological properties of the composite BHJ solar cells and to better photovoltaic (PV) stability after long periods of continuous illumination. This is evidenced by an original approach based on joint in‐situ time‐resolved X‐ray and atomic force microscopy monitoring. Besides the structural stability improvement and reduced photodegradation rate, it is shown that the composite blends exhibit superior PV performance compared to the pristine BHJs. It can be postulated that the incorporation of metallic nanoparticles in the BHJ leads to a dual enhancement, a plasmon absorption mediated effect, causing improved initial cell efficiency, and a structural stability effect giving rise to reduced degradation rate upon prolonged illumination. The results are in favor of the exploitation of polymer–nanoparticle composites as a promising approach to mitigate the aging effects in OPVs.     

Polymer Brush Guided Formation of Conformal,Plasmonic Nanoparticle‐Based Electrodes for Microwire Solar Cells

This report explores the use of sacrificial thin polymer films prepared by surface‐initiated polymerization as a template for the fabrication of highly conformal metal nanoparticle solar cell electrodes. As a first proof‐of‐principle, the use of this method is demonstrated to prepare top electrodes on planar and microwire‐based silicon solar cell devices. These metal nanoparticle films are dual functional in that they not only mediate charge transport, but also enhance light capture due to the plasmonic scattering properties of the nanoparticles. Solar cells with a conformal silver nanoparticle‐based electrode layer show short circuit currents that are 46% higher as compared to those exhibit by devices coated with standard indium tin oxide as the electrode. It is anticipated that this methodology will contribute to novel electrode concepts in the next generation solar cells.     

Effect of coupling between excitons and gold nanoparticle surface plasmons on emission behavior of phosphorescent organic light-emitting diodes

Enhanced efficiency and reduced efficiency roll-off in phosphorescent organic light-emitting diodes (PhOLEDs) are realized by interposing a solution-processed gold nanoparticle (GNP)-based interlayer between the anode and the hole-injection layer. Transient photoluminescence measurements elucidate that a reduced lifetime of the triplet excitons was observed for samples having a GNP-interlayer as compared to a control sample without the GNP-interlayer. The decrease in the triplet exciton lifetime, caused by the coupling between the triplet excitons and the localized surface plasmons (LSPs) excited by the GNPs, enables reducing the triplet–triplet and triplet–polaron annihilation processes, thereby a reduced efficiency roll-off in PhOLEDs. The presence of a GNP-interlayer also acts as an optical out-coupling layer contributing to the efficiency enhancement and was demonstrated by the theoretical simulation.