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Metal nanoparticles associated with local surface plasmon (LSP) resonance, i.e. highly confined electric field and large scattering cross-sections (σ), have been widely used to enhance the light-harvesting of solar cells toward high optoelectronic performance. However, the metal nanoparticles embedded into the solar cells suffer from parasitic ohmic loss that subsequently causes the local temperature to rise, which, in turn, reduces the photoelectric conversion efficiency and stability of solar cells. Previous studies on plasmon-enhanced solar cells have rarely considered the negative effects of metal nanoparticles' ohmic losses and temperature rise on solar cell performance optimization. Therefore, it is of great interest to alleviate the ohmic loss and temperature rise that are critical for high-performance solar cells. Herein, we propose a model to comprehensively study and optimize the performance of plasmon-enhanced perovskite solar cells (PSCs) from simultaneous optical-electrical-thermal aspects. First, the optical simulation results indicated that the geometric tuning of metal nanoparticles can make full use of the plasmonic effect and significantly improve PSCs' light absorption. The analysis showed that the embedded nanoparticles with optimal geometry in PSC devices can significantly increase the optical absorption by 17% (41%) compared to non-optimal nanostructures (devices without nanoparticles). Then, we explored the influence of the temperature-dependent carrier mobility on PSC performance from the coupled electrical and thermal studies. Our results indicated that the optimization of the geometrical parameters of metal nanoparticles can minimize energy dissipation, thereby redusing the heat loss and then lowering the local cell temperature. Interestingly, PSCs' electrical properties such as carrier transportation significantly improved. Consequently, the PSC performance improved with increment in the short-circuit current by 23% and the power conversion efficiency by 38%. [ABSTRACT FROM AUTHOR]

This paper reports the fabrication of a highly sensitive and reusable substrate for surface-enhanced Raman scattering (SERS) analysis. Core–shell metal–organic framework (MOF; HKUST-1)@Ag nanoparticles (NPs) are prepared on a screen-printed carbon electrode (SPCE) via in situ electrodeposition. The morphology and Ag coverage of core–shell structures can be easily controlled by electrodeposition potential and time without substrate motion. The HKUST-1(Cu)@Ag composites combine abundant SERS “hot spots” among the high-density Ag NPs and the excellent adsorption performance of the MOF, resulting in effective pre-concentration of analytes in close proximity to these “hot spots” and enhancement of SERS sensitivity. The optimized polyhedral HKUST-1@Ag structures exhibit high SERS activity for detecting 4-aminothiophenol at a concentration as low as 5 × 10−10 M. More importantly, the polyhedral HKUST-1@Ag composites provide high sensitivity for detection of polycyclic aromatic hydrocarbons (PAHs) while preserving the cyclability and selectivity required for reliable quantitative analysis. The method is effective over a wide range of PAH concentrations (0.5 nM to 0.5 M), with detection limits as low as hundreds of pM. This study offers a new method to tailor the structure of MOF-based SERS substrates for on-site screening or point-of-care applications. [ABSTRACT FROM AUTHOR]

The dielectric/ultra-thin metal/dielectric structure has been widely used for semi-transparent electrodes in organic solar cells (OSCs) due to its potential replacement of the transparent conductive oxide indium tin oxide. Here, we introduce the dual light trapping structures, i.e. the nanopatterned MoO3/Ag/MoO3 (MAM) as the anode and a short-pitched metallic grating as the cathode, to cooperatively improve the OSC performance. The optical and electrical properties of the OSCs have been investigated via solving the coupled Maxwell and semiconductor equations by the finite-difference method. The results indicate that the optical light absorption of the active layer and the electrical carrier collection have been significantly enhanced after the adoption of the proposed dual light trapping structures. We have shown that the optical and electrical improvements are attributed to the synergetic effects of surface plasmon resonance of the grating patterned cathode and scattering effect of the nanopatterned MAM anode. Our results have further revealed that the short-pitched metal grating can induce considerable field confinement due to the mode coupling and hybridization of the surface plasmons in-between the adjacent short-distance metal strips. With the optimized structural parameters of the dual light trapping structure, the power conversion efficiency (PCE) of the OSCs has been substantially enhanced by 39% in comparison with a flat cell. Besides the efficiency improvement, the OSCs with the proposed dual light harvesting structures reveal an alleviated angular dependence of electrical properties as the light is beyond the normal incident angle. Our results contribute to the further development of ITO-free OSCs and are promising for semi-transparent optoelectronics. [ABSTRACT FROM AUTHOR]

Recently, nanoparticle–film coupling systems in which metal nanoparticles (supported localized surface plasmons, LSPs) are separated from a flat metal film (supported surface plasmon polaritons, SPPs) by a spacer have been widely reported due to its strong local enhancement field. However, there is are limited studies, which employ the design of combing metal grating into the nanoparticle–film gap system. Here, we propose and fabricate a novel double-resonance SERS system by strategically assembling Au NPs separated by a MoO3 nanospacer from an Ag grating film. The Ag grating with clear SPP effect is used for the first time in a double-resonance system, and the monolayer Au NPs array is well assembled onto the top of the Ag grating with a compact and uniform distribution (inter-particles gap of about 5 nm). As a result, we experimentally and theoretically demonstrate a significant near-field enhancement. The very strong near-field produced in the proposed SERS substrates is due to multiple couplings, including the Au NPs–Ag grating film coupling and Au NPs–Au NPs coupling. In addition, the as-proposed SERS substrates show good reproducibility of SERS, which have potential applications in plasmonic sensing and analytical science. [ABSTRACT FROM AUTHOR]