Localized surface plasmon resonance (LSPR) of doped Si nanocrystals (NCs) is critical to the development of Si-based plasmonics. We now experimentally show that LSPR can be obtained from both B- and ...P-doped Si NCs in the mid-infrared region. Both experiments and calculations demonstrate that the Drude model can be used to describe the LSPR of Si NCs if the dielectric screening and carrier effective mass of Si NCs are considered. When the doping levels of B and P are similar, the LSPR energy of B-doped Si NCs is higher than that of P-doped Si NCs because B is more efficiently activated to produce free carriers than P in Si NCs. We find that the plasmonic coupling between Si NCs is effectively blocked by oxide at the NC surface. The LSPR quality factors of B- and P-doped Si NCs approach those of traditional noble metal NCs. We demonstrate that LSPR is an effective means to gain physical insights on the electronic properties of doped Si NCs. The current work on the model semiconductor NCs, i.e., Si NCs has important implication for the physical understanding and practical use of semiconductor NC plasmonics.
Diamond cubic silicon is widely used for electronic applications, integrated circuits, and photovoltaics, due to its high abundance, nontoxicity, and outstanding physicochemical properties. However, ...it is a semiconductor with an indirect band gap, depriving its further development. Fortunately, other polymorphs of silicon have been discovered successfully, and new functional allotropes are continuing to emerge, some of which are even stable in ambient conditions and could form the basis for the next revolution in electronics, stored energy, and optoelectronics. Such structures can lead to some excellent features, including a wide range of direct or quasi-direct band gaps allowed efficient for photoelectric conversion (examples include Si-III and Si-IV), as well as a smaller volume expansion as lithium-battery anode material (such as Si24, Si46, and Si136). This review aims to give a detailed overview of these exciting new properties and routes for the synthesis of novel Si allotropes. Lastly, the key problems and the developmental trends are put forward at the end of this article.
Three-dimensional (3D) thermal reduced graphene network (TRGN) deposition on Ni foam without any conductive agents and polymer binders was successfully synthesized by dipping Ni foam into graphene ...oxide (GO) suspension and subsequent thermal reduction process. The direct and close contact between thermal reduced graphene and Ni foam is beneficial to the enhanced conductivity of the electrode, as well as the improvement of ion diffusion/transport into the electrode. Additionally, low-temperature reduction of GO possesses a large amount of stable oxygen-containing groups that can provide high pseudocapacitance. As a result, the TRGN electrode delivers a high specific capacitance of 442.8Fg−1 at 2mVs−1 in 6molL−1 KOH. Moreover, symmetric supercapacitor based on TRGN exhibits a maximum energy density of 30.4Whkg−1 based on the total mass of the two electrodes in 1molL−1 Na2SO4 electrolyte, as well as excellent cycling stability with 118% of its initial capacitance after 5000 cycles.
Among all types of solar cells, multicrystalline silicon (Si) solar cells are the most widely produced. The enhancement of the efficiency of multicrystalline Si solar cells may help broaden the ...deployment of solar cells worldwide. Here we show that the efficiency of state-of-the-art commercially produced multicrystalline Si solar cells can be enhanced by a simple inkjet printing of Si-quantum-dot (Si-QD) ink at the solar cell surface. It is found that the efficiency enhancement results from both the down-shifting of Si QDs and the antireflection of porous Si-QD films at the solar cell surface. The current results demonstrate that Si-based nanotechnology can facilitate the continuous development of traditional Si solar cells.
Noble-metal nanocrystals with well-defined and controllable morphologies are of great importance to applications in catalysis, plasmonics, and surface-enhanced spectroscopy. Many synthetic approaches ...have been demonstrated for controlling the growth habit and thus morphology of metal nanocrystals, but most of them are based on a thermodynamic approach, including the use of a capping agent. While thermodynamic control has shown its power in generating nanocrystals with a myriad of different morphologies, it is ultimately limited by the obligation to minimize the surface energy of a system. As a result, it is impractical to use thermodynamic control to generate nanocrystals having high-energy facets and/or a negative curvature. Using rhodium as an example, here we demonstrate a general method based on kinetic control with a syringe pump that can be potentially extended to other noble metals and even other solid materials. For the first time, we were able to produce concave nanocubes with a large fraction of {110} facets and octapods with a cubic symmetry in high yields by simply controlling the injection rate at which the precursor was added into the reaction solution. The concave nanocubes with {110} facets and a unique cavity structure on the surface are important for a variety of applications.
Designing new materials and structure to sustain the corrosion during operation requires better understanding on the corrosion dynamics. Observation on how the corrosion proceeds in atomic scale is ...thus critical. Here, using a liquid cell, we studied the real-time corrosion process of palladium@platinum (Pd@Pt) core-shell nanocubes via transmission electron microscopy (TEM). The results revealed that multiple etching pathways operatively contribute to the morphology evolution during corrosion, including galvanic etching on non-defected sites with slow kinetics and halogen-induced etching at defected sites at faster rates. Corners are the preferential corrosion sites; both etching pathways are mutually restricted during corrosion. Those insights on the interaction of nanostructures with reactive liquid environments can help better engineer the surface structure to improve the stability of electrocatalysts as well as design a new porous structure that may provide more active sites for catalysis.
Abstract
Treating hazardous waste Ni from the electroplating industry is mandated world-wide, is exceptionally expensive, and carries a very high CO
2
footprint. Rather than regarding Ni as a ...disposable waste, the chemicals and petrochemicals industries could instead consider it a huge resource. In the work described herein, we present a strategy for upcycling waste Ni from electroplating wastewater into a photothermal catalyst for converting CO
2
to CO. Specifically, magnetic nanoparticles encapsulated in amine functionalized porous SiO
2
, is demonstrated to efficiently scavenge Ni from electroplating wastewater for utilization in photothermal CO
2
catalysis. The core-shell catalyst architecture produces CO at a rate of 1.9 mol·g
Ni
−1
·h
−1
(44.1 mmol·g
cat
−1
·h
−1
), a selectivity close to 100%, and notable long-term stability. This strategy of upcycling metal waste into functional, catalytic materials offers a multi-pronged approach for clean and renewable energy technologies.
In this paper, we use the spin-on-dopant technique for phosphorus doping to improve the photoelectric properties of soft-chemical-prepared silicon nanosheets. It was found that the luminescence ...intensity and luminescence lifetime of the doped samples was approximately 4 fold that of the undoped samples, due to passivation of the surface defects by phosphorus doping. Meanwhile, phosphorus doping combined with high-temperature heat treatment can reduce the resistivity of multilayer silicon nanosheets by 6 fold compared with that of as-prepared samples. In conclusion, our work brings soft-chemical-prepared silicon nanosheets one step closer to practical application in the field of optoelectronics.
A simple microemulsion-based method has been developed to synthesize ZnCo2(C2O4)3 nanowires that can be transformed to porous ZnCo2O4 nanowires under annealing conditions. The morphology of porous ...ZnCo2O4 nanowires can be tuned by the initial ZnCo2(C2O4)3 nanowires and the annealing temperatures. The as-synthesized porous ZnCo2O4 nanowires have been applied as anode materials of Li-ion batteries, which show superior capacity and cycling performance. The porous one-dimensional (1D) nanostructures and large surface area are responsible for the superior performance. Moreover, it is indicated that porous ZnCo2O4 nanowires synthesized at low annealing temperature (500 °C) show larger capacity and better cycling performance than that prepared at high annealing temperature (700 °C), because of their higher porosity and larger surface area.
We have demonstrated the seed-assisted cast quasi-single crystalline (QSC) silicon technique to achieve high efficiency solar cells with low cost. Compared to multicrystalline (mc) silicon, the QSC ...silicon has better material properties, having higher minority carrier lifetime and fewer grain boundaries and dislocations. Furthermore, the 〈100〉 oriented QSC silicon can achieve a lower surface reflectance using alkaline texturing. Based on these two factors, the efficiency of the QSC silicon solar cells with the industrial size has been improved by up to 1% absolutely from the mc-Si counterparts. Compared to the Czochralski (CZ) silicon solar cells, the QSC cells have slightly lower efficiency but high productivity and negligible light-induced degradation. These results suggest a great potential of the QSC silicon applied in photovoltaic industry as the next generation substrate. To make the QSC silicon more competitive in industry, further efforts should be focused on the recycling of seed crystals, the coverage of mono-region and the control of structural defects.
► We fabricated the quasi-single crystalline (QSC) silicon by seed-assisted process. ► QSC silicon has better material properties. ► 〈100〉 QSC silicon can achieve lower surface reflectance by alkaline texturing. ► QSC solar cell has higher efficiency that the multicrystalline counterpart. ► QSC silicon solar cells have negligible light-induced degradation under sunlight.
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