Health, infrastructure, and environmental monitoring as well as networking and defense technologies are only some of the potential areas of application of micro-/nanosystems (MNSs). It is highly desirable that these MNSs operate without an external electricity source and instead draw the energy they require from the environment in which they are used. This Review covers various approaches for energy harvesting to meet the future demand for self-powered MNSs.

Nanotechnology-Enabled Energy Harvesting for Self-Powered Micro-/Nanosystems

Over the past few decades, metal nanoparticles less than 100 nm in diameter have made a substantial impact across diverse biomedical applications, such as diagnostic and medical devices, for personalized healthcare practice. In particular, silver nanoparticles (AgNPs) have great potential in a broad range of applications as antimicrobial agents, biomedical device coatings, drug-delivery carriers, imaging probes, and diagnostic and optoelectronic platforms, since they have discrete physical and optical properties and biochemical functionality tailored by diverse size- and shape-controlled AgNPs. In this review, we aimed to present major routes of synthesis of AgNPs, including physical, chemical, and biological synthesis processes, along with discrete physiochemical characteristics of AgNPs. We also discuss the underlying intricate molecular mechanisms behind their plasmonic properties on mono/bimetallic structures, potential cellular/microbial cytotoxicity, and optoelectronic property. Lastly, we conclude this review with a summary of current applications of AgNPs in nanoscience and nanomedicine and discuss their future perspectives in these areas.

https://www.mdpi.com/1422-0067/20/4/865/pdf

Silver Nanoparticles: Synthesis and Application for Nanomedicine

Plasmonic metal nanoparticles are of great interest for light trapping in thin-film silicon solar cells. In this Letter, we demonstrate experimentally that a back reflector with plasmonic Ag nanoparticles can provide light-trapping performance comparable to state-of-the-art random textures in n-i-p amorphous silicon solar cells. This conclusion is based on the comparison to high performance n-i-p solar cell and state-of-the-art efficiency p-i-n solar cells deposited on the Asahi VU-type glass. With the plasmonic back reflector a gain of 2 mA/cm2 in short-circuit current density was obtained without any deterioration of open circuit voltage or fill factor compared to the solar cell on a flat back reflector. The excellent light trapping is a result of strong light scattering and low parasitic absorption of self-assembled Ag nanoparticles embedded in the back reflector. The plasmonic back reflector provides a high degree of light trapping with a haze in reflection greater than 80% throughout the wavelength r...

Plasmonic Light Trapping in Thin-film Silicon Solar Cells with Improved Self-Assembled Silver Nanoparticles

It is been widely reported that plasmonic effects in metallic nanomaterials can enhance light trapping in organix solar cells (OSCs). However, typical nanoparticles (NP) of high quality (i.e., mono-dispersive) only possess a single resonant absorption peak, which inevitably limits the power conversion efficiency (PCE) enhancement to a narrow spectral range. Broadband plasmonic absorption is obviously highly desirable. In this paper, a combination of Ag nanomaterials of different shapes, including nanoparticles and nanoprisms, is proposed for this purpose. The nanomaterials are synthesized using a simple wet chemical method. Theoretical and experimental studies show that the origin of the observed PCE enhancement is the simultaneous excitation of many plasmonic low- and high-order resonances modes, which are material-, shape-, size-, and polarization-dependent. Particularly for the Ag nanoprisms studied here, the high-order resonances result in higher contribution than low-order resonances to the absorption enhancement of OSCs through an improved overlap with the active material absorption spectrum. With the incorporation of the mixed nanomaterials into the active layer, a wide-band absorption improvement is demonstrated and the short-circuit photocurrent density (Jsc) improves by 17.91%. Finally, PCE is enhanced by 19.44% as compared to pre-optimized control OSCs. These results suggest a new approach to achieve higher overall enhancement through improving broadband absorption.

Efficiency Enhancement of Organic Solar Cells by Using Shape‐Dependent Broadband Plasmonic Absorption in Metallic Nanoparticles

Plasmonic materials for energy: From physics to applications

Recently plasmonic effects have gained tremendous interest in solar cell research because they are deemed to be able to dramatically boost the efficiency of thin-film solar cells. However, despite of the intensive efforts, the desired broadband enhancement, which is critical for real device performance improvement, has yet been achieved with simple fabrication and integration methods appreciated by the solar industry. We propose in this paper a novel idea of using nucleated silver nanoparticles to effectively scatter light in a broadband wavelength range to realize pronounced absorption enhancement in the silicon absorbing layer. Since it does not require critical patterning, experimentally these tailored nanoparticles were achieved by the simple, low-cost and upscalable wet chemical synthesis method and integrated before the back contact layer of the amorphous silicon thin-film solar cells. The solar cells incorporated with 200 nm nucleated silver nanoparticles at 10% coverage density clearly demonstrate a broadband absorption enhancement and significant superior performance including a 14.3% enhancement in the short-circuit photocurrent density and a 23% enhancement in the energy conversion efficiency, compared with the randomly textured reference cells without nanoparticles. Among the measured plasmonic solar cells the highest efficiency achieved was 8.1%. The significant enhancement is mainly attributed to the broadband light scattering arising from the integration of the tailored nucleated silver nanoparticles.

Broadband enhancement in thin-film amorphous silicon solar cells enabled by nucleated silver nanoparticles.

The concept of using plasmonic nanostructures to manage light in solar cells has offered an unprecedented potential for dramatically increased solar energy conversion efficiency that breaks the previously predicated efficiency limit. In the past decade, intensive research efforts have been focused on this field. However, nanoplasmonic solar cells still remained in the laboratory level. To facilitate the transformation of the nanoplasmonic solar cell concept to a viable high-efficiency technology solution for the solar industry, it is essential to address key fundamental as well as practical challenges including the detrimental absorption of metallic nanostructures, narrow-band absorption enhancement in the active layer, the high cost and scarcity of noble metals, and the expensive and complicated plasmonic nanomaterial fabrication and integration methods. In this paper, after a brief review of our main results in nanoplasmonic solar cells, we present our strategies for using innovative photonic methods to overcome these challenges and demonstrate a large-area (173  cm2) broadband plasmonic thin-film solar minimodule with an efficiency of 9.5% resulting from the enhanced plasmonic light scattering enabled by silver lumpy nanoparticles with an ultralow nanoparticle coverage density of 5%.

https://researchbank.swinburne.edu.au/file/a3c10f74-969d-41b1-be28-45ff2cac66f6/1/PDF (Published version).pdf

Concept to devices: from plasmonic light trapping to upscaled plasmonic solar modules [Invited]

Strong scattering intensities in a broadband wavelength range from metallic nanoparticles are essential for diverse photonics applications Conventional ways of controlling particle scattering are via the control of the size, shape and embedding dielectric environment In this paper we demonstrate that tailoring the particle surface roughness is another effective way of controlling particle scattering Roughly surfaced lumpy silver nanoparticles, which have anisotropic surface topography, are realized by a controlled shape- and size-selective wet chemical method Through the systematic comparison with the smoothly surfaced nanoparticles of the same size and size distribution, we verify both experimentally and theoretically that the lumpy nanoparticles produce large-angle broadband plasmonic scattering due to their unique surface anisotropic structure

http://researchbank.swinburne.edu.au/file/16077629-1e76-47a4-8989-a8ae371c4c54/1/PDF (Published version).pdf

Strong broadband scattering of anisotropic plasmonic nanoparticles synthesized by controllable growth: effects of lumpy morphology

The invention provides a back local contact structure of a solar battery, a manufacture method of the structure, the corresponding solar battery and a manufacture method of the solar battery. Problems of spinning or spraying boron polymers is not beneficial to process integration and low in utilization efficiency, has poisoning dangers and the like during the manufacture of back local structures exist in the prior art. The manufacture method of the back local contact structure of the solar battery and the manufacture method of the corresponding solar battery comprise cleaning a silicon wafer, subjecting the front side to diffusion to manufacture a PN joint, and etching the edges; depositing a passivation layer on the back of the silicon wafer and an amorphous dielectric doped layer of a same doped type with the silicon wafer on the passivation layer; forming a local heavily doped region in a local region on the back of the silicon wafer, and forming an opening at a corresponding position of the amorphous dielectric doped layer and the passivation layer; and forming a back electrode electrically connected with the local heavily doped region through the opening on the back of the silicon wafer. The back local contact structure of the solar battery, the manufacture method of the structure, the corresponding solar battery and the manufacture method of the solar battery can improve the process integration level, the source utilization rate and the operation safety and non-toxicity effectively.

Back local contact structure of solar battery, manufacture method of structure, corresponding solar battery and manufacture method of solar battery

The invention relates to the photovoltaic cell manufacturing field, and more specifically relates to a method for preparing a substrate with gallium-doped zinc oxide texture, a substrate prepared by the same and a silicon thin-film solar cell comprising the substrate. The method for preparing a substrate can help obtain the substrate with gallium-doped zinc oxide texture and relieve silicon thin-film solar cell manufacturers from restrictions from textured tin oxide glass suppliers, thus further reducing production and manufacturing cost. The method can be directly applied to production and manufacture of the silicon thin-film solar cell, and the substrate prepared by the method can replace the existing expensive textured tin oxide glass substrate, and shows better properties.

Yongqian Wang

Papers

Broadband enhancement in thin-film amorphous silicon solar cells enabled by nucleated silver nanoparticles.

Concept to devices: from plasmonic light trapping to upscaled plasmonic solar modules [Invited]

Strong broadband scattering of anisotropic plasmonic nanoparticles synthesized by controllable growth: effects of lumpy morphology

Back local contact structure of solar battery, manufacture method of structure, corresponding solar battery and manufacture method of solar battery

Method for preparing substrate with gallium-doped zinc oxide texture and substrate prepared by the same