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

Plasmon resonances in metal nanostructures have been extensively harnessed for light trapping in mesoporous solar cells (MSCs), including dye-sensitized solar cells (DSSCs) and recently in perovskite solar cells (PSCs). By altering the geometry, dimension, and composition of metal nanostructures, their optical characteristics can be tuned to either overlap with the sensitizer absorption and enhance light harvesting, or absorb light at a wavelength complementary to the sensitizer enabling broadband solar light capture in MSCs. In this comprehensive review, we discuss the mechanisms of plasmonic enhancement in MSCs including far-field coupling of scattered light, near-field coupling of localized electromagnetic fields, hot electron transfer, and plasmon resonant energy transfer. We then summarize the progress in plasmon enhanced DSSCs in the past decade and decouple the impact of metal nanostructure shape, size, composition, and surface coatings on the overall efficiency. Further, we also discuss the recent advances in plasmon-enhanced perovskite solar cells. Distinct from other published reviews, we discuss the significance of femtosecond spectroscopies to probe the fundamental underpinnings of plasmon enhanced phenomena and understand the mechanisms that give rise to energy transfer between metal nanoparticles and solar materials. The review concludes with a discussion on the challenges in plasmonic device fabrication, and the promise of low-loss semiconductor nanocrystals for plasmonic enhancement in MSCs that facilitate light capture in the infrared.

/pdf/light-trapping-in-mesoporous-solar-cells-with-plasmonic-4ngdgoyabs.pdf

Light trapping in mesoporous solar cells with plasmonic nanostructures

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

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.

In this paper low cost and earth abundant Al nanoparticles are simulated and compared with noble metal nanoparticles Ag and Au for plasmonic light trapping in Si wafer solar cells. It has been found tailored Al nanoparticles enable broadband light trapping leading to a 28.7% photon absorption enhancement in Si wafers, which is much larger than that induced by Ag or Au. Once combined with the SiNx anti-reflection coating, Al nanoparticles can produce a 42.5% enhancement, which is 4.3% higher than the standard SiNx due to the increased absorption in both the blue and near-infrared regions.

https://researchbank.swinburne.edu.au/file/67e28fce-c165-498f-81d1-102b902796e2/1/PDF (Published version).pdf

Low cost and high performance Al nanoparticles for broadband light trapping in Si wafer solar cells

Nanoplasmonics recently has emerged as a new frontier of photovoltaic research. Noble metal nanostructures that can concentrate and guide light have demonstrated great capability for dramatically improving the energy conversion effi- ciency of both laboratory and industrial solar cells, providing an innovative pathway potentially transforming the solar industry. However, to make the nanoplasmonic technology fully appreciated by the solar industry, key challenges need to be addressed; including the detrimental absorption of metals, broadband light trapping mechanisms, cost of plasmonic nanomaterials, simple and inexpensive fabrication and integration methods of the plasmonic nanostructures, which are scalable for full size manufacture. This article reviews the recent progress of plasmonic solar cells including the fundamental mechanisms, material fabrication, theoretical modelling and emerging directions with a distinct emphasis on solutions tackling the above-mentioned challenges for industrial relevant applications.

https://www.degruyter.com/downloadpdf/j/nanoph.2012.1.issue-3-4/nanoph-2012-0180/nanoph-2012-0180.xml

Nanoplasmonics: a frontier of photovoltaic solar cells

Significant photocurrent enhancement of 0.4 mA/cm2 has been achieved for industrial textured multicrystalline silicon solar cells, due to the light trapping provided by aluminium nanoparticle enhanced antireflection coating. Aluminium nanoparticles support surface plasmon resonances, which can effectively scatter the light into the solar cells. By blue shifting the detrimental Fano resonances away from the important silicon absorption spectrum, aluminium nanoparticles can provide a broadband light absorption enhancement without a reduction at the short wavelengths. Combining the discovery with 75 nm silicon nitride antireflection coating, which can significantly enhance the absorption at the peak solar spectrum, we have achieved the strong broadband light absorption enhancement.

https://researchbank.swinburne.edu.au/file/0f00d9e1-1f9c-4536-81b8-af9e7d11c084/1/PDF (Published version).pdf

Improved multicrystalline Si solar cells by light trapping from Al nanoparticle enhanced antireflection coating

Multicrystalline silicon solar cells play an increasingly important role in the world photovoltaic market Boosting the comparatively low energy conversion efficiency of multicrystalline silicon solar cells is of great academic and industrial significance In this paper, Au nanoparticles of an optimized size, synthesized by the iterative seeding method, were integrated onto industrially available surface-textured multicrystalline silicon solar cells via a dip coating method Enhanced performance of the light absorption, the external quantum efficiency and the energy conversion efficiency were consistently demonstrated, resulting from the light scattering by the sized-tailored Au nanoparticles placed on the front surface of the solar cells, particularly in the spectral range from 800 to 1200 nm, an enhancement of the external quantum efficiency by more than 11% near λ = 1150 nm and the short-circuit current by 093% were both observed As a result, an increase in the energy conversion efficiency up to 197% under the standard testing conditions (25°C, global air mass 15 spectrum, 1000 Wm−2) was achieved This study opens new perspectives for plasmonic nanoparticle applications for photon management in multicrystalline silicon solar cells

https://researchbank.swinburne.edu.au/file/26ddf360-2859-4342-aa65-fb0f8b070bf4/1/PDF (Published version).pdf

Zhengrong Shi

Papers

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

Low cost and high performance Al nanoparticles for broadband light trapping in Si wafer solar cells

Nanoplasmonics: a frontier of photovoltaic solar cells

Improved multicrystalline Si solar cells by light trapping from Al nanoparticle enhanced antireflection coating

Efficiency enhancement of screen-printed multicrystalline silicon solar cells by integrating gold nanoparticles via a dip coating process