Design of Nanostructured Solar Cells Using Coupled Optical and Electrical Modeling Michael G. Deceglie † , Vivian E. Ferry ‡ , A. Paul Alivisatos ‡ , and Harry A. Atwater* ,† Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, Pasadena, California 91125, United States Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States Abstract: Nanostructured light trapping has emerged as a promising route toward improved efficiency in solar cells. We use coupled optical and electrical modeling to guide optimization of such nanostructures. We study thin-film n-i-p a-Si:H devices and demonstrate that nanostructures can be tailored to minimize absorption in the doped a-Si:H, improving carrier collection efficiency. This suggests a method for device optimization in which optical design not only maximizes absorption, but also ensures resulting carriers are efficiently collected. Keywords: Thin film solar cells, plasmon, nanophotonic, light trapping, simulation, device physics, silicon, photovoltaics In order to maximize solar cell efficiency, it is necessary to optimize both the electrical device physics and the optical absorption of the device. Typically, these two problems are treated separately,

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Design of Nanostructured Solar Cells Using Coupled Optical and Electrical Modeling - eScholarship

Localized surface plasmon resonances (LSPRs) associated with metallic nanostructures offer unique possibilities for light concentration beyond the diffraction limit, which can lead to strong field confinement and enhancement in deep subwavelength regions. In recent years, many transformative plasmonic applications have emerged, taking advantage of the spectral and spatial tunability of LSPRs enabled by near-field coupling between constituent metallic nanostructures in a variety of plasmonic metastructures (dimers, metamolecules, metasurfaces, metamaterials, etc.). For example, the “hot spot” formed at the interstitial site (gap) between two coupled metallic nanostructures in a plasmonic dimer can be spectrally tuned via the gap size. Capitalizing on these capabilities, there have been significant advances in plasmon enhanced or enabled applications in light-based science and technology, including ultrahigh-sensitivity spectroscopies, light energy harvesting, photocatalysis, biomedical imaging and theranostics, optical sensing, nonlinear optics, ultrahigh-density data storage, as well as plasmonic metamaterials and metasurfaces exhibiting unusual linear and nonlinear optical properties. In this review, we present two complementary approaches for fabricating plasmonic metastructures. We discuss how meta-atoms can be assembled into unique plasmonic metastructures using a variety of nanomanipulation methods based on single- or multiple-probes in an atomic force microscope (AFM) or a scanning electron microscope (SEM), optical tweezers, and focused electron-beam nanomanipulation. We also provide a few examples of nanoparticle metamolecules with designed properties realized in such well-controlled plasmonic metastructures. For the spatial controllability on the mesoscopic and macroscopic scales, we show that controlled self-assembly is the method of choice to realize scalable two-dimensional, and three-dimensional plasmonic metastructures. In the section of applications, we discuss some key examples of plasmonic applications based on individual hot spots or ensembles of hot spots with high uniformity and improved controllability.

Nanomanipulation and controlled self-assembly of metal nanoparticles and nanocrystals for plasmonics

A moth-eye nanostructured mp-TiO2 film using conventional lithography, nano-imprinting and polydimethyl-siloxane (PDMS) stamping methods is demonstrated for the first time. Power conversion efficiency of the moth-eye patterned perovskite solar cell is improved by ≈11%, which mainly results from increasing light harvesting efficiency by structural optical property.

Moth-Eye TiO2 Layer for Improving Light Harvesting Efficiency in Perovskite Solar Cells.

Multifurcated assemblies composed of charged nanoparticles (NPs) are fabricated by using spark discharge and manipulating the electric field. The multifurcated structure of the assembly of NPs and spontaneous interconnections between the near structures are described. The gas sensor with the tetrafurcated-NP-assembled structure demonstrates ≈200% enhanced response to 100 ppm CO at 300 °C.

Multifurcation Assembly of Charged Aerosols and Its Application to 3D Structured Gas Sensors

Boosting ultrathin aSi-H solar cells absorption through a nanoparticle cross-packed metasurface

We report three-dimensionally assembled nanoparticle structures inducing multiple plasmon resonances for broadband light harvesting in nanocrystalline silicon (nc-Si:H) thin-film solar cells. A three-dimensional multiscale (3DM) assembly of nanoparticles generated using a multi-pin spark discharge method has been accomplished over a large area under atmospheric conditions via ion-assisted aerosol lithography. The multiscale features of the sophisticated 3DM structures exhibit surface plasmon resonances at multiple frequencies, which increase light scattering and absorption efficiency over a wide spectral range from 350–1100 nm. The multiple plasmon resonances, together with the antireflection functionality arising from the conformally deposited top surface of the 3D solar cell, lead to a 22% and an 11% improvement in power conversion efficiency of the nc-Si:H thin-film solar cells compared to flat cells and cells employing nanoparticle clusters, respectively. Finite-difference time-domain simulations were also carried out to confirm that the improved device performance mainly originates from the multiple plasmon resonances generated from three-dimensionally assembled nanoparticle structures.

https://iopscience.iop.org/article/10.1088/0957-4484/27/5/055403/pdf

Jun-Sik Cho

Papers

A light-trapping strategy for nanocrystalline silicon thin-film solar cells using three-dimensionally assembled nanoparticle structures.