Multiscale Study of Plasmonic Scattering and Light Trapping Effect in Silicon Nanowire Array Solar Cells
Update: 2018-02-24 09:11:14      Author:

Nanometallic structures that support surface plasmons provide new ways to confine light at deep-subwavelength scales. Plasmonics has emerged as a new technology with expanding applications in materials and device research. Experiments have demonstrated that the strong field localization of surface plasmons can effectively increase the optical path length and achieve light confinement in nanostructured solar cells. In this work, the effect of light scattering in nanowire array solar cells is studied by a multiscale approach combining classical electromagnetic (EM) and quantum mechanical simulations. A photovoltaic device is constructed by integrating a silicon nanowire array with a plasmonic silver nanosphere. (Figure 1) The light scatterings by plasmonic element and nanowire array are obtained via classical EM simulations, while current-voltage characteristics and optical properties of the nanowire cells are evaluated quantum mechanically.


Fig.1 Field enhancement distribution for (a) the single nanowire solar cell, (b) the 8-nanowire array solar cell, and (c) the 16-nanowire array solar cell. Squares represent the regions where the nanowire photoactive components are located.


Fig.2 Current density per nanowire versus applied voltage of the photovoltaic devices with different numbers of surrounding nanowires under illumination of monochromatic light frequency of 3.4 eV.

In this work, ChiYung Yam’s group in CSRC in collaboration with Lingyi Meng in Xiamen University applied a multiscale QM/EM method[1,2] to study the performance of plasmonic devices that contain vertically aligned silicon nanowire arrays and silver nano- spheres.[3] Combining a classical EM description of plasmonic nanostructure and QM treatment of photoactive component, device performance and optical parameters of the nanowire array-based photovoltaic devices are determined. The light confinement effect due to nanowire array geometry and metallic nanoparticle is first obtained, and the actual device performance is then simulated quantum mechanically. The incorporation of metallic nanosphere leads to enhancement of light absorption in the device and results in dramatic improvement of PCE. The light trapping effect due to the nanowire array architecture was further investigated. Remarkably, it is shown that there exists an optimal nanowire number density in terms of optical confinement and solar cell PCE. To further improve the performance, plasmonic structures with different materials, shapes, sizes, and geometrical arrangements can be used for broadband plasmonic absorption. The present work demonstrates the multiscale QM/EM method as an efficient simulation tool for studying nanoscale optoelectronic devices. This is useful for understanding the mechanism of their energy conversion and helpful for improving the design of next- generation solar cells.


Fig.3 Schematic diagram of silicon nanowire solar cells. (left) Averaged enhancement factors of nanowire solar cells marked in Figure 2 for devices with different nanowire densities. (right)


[1]     Lingyi Meng, ChiYung Yam, Yu Zhang, Rulin Wang and GuanHua Chen J. Phys. Chem. Lett. 6, 4410 (2015).

[2]     ChiYung Yam, Lingyi Meng, Yu Zhang and GuanHua Chen, Chem. Soc. Rev. 44, 1763 (2015).

[3]     Lingyi Meng, Yu Zhang and ChiYung Yam, J. Phys. Chem. Lett. 8, 571 (2017).

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