利用混合金屬與介電質材料之奈米光學結構增加太陽能電池之光吸收率

Abstract

我們提出將介電質材料覆蓋於奈米金屬球粒子的奈米結構，以增加薄膜太陽能電池之光吸收率。將不同形狀之介電質材料覆蓋於金屬奈米粒子，進而探討光學性質，發現在特定的參數底下，可以增強光在可見光頻域下的吸收率。其中，奈米金屬粒子與介電質奈米粒子達一定比例時，可以得到好的光吸收率。以二氧化矽薄膜覆蓋於周期奈米銀粒子時，光吸收率的趨勢會被二氧化矽的厚度所主導，而光吸收率也可以高於普通的周期金屬奈米粒子。厚度達一百二十奈米時，我們可以得到較佳的光吸收率。若二氧化矽薄膜覆蓋較小的銀奈米粒子，其光能量的穿透與銀奈米粒子的周期無關。利用這些物理機制以及混和材料結構的設計概念，我們可以給予未來薄膜太陽能電池表面抗反射層的結構設計方針。

We propose the structure which the silica material with different shapes covers over the periodically silver nanoparticle to enhance the optical transmission in thin film solar cells. We study the optical properties and obtain the better transmission in the visible region with the particular parameters in the structure. When the ratio of the radius of silver nanoparticles and silica nanoparticles becomes a particular value, we can obtain the good performance for enhancing the optical transmission. It is found that the trend of the photon number is dominated by the thickness of silica thin film for the structure which silver nanoparticles mantled by silica thin film. Moreover, the photon number transmission is higher than the common structure which has the rectangular arrangements for silver nanoparticles. It is interesting that the smaller silver nanoparticles have no relationship with the period of silver nanoparticles in the mantled structure with proper thickness of silica thin film. These results can be useful in the further study of design for high optical transmission nanostructure as a guideline.