奈米壓印製作奈米結構及其於混合型太陽能電池之應用

Abstract

近年來，混合型太陽能電池(Hybrid solar cell)的發展，結合無機材料和有機材料太陽能電池的優點，其優勢在於使用簡單和低溫製程的方式製作元件，降低成本。此論文使用無機材料_矽作為元件基板，以PEDOT:PSS ( Poly(3,4-ethylenedioxythiophene) Polystyrene sulfonate )導電高分子作為有機材料，研究主要目的在於：以低溫、低成本的製程方式，在單晶矽基板上製作出奈米結構，降低反射率，提升混合型太陽能電池的光電轉換效率。 其中，使用紫外光固化式奈米壓印技術，在矽基板上修飾出週期性奈米結構，經由增加表面的抗反射效果，增加吸收太陽光而增加光電流的產生。再者，單晶矽與導電高分子的接觸表面積增加，也增加電子電洞對分離的機會。因此，表面的奈米結構不僅有抗反射的效果，也有增加徑向接面的優點，週期600奈米之太陽能電池的短路電流最佳可至34.8 mA/cm2，光電轉換效率可達11.45%。

In recent years, highly efficient organic/inorganic hybrid solar cells were developed due to their low-temperature fabrication and low-cost processes. However, loss in light absorption due to the surface reflection is still the major concern for solar cells. It is known that the similar refractive index between interface result in the lower reflectivity. The pyramid-shaped nanostructures fabricated on the surface are able to provide graded refractive index and, therefore, reduce the surface reflection and increase light absorption. In this report, we modified a Si substrate surface with pyramid nanostructures by combining the UV-curing nanoimprint lithography and chemical wet etching processes. The nanostructures improve anti-reflection effect and provide radial junction architecture that have enhanced light absorption and carrier collection efficiency. Compared with a planar device , the short circuit current density of the nanostructured device increase from 24.5 mA/cm2 to 34.8 mA/cm2.