二氧化矽奈米粒子抗反射層與降轉螢光應用於單晶矽太陽能電池

Abstract

抗反射層在光電元件上扮演著一個很重要的角色，因為短路電流的增強可以經由減少光的反射來達成。本論文的研究方向為利用介電奈米粒子做為抗反射層以及利用螢光粒子來增強吸收效率。 我們成功研究出能夠有效率的塗佈二氧化矽奈米粒子至經過表面修飾以及單層膜氮化矽抗反射塗佈的單晶矽晶圓的方式。我們也同時進行了將二氧化矽以及聚苯乙烯奈米粒子塗佈在相同單晶矽晶圓上的理論模擬計算。本論文的成果成功的展現了介電奈米粒子在單晶矽晶圓上的抗反射能力。單晶矽晶圓在300 nm至1200 nm的反射率皆獲得顯著的下降，在450 nm至600 nm則顯露出了些許的持平。 此外我們還將螢光粒子應用在單晶矽太陽能電池上以提升效率。Ba2SiO4: Eu2+ (5%)螢光粒子可將單晶矽太陽能電池吸收效率較差的紫外光轉換成可見光，以提升紫外光應用價值。塗佈上Ba2SiO4: Eu2+ (5%)螢光粒子的單晶矽太陽能電池提升了約0.75%的光轉換效率。

Anti-reflection coating plays an important role in photovoltaic devices because the enhancement in short circuit current can be easily achieved by reducing the surface reflectance. Works reported in this thesis aim at the anti-reflection performance of spin-coated dielectric nanoparticles on Si wafers and the absorption enhancement of Si solar cells using phosphors. In the first part, we developed a new method that targeted at achieving monolayer (ML) silica nanoparticles on a textured single crystalline silicon (c-Si) wafer. We simulated the anti-reflection properties on two types of dielectric nanoparticles (silica and polystyrene) deposited on a textured c-Si wafer covered with an 80 nm Si3N4 thin film. Our results clearly demonstrated the advantages of combining dielectric nanoparticles with the textured c-Si substrate on the improvement of the surface anti-reflection properties. With the nanoparticle coating, reflectance of the textured c-Si wafer in the range of 300 nm to 1200 nm was decreased with slight compensation between 450 nm to 600 nm. In the second part, we applied phosphors to enhance c-Si solar cell’s conversion efficiency by absorbing the UV light and down-shifted to the visible, where the cell has an optimal response. The conversion efficiency of the c-Si solar cell was increased by nearly 0.75% using the phosphor down-shifting.