應用軟性電子元件製備及表面粗糙化技術於可撓式高效率單晶矽太陽能電池

Abstract

近數十年來，由於面臨能源枯竭和氣候變遷警訊所導致油價不斷上漲以及溫室效應的問題，因此以太陽能電池為主要發展的綠能科技產業開始備受矚目。太陽能電池主要是利用光伏效應將太陽能直接轉換成可用電能的無汙染裝置，目前太陽能電池市場主要以單晶矽、多晶矽以及非晶矽三大種類為主，其中以單晶矽太陽能電池的光電轉換效率最高。然而，隨著半導體科技產業發達以及生活便利之眾多需求，結合軟性電子元件技術和太陽能電池的發展已如火如荼的展開，其中以非晶矽和有機材料使用塑膠基板當作基材所製成的可撓曲軟性太陽能元件最為廣泛，但非晶矽太陽能電池的光電轉換效率相較於一般不可撓的單晶矽基材元件為差，且塑膠基板無法耐高溫因此不適用於一般工業化製成。因此，倘若可以研發出可撓曲的單晶矽高效能太陽能電池，對於未來的應用性將可大幅提升，對於綠能產業也將是一大突破。本研究主要以單晶矽作為基材,使用化學蝕刻技術將其製備為超薄可撓式矽薄片，並針對上電極最佳化，加上表面粗糙化技術以及氮化矽鈍化層兼抗反射層之設計，使入射光可在超薄可撓式的單晶矽太陽能電池元件內做最大之吸收利用，可以成功達到13.8 %的光電轉換效率。本研究結果顯示，此元件不僅擁有輕薄易攜帶的優勢，且其可撓式的特性將可貼附於各種凹凸曲面上。因此，結合單晶矽優越的光電轉換效率以及軟性可撓式的優勢，對於未來在日常生活中的實質應用範圍將可以更為廣泛。

During the last couple of decades, people have pay more and more attention to photovoltaic technologies in virtue of facing the nature resources crisis resulting in oil price increment as well as the ubiquitous signs of climate change caused by the greenhouse effect. Basically, a photovoltaic cell is a zero pollution device which can convert the energy of sunlight directly into useful electricity by the photovoltaic effect. Nowadays, there are three major kinds of commercial-grade solar photovoltaics on the commercial photovoltaic market, including single-crystalline, poly-crystalline and amorphous structure type. Among all the types mentioned above, single-crystalline silicon photovoltaic cells especially have the superior conversion efficiency. Recently, the evolution of photovoltaic cells combining flexible electronics with solar photovoltaic technologies rapidly grows up so as to satisfy the flexibility and elasticity needs. In general, amorphous and organic flexible photovoltaic devices base on plastic substrates are common in the traditional flexible industry but supply rather poor electrical properties. Even worse, the plastic substrates provide extremely low endurable under the high temperature ambience in industrial procedure. Therefore, it will make a breakthrough if it is able to develop bendable single-crystalline photovoltaic cells which can compatible with general procedure but also provide highly electrical properties. This study aims to fabricate the bendable solar photovoltaic by practical and reproducible method. In detail, the bendable solar photovoltaic was manufactured on the 30 □m-thickness single-crystalline silicon chip which was achieved by treating with chemical etching process. Additionally, our design of the flexible device incorporates optimal compute of front contact, with some common techniques to reduce light trapping including surface texturization and antireflection layer deposition which can minimize the reflectivity losses of the incident light. By applying as-mentioned methods, the bendable device gives conversion efficiency up to 13.8 %. Moreover, the outstanding lightweight superiority and mechanical flexibility of these flexible ultrathin devices utilize easily-achieved integrated applications to various product surfaces and pave the way for portable purpose. With the reducing usage of required semiconductor material and excellent mechanical flexibility, these novel flexible solar photovoltaics are ready to satisfy with market demands and promote competitiveness in the mass production and commercial market.