大面積銅銦鎵硒太陽能電池 轉移至任意基板的製程研究

Development of Large scale Lift-Off Approach for Cu(In,Ga)Se2 Solar Cells on Arbitrary Substrates

曾冠鈞(Tseng, Kuan Chun)

指導教授 ： 闕郁倫

國立清華大學/工學院/材料科學工程學系/碩士(2015年)

摘要

銅銦鎵硒(Cu(In,Ga)Se2,CIGS)為一現今熱烈發展的太陽能電池吸收層材料，其優點具有直接能隙，有相當高的吸收係數，可製作成薄膜太陽能電池，減少材料使用，薄膜厚度的太陽能電池更可適用於可撓式基板及可攜式裝置。然而，高效率CIGS於成長時需要經歷一段高溫硒化(約攝氏600度)的反應過程，而部分可撓式基板無法承受如此高溫的反應溫度因而限制了可撓式CIGS的應用。有鑑於此，本研究開發成長後轉移元件的方式，避免了可撓式基板經歷高溫硒化的製程，可以成功的將CIGS應用在各式可撓式基板上。
　　轉移後的CIGS透過掃描式電子顯微鏡觀察其表面及橫截面，皆呈現了與轉移前一致的結構，拉曼光譜分析證實了轉移後的CIGS與轉移前一致的振動能。X光繞射分析及光激發分析顯示了CIGS晶格有些微的錯置，但仍舊保持良好特性。電性分析表現了近70％的光轉換效率仍能維持。
　　此研究所開發的方法不但可以將CIGS應用至更廣泛的可撓式基板上，原本成長於不銹鋼基板因製程高溫而導致的鐵擴散效應也可避免，更可應用於除了CIGS以外的太陽能電池元件。此製程更因製程步驟簡單，可大面積處理，便於應用於工業化製程。

關鍵字

銅銦鎵硒 ； 可撓式 ； 大面積

並列摘要

To date, 21.7 % is the highest reported efficiency for inorganic Cu(In,Ga)Se2 (CIGS) thin-film photovoltaic solar cells (PV). However, the high temperature post-selenization process used in the fabrication of CIGS restricts its application on variety of low cost and flexible device substrates; in turn impeding the use of CIGS based PV in the next generation of consumer electronic products. In this work, a process enabling the direct transfer of conventional soda-lime glass (SLG) based CIGS devices onto arbitrary substrates has been developed and demonstrated. Raman analysis is performed to examine the material characteristics after the transfer process showing no significant differences, while Photoluminescence (PL) and X-ray Diffraction (XRD) show little distortion in the film crystallinity. Between the pre and post-transferred CIGS devices, 70% of power conversion efficiency is maintained. This approach utilizes a chemical-mechanical polishing (CMP)-like procedure to etch away the SLG used in the regular CIGS device structure, thus allowing the remaining device to be transferred to arbitrary substrates. SEM revealed the quality of CIGS films remain the same after the etching procedure. We demonstrate the transfer of our CIGS devices onto three different kinds of flexible substrate (Stainless steel, polyimide (PI) and paper) to establish the flexibility of our method. We believe that this approach can not only further stimulate the development of low cost flexible thin film solar cells, but also benefit the broader field of flexible electronics in general.

並列關鍵字

CIGS ； Large scale ； transfer ； flexible

參考文獻

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