本文へジャンプ

成果報告書詳細
管理番号20160000000267
タイトル*平成27年度中間年報 高性能・高信頼性太陽光発電の発電コスト低減技術開発 太陽電池セル、モジュールの共通基盤技術開発 CIS太陽電池高性能化技術の研究開発(バンド制御による再結合パッシベーション技術の開発)
公開日2017/4/8
報告書年度2015 - 2015
委託先名立命館大学
プロジェクト番号P15003
部署名新エネルギー部
和文要約
英文要約Title: Passivation technology by band alignment control

Cu(In,Ga)(S,Se)2 (CIGSSe) solar cell on soda-lime glass (SLG) substrate is promising for the high conversion efficiency (Eff) thin-film solar cell with low manufacturing costs. To boost efficiency by increasing Voc, the deacrease in carrier recombination at pn-juction by reducing interface defect density and carrier separation by band engineering is important. In this work, we work on band engineering by Zn-based ternaly compound buffer and transparant conductive oxide (TCO) fabricated by soft method of Metal Organic Chemical Vapor Deposition (MOCVD). In this fiscal year (FY2015), we introduced MOCVD system for Zn-based ternaly compound films. Before using TCO by MOCVD, the optimization of surface treatment of CIGSSe surface and buffer layer combination were performed using conventional ZnO/ZnO:Al (AZO) layers fabricated by sputtering. Since the sputtering damage on CIGSSe surface decreases the cell performances, CdS buffer layer normally used in CIGSSe solar cell plays a role in protecting the sputtering damages after ZnO and AZO depositions by sputtering. However, there is the disadvantage of CdS layer. The CdS buffer layer absorbs light with a wavelength shorter than 520 nm because its band-gap energy (Eg) of 2.4 eV. Therefore, to increase short-circuit current density of the solar cell, Zn-compound buffer with larger Eg is used as alternative to CdS buffer layer for high photovoltaic performances. A ZnS(O,OH) layer deposited by chemical bath deposition (CBD) is considered as one of the most intriguing choices for the Zn-compound buffer for CIGSSe solar cell with high Eff. In the research, it is shown that the Eff of CIGSSe solar cell with 50 nm-thick ZnS(O,OH) buffer layer is 16.5%, which is lower than 18.3%-efficient CIGSSe solar cell with 50 nm-thick CdS buffer layer. The result implies that CdS buffer layer has better capability of preventing sputtering damage on CIGSSe surface than ZnS(O,OH) buffer layer. As a result, to decrease the sputtering damage, multi-buffer layer of ZnS(O,OH)/thin-CdS stack layer is proposed and adopted as a new alternative buffer layer in this work. 50 nm-thick ZnS(O,OH)/10 nm-thick CdS/CIGS solar cell is thus fabricated. With thin CdS layer (10 nm), open-circuit voltage and fill factor are improved owing to decrease in sputtering damage and Jsc is increased due to ZnS(O,OH) layer with large Eg of 3.8 eV as compared with that of CdS layer (2.4 eV). Ultimately, Eff of 18.6% for CIGSSe solar cell with multi-buffer layer of ZnS(O,OH) (50nm)/CdS (10 nm) is achieved, which is higher that Eff of 18.3% for CIGSSe solar cell with CdS buffer layer.
ダウンロード成果報告書データベース(ユーザ登録必須)から、ダウンロードしてください。

▲トップに戻る