成果報告書詳細
管理番号20160000000265
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(光吸収層の高品質化によるCIS太陽電池の高効率化)
公開日2016/11/16
報告書年度2015 - 2015
委託先名国立研究開発法人産業技術総合研究所
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:Research and development of the technologies to improve CIS solar cells(Improvement of the efficiency of CIS solar cells via improvement of the quality of the light absorber layer)(FY2015-FY2017) FY2015 Annual Report

The thin film solar cell with chalcopyrite Cu(In,Ga)Se2( CIGS) absorber has been widely studied. The efficiency of laboratory-level CIGS solar cells has already exceeded 21%. Chirila and co-workers demonstrated the effectiveness of post deposition treatment using KF (KF-PDT) in improving the CdS/CIGS interface quality. A high efficiency (20.4%) was achieved with KF-PDT of a polyimide substrate. It is known that the MoSe2 intermediate layer is formed at the CIGS/Mo interface. This intermediate layer makes the contact of the CIGS/Mo a favorable ohmic or quasi-ohmic type. Oxidation and aging of Mo back contacts also have been reported to affect the photovoltaic properties of CIGS solar cells fabricated on them. The oxidized Mo layer can function as a diffusion barrier for specie such as Se and the oxidation layer can affect the formation of the MoSe2 layer. In 2016, we have studied the effects of Mo surface oxidation conditions on the photovoltaic properties of CIGS solar cells fabricated by KF-PDT on soda lime glass (SLG) substrates. SLG functions as a source of alkali metals. During CIGS fabrication and KF-PDT, the alkali metals diffuse from SLG into the CIGS absorber through Mo, MoSe2, and molybdenum oxide if the surface of Mo is oxidized. Thus, the Mo surface condition could play an important role in alkali-metal diffusion. In this study, the surface oxidation conditions of the Mo back contact were varied by annealing in air or by chemical etching. First, MoSe2 formation at the CIGS/Mo interface was investigated by transmission electron microscopy. Alkali-metal depth profiles were then studied by secondary-ion mass spectroscopy (SIMS) measurement using Cs+ as the primary ion. The effects of the oxidation of the Mo surface on the photo-voltaic properties of the CIGS solar cell were then comprehensively studied, including a discussion of space charge density and minority carrier lifetime. As the results, upon the removal of the oxidized layer from the Mo surface by chemical etching, the c-axis orientation of MoSe2 tended to be random, whereas the c-axis was perpendicular when the Mo surface was oxidized. An enhancement of the diffusion of Na and K from SLG to CIGS was observed upon removing the molybdenum oxide, which functions as a barrier to alkali-metal diffusion. The varied orientation of MoSe2 can also affect the alkali-metal diffusion kinetics. The open-circuit voltage (Voc) markedly increased after removing the oxidized layer from the Mo surface, mainly as a result of an increase in carrier density in CIGS.
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