成果報告書詳細
管理番号20110000000603
タイトル*平成22年度中間年報 最先端研究開発支援プログラム/低炭素社会に資する有機系太陽電池の開発/低コスト色素増感太陽電池の製造と発電実証試験
公開日2011/6/29
報告書年度2010 - 2010
委託先名シャープ株式会社
プロジェクト番号P09026
部署名新エネルギー部
和文要約和文要約等以下本編抜粋:1. 研究開発の内容及び成果等 サブテーマ【13】~2「革新的ローコスト色素増感太陽電池技術の研究開発」において、透明導電膜(TCO)付きガラス基板を使用しない、TCOレス構造色素増感太陽電池に関する研究開発を行う。以下、実施した具体的な開発内容および今年度の進捗を報告する。
(1) 開発内容
TCOレス構造のセルは、従来構造の色素増感太陽電池(DSC)のセルと比較して短絡電流密度(Jsc)が10%程度低下するとの報告がある[1][2]。一方、理論的には、TCOを使用しないTCOレス構造は、TCOの光吸収がなくなるため、従来のDSC構造よりもセル内部への入射光量が増大し、Jscの増加が期待できる。
現在、このJsc低下に関する課題は解明されておらず、この問題をクリアできれば、革新的ローコスト色素増感太陽電池の実現に向けてTCOレス構造の開発が極めて重要な意義を持ってくる。今年度は、Jsc低下に関する課題解決の糸口とすべく、【1】Jsc低下メカニズムの解明を実施した。また、TCOレス構造は、多孔質酸化チタン(TiO2)膜上に集電電極を形成する構造である。TiO2の表面形状は、電極のシート抵抗に大きく影響を与えるため、【2】TCOレス構造における最適な集電電極モフォロジーの特定とその作製条件を抽出する検討も行った。
英文要約Title: Funding Program for World-Leading Innovative R&D on Science and Technology / Development of organic photovoltaics toward a low-carbon society / Development of the manufacturing technology of low-cost dye sensitized solar cell and actual proof test of power generation:New Technology Development Center Sharp Corporation.
Introduction:The purpose of this research is the development of a dye-sensitized solar cell (DSC) without a transparent conducting oxide (TCO) glass. [Target (at the end of FY2011)] 1. Clarification of the degradation mechanism of a short circuit current density of a TCO-less cell 2. Clarification of technical issues inherent in a TCO-less structure: Experimental and results: 1. Clarification of the degradation mechanism of a short circuit current density of a TCO-less cell: A TCO less cell consists of a glass, a TiO2/dye, a cathode electrode, an electrolyte, and a counter electrode. The cathode electrode is formed on the porous TiO2 layer. The major differences between the TCO-less cell and a conventional DSC are a) the absence of the TCO layer on the glass at the irradiation side, and b) the existence of the cathode electrode on the porous TiO2 layer. It is reported that the short circuit current density of a TCO-less cell becomes lower than that of a conventional DSC. We confirmed this time that the short circuit current density (Jsc) of the TCO-less cell reduced by 38% of that of the conventional DSC. In order to investigate the reason for the Jsc degradation, the internal resistance analysis of TCO-less cells by electrochemical impedance spectroscopy (EIS) was carried out. As a result, the electron diffusion coefficient of the TCO-less cell was drastically decreased. Through the analysis of EIS, a new component of impedance at the frequency dependence was observed among TCO-less cells. It was also found that this component was lost depending on the TiO2 layer structures. The cross-sectional views of these samples by scanning electron microscopy (SEM) suggest the importance of the interface design of the layered structure. Thereby, Jsc reduction ratio could be reduced by 21% by changing the TiO2 layer structure. Furthermore, the optical analysis of TCO-less cells and conventional DSCs was performed. It was found that the reflectivity differences between TCO-less cells and conventional DSCs were ca. 2%; it is mainly due to a higher refractive index of a TCO layer than that of a glass. Consequently, out of a degradation of 38%, it became clear that 21% came from the porous TiO2 layer structure, and that 2% came from the difference of a refractive index between a TCO layer and a glass substrate. Through these studies, we concluded that the Jsc degradation ratio can be improved up to 15% (38%-23%). 2. Clarification of technical issues inherent in a TCO-less structure: A cathode electrode of a TCO-less cell has two functions, which are the collection of electrons and the pathways of electrolyte materials. Thus, the cell performance is influenced by the states of the cathode electrode. We firstly tried to observe the fabrication dependence of the cathode electrode by changing its deposition rate. The faster the deposition rate became, the smaller both the particle size of the porous electrode material and its pore size became, which were confirmed by SEM measurement. Also, by increasing the deposition ratio, the sheet resistance of the electrode was decreased. It is considered that the decrease of the sheet resistance is due to the improved contact of the electrode particles because of their small particle sizes and pore ones.
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