成果報告書詳細
管理番号20120000000363
タイトル平成23年度中間年報 太陽エネルギー技術研究開発 太陽光発電システム次世代高性能技術の開発 フィルム型軽量低価格色素増感太陽電池の研究開発(高性能色素及び電極の研究開発とセル性能総合評価)
公開日2013/1/18
報告書年度2011 - 2011
委託先名国立大学法人岐阜大学
プロジェクト番号P07015
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.基準セル・モジュール作製プロセスの開発
再現性と平均効率が向上した。D149+電析ZnO評価基準ミニセルについて、プロセスと部材の最適化を行い、変換効率5.12%±0.27→5.36%±0.14、標準偏差5.0%→2.6%となった。大型電析装置、スクリーン印刷機、真空貼り合せ装置による作製環境が整い、10センチ角フィルムモジュールでは、4セル構造で変換効率2.4%、8セル構造で変換効率2.6%を確認した。電析法によるモジュール作製ではメッキ条件検討を進めており、現在1.2%程度を確認した。
2.酸化亜鉛ナノ・エネルギー構造制御技術開発
3D-TEMによる電析ZnO膜の立体ナノ構造評価と空隙率の定量化に成功し、膜構造と電池性能相関解明を進める環境が整った。エオシンY添加量の増大によるナノワイヤー微細化(5-7 nm)によるFF向上と電析温度の上昇(80℃)によるIPCEの向上を果たし、D149を用いたミニセルの変換効率が5.9%にまで向上した。
3.高効率・高耐久増感色素の開発
電析ZnO膜を用いたミニセルでの最高効率は6.2%(DN98)、DN350を用いた場合は膜厚3μmの電析ZnO膜で5.7%を達成した。
4.高効率化チューニングとボトルネック因子解明
インピーダンス測定及びSLIM-PCV測定より、ナノワイヤー微細化によるFF向上が、状態密度分布が狭くなって再結合抵抗の電圧依存性が大きくなることがその理由である一方、電析温度を上昇させた場合のIPCE向上は界面整流性の向上(電子注入効率の向上と再結合抵抗の増大)と電子拡散係数の増大に基づくことが明らかとなった。
英文要約(FY2010-FY2012) FY2011 Annual Report
The aim of this project is to industrialize low cost and light weight film-type dye-sensitized solar cells (DSSCs). The tasks of Gifu University (GU) group are to develop new materials, process technology and evaluation techniques for improving the efficiency and stability of the devices, and feed them back to Gunze Limited that is in charge of commercialization of the new solar cells. More specifically, the tasks of GU group are,
1) Process development for standard cells and modules
2)Control of nano- and energy-structures of ZnO electrode
3)Development of new photosensitizers for high efficiency and stability
4)Elucidation of bottle-neck factors and system optimization for high efficiency
(1)It is important to facilitate fabrication of cells and modules for standardize the platform for evaluation of the new materials. Laboratory-scale mass production of devices with high efficiency in high reproducibility is the goal. It was tackled by introducing 4 major changes in this FY; 1) precise control of the electrode size and position by photolithography, 2) control of impurities in the electrolyte, 3) fabrication of sealed cells in regular shapes using templates, 4) cleaning of ZnO surface and control of dye adsorption process. As a consequence, the average efficiency of 5.12% was achieved employing D149 as the sensitizer, with an improved standard deviation of 5% as compared to that of the previous method (34%).
Plastic film modules in ca. 80 × 90 mm size with 8 parallel cells were designed and fabricated. An efficiency of 2.6 % was achieved for a screen-printed ZnO particulate electrode, while it remained at 1.3% for electrodeposited ZnO, due to the limited thickness associated with the problem of film pealing.
(2)In order to achieve fine control of the nanostructure, it is highly important to grasp the three-dimensional nanostructure. 3D-TEM is an effective solution. The cross section of the film was shaped into a rod with ca. 200 nm using an FIB system to allow 180° rotation to obtain a complete tomography. From the quantitative treatment of the image, we succeeded to estimate a porosity of 44% as a typical value for the electrodeposited ZnO nanowire structure.
(3)Newly developed indoline dyes to which electron-withdrawing dicyanovinylidene group to the electron-accepting double rhodanine moiety achieved narrowing and positive shift of HOMO-LUMO at the same time. While absorption onset was extended for ca. 20 nm towards the longer wavelength than D149, the same high IPCE was achieved, thanks to the efficient dye regeneration reaction for its positive HOMO. As a consequence higher efficiencies were achieved for the new dyes, DN319 (5.0%), DN350 (5.8%) than D149 (4.7%) (employing screen-printed ZnO).
New dyes aiming high stability and easy handling were developed by chemically attaching cholic acid, used typically as additive to suppress dye aggregation, to the dye chromophore. High efficiencies were stably achieved for those dyes without addition of cholic acid, proving the usefulness of such a strategy.
(4)Increase of bath temperature for electrodeposition was found to increase the density of ZnO nanowire without changing its diameter. Such ZnO with increased density achieved high IPCE up to 90% employing D149, to achieve the highest efficiency of 5.9%. Impedance analysis and SLIM-PCV revealed that improvement of electron injection efficiency and increase of recombination resistance were the reason for this improvement.
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