2022-10-27 スイス連邦工科大学ローザンヌ校(EPFL)
研究グループは、メゾスコピック色素増感太陽電池（DSC）の光電変換性能を高めるために、新たに設計した2つの光増感色素分子のパッキングを改善する方法を開発した。この新しい光増感色素は、可視光領域全体にわたって定量的に光を取り込むことができる。この技術では、ナノ結晶のメソポーラス酸化チタンの表面に、ヒドロキサム酸の誘導体の単層をあらかじめ吸着させる。これにより、2種類の増感剤の吸着速度が低下し、二酸化チタン表面に秩序だった高密度の増感剤層が形成される。
この方法により、世界標準の模擬太陽光のもとで、初めて15.2%の電力変換効率を持つDSCを開発し、500時間以上の長期動作安定性を確認することができた。さらに、アクティブエリアを2.8 cm2に拡大することで、幅広い光量範囲において28.4%～30.2%の電力変換効率を達成し、優れた安定性を実現した。
＜関連情報＞
- https://actu.epfl.ch/news/gratzel-solar-cells-achieve-a-new-record/
- https://www.nature.com/articles/s41586-022-05460-z
ヒドロキサム酸の前吸着による増感型太陽電池の高効率化 Hydroxamic acid preadsorption raises efficiency of cosensitized solar cells
Yameng Ren,Dan Zhang,Jiajia Suo,Yiming Cao,Felix T. Eickemeyer,Nick Vlachopoulos,Shaik M. Zakeeruddin,Anders Hagfeldt & Michael Grätzel
Nature Published:26 October 2022
DOI:https://doi.org/10.1038/s41586-022-05460-z
Abstract
Dye-sensitized solar cells (DSCs) convert light into electricity using photosensitizers adsorbed on the surface of nanocrystalline mesoporous titanium dioxide (TiO2) films along with electrolytes or solid charge-transport materials1-3. They possess many features including transparency, multicolor and low-cost fabrication, and are being deployed in glass facades, skylights and greenhouses4. Recent development of sensitizers5-10, redox mediators11-13 and device structures14 has improved the performance of DSCs, particularly under ambient light conditions14-17. To further enhance its efficiency, it is pivotal to control the assembly of dye molecules on the surface of TiO2 that favors charge generation. Here, we report a route of pre-adsorbing a monolayer of a hydroxamic acid derivative on the surface of TiO2 to improve the dye molecular packing and photovoltaic performance of two newly-designed co-adsorbed sensitizers that harvests light quantitatively across the entire visible domain. The best performing cosensitized solar cells exhibited a power conversion efficiency (PCE) of 15.2% (independently confirmed 15.2%) under standard air mass 1.5 global simulated sunlight, and showed long-term operational stability (500 hours). Devices with a larger active area of 2.8 cm2 exhibited PCE of 28.4 % to 30.2 % over a wide range of ambient light intensities along with high stability. Our findings pave the way for facile access to high performance DSCs and offer promising prospects for applications as power supply and battery replacement for low-power electronic devices18-20 that use ambient light as their energy source.
