2022-09-06 スウェーデン・リンショーピング大学
Postdoc Tiankai Zhang, professor Feng Gao and junior lecturer Feng Wang are part of the international research team behind the findings published in Science.Anna Nilsen
Spiro-OMeTADと呼ばれるドープされた輸送層は、記録的な電力変換効率を実現する。しかし、Spiro-OMeTADをドープするために用いられる現在の方法は、時間がかかり、ペロブスカイト太陽電池の安定性の問題を引き起こしている。
「Spiro-OMeTADの新しいドーピング戦略を用いて、開発の障害となっていたトレードオフを解消することに成功し、高効率と優れた安定性の両方を手に入れることができるようになりました」とTiankai Zhangは言う。
＜関連情報＞
- https://liu.se/en/news-item/stort-steg-narmre-stabila-hogeffektiva-perovskitsolceller
- https://www.science.org/doi/epdf/10.1126/science.abo2757
spiro-OMeTADのイオン変調ラジカルドープによる高効率で安定したペロブスカイト太陽電池の実現 Ion-modulated radical doping of spiro-OMeTAD for more efficient and stable perovskite solar cells
Tiankai Zhang,Feng Wang,Hak-Beom Kim,In-Woo Choi,Chuanfei Wang ,Eunkyung Cho ,Rafal Konefal ,Yuttapoom Puttisong ,Kosuke Terado,Libor Kobera ,Mengyun Chen,Mei Yang,Sai Bai ,Bowen Yang ,Jiajia Suo ,Shih-Chi Yang,Xianjie Liu ,Fan Fu ,Hiroyuki Yoshida ,Weimin M. Chen ,Jiri Brus ,Veaceslav Coropceanu ,Anders Hagfeldt ,Jean-Luc Brédas ,Mats Fahlman ,Dong Suk Kim ,Zhangjun Hu ,Feng Gao
Science Published:28 Jul 2022
DOI: 10.1126/science.abo2757
A radical doping approach
In perovskite solar cells, high power conversion efficiencies (PCEs) are usually obtained with an organic hole transporter called spiro-OMeTAD. This material must be doped to have sufficient conductivity and optimal work function, but the conventional process with lithium organic salts requires a long oxidation step that also affects device stability. Zhang et al. added spiro-OMeTAD biradical precursors that convert into stable organic monoradicals. Combined with ionic salts, this doping strategy formed solar cells with high PCEs (>25%) and improved stability. This approach also allows conductivity and work function to be tuned separately and could be applied in other optoelectronic devices. —PDS
Abstract
Record power conversion efficiencies (PCEs) of perovskite solar cells (PSCs) have been obtained with the organic hole transporter 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene (spiro-OMeTAD). Conventional doping of spiro-OMeTAD with hygroscopic lithium salts and volatile 4-tert-butylpyridine is a time-consuming process and also leads to poor device stability. We developed a new doping strategy for spiro-OMeTAD that avoids post-oxidation by using stable organic radicals as the dopant and ionic salts as the doping modulator (referred to as ion-modulated radical doping). We achieved PCEs of >25% and much-improved device stability under harsh conditions. The radicals provide hole polarons that instantly increase the conductivity and work function (WF), and ionic salts further modulate the WF by affecting the energetics of the hole polarons. This organic semiconductor doping strategy, which decouples conductivity and WF tunability, could inspire further optimization in other optoelectronic devices.
