瑞典林雪平大学Feng Gao团队报道了spiro-OMeTAD的离子调节自由基掺杂用于更高效和稳定的钙钛矿太阳能电池。相关研究成果发表在2022年7月29日出版的《科学》。

研究人员用有机空穴转运体2,2 ''，7,7 '' -四(N,N-二-对甲氧基苯胺)9,9 '' -螺旋双芴(spiro-OMeTAD)获得了钙钛矿太阳能电池的记录功率转换效率（PCEs）。用吸湿锂盐和挥发性4-叔丁基吡啶对spiro-OMeTAD进行常规掺杂是一个耗时的过程，也会导致器件稳定性差。

研究人员开发了一种新的spiro-OMeTAD掺杂策略，通过使用稳定的有机自由基作为掺杂剂，离子盐作为掺杂调制器（称为离子调制自由基掺杂），避免后期氧化。研究人员实现了大于25%的PCE，并大大提高了设备在恶劣条件下的稳定性。自由基提供空穴极化子，并瞬间增加电导率和功函数（WF），离子盐通过影响空穴极化子的能量学进一步调节WF。这种有机半导体掺杂策略将电导率和WF可调性解耦，可以激发其他光电子器件的进一步优化。

附：英文原文

Title: Ion-modulated radical doping of spiro-OMeTAD for more efficient and stable perovskite solar cells

Author: 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

Issue&Volume: 2022-07-29

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.

DOI: abo2757

Source: https://www.science.org/doi/10.1126/science.abo2757