Controlled Redox of Lithium-Ion Endohedral Fullerene for Efficient and Stable Metal Electrode-Free Perovskite Solar Cells

Il Jeon; Ahmed Shawky; Hao-Sheng Lin; Seungju Seo; Hiroshi Okada; Jin-Wook Lee; Amrita Pal; Shaun Tan; Anton Anisimov; Esko I Kauppinen; Yang Yang; Sergei Manzhos; Shigeo Maruyama; Yutaka Matsuo

doi:10.1021/jacs.9b06418

Controlled Redox of Lithium-Ion Endohedral Fullerene for Efficient and Stable Metal Electrode-Free Perovskite Solar Cells

J Am Chem Soc. 2019 Oct 23;141(42):16553-16558. doi: 10.1021/jacs.9b06418. Epub 2019 Sep 30.

Authors

Il Jeon^{1

2}, Ahmed Shawky^{1

3}, Hao-Sheng Lin¹, Seungju Seo¹, Hiroshi Okada¹, Jin-Wook Lee^{4

5}, Amrita Pal⁶, Shaun Tan⁵, Anton Anisimov⁷, Esko I Kauppinen⁸, Yang Yang⁵, Sergei Manzhos⁹, Shigeo Maruyama^{1

10}, Yutaka Matsuo^{1

11}

Affiliations

¹ Department of Mechanical Engineering , The University of Tokyo , 7-3-1 Hongo , Bunkyo-ku, Tokyo 113-8656 , Japan.
² KU-KIST Green School Graduate School of Energy and Environment , Korea University , 145 Anam-ro , Seongbuk-gu, Seoul 02841 , Korea.
³ Nanomaterials and Nanotechnology Department, Advanced Materials Division , Central Metallurgical R&D Institute (CMRDI) , P.O. Box 87 , Helwan, Cairo 11421 , Egypt.
⁴ SKKU Advanced Institute of Nanotechnology (SAINT) and Department of Nanoengineering , Sungkyunkwan University , Suwon 16419 , South Korea.
⁵ Department of Materials Science and Engineering and California Nano Systems Institute , University of California , Los Angeles , California 90095 , United States.
⁶ Department of Mechanical Engineering , National University of Singapore , Block EA #07-08, 9 Engineering Drive 1 , Singapore 117576 , Singapore.
⁷ Canatu, Ltd. , Konalankuja 5 , FI-00390 Helsinki , Finland.
⁸ Department of Applied Physics , Aalto University School of Science , P.O. Box 15100 , Aalto, Espoo FI-00076 , Finland.
⁹ Centre Énergie Matériaux Télécommunications , Institut National de la Recherche Scientifique , 1650 boulevard Lionel-Boulet , Varennes Quebec J3 × 1S2 , Canada.
¹⁰ Energy NanoEngineering Lab. , National Institute of Advanced Industrial Science and Technology (AIST) , Tsukuba 305-8564 , Japan.
¹¹ Institute of Materials Innovation, Institutes of Innovation for Future Society , Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8603 , Japan.

PMID: 31529952
DOI: 10.1021/jacs.9b06418

Abstract

High efficiency perovskite solar cells have underpinned the rapid growth of the field. However, their low device stability limits further advancement. Hygroscopic lithium bis(trifluoromethanesulfonyl)imide (Li⁺TFSI^-) and metal electrode are the main causes of the device instability. In this work, the redox reaction between lithium-ion endohedral fullerenes and 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenylamine)-9,9'-spirobi-fluorene (spiro-MeOTAD) was controlled to optimize the amount of oxidized spiro-MeOTAD and antioxidizing neutral endohedral fullerenes. Application of this mixture to metal-free carbon nanotube (CNT)-laminated perovskite solar cells resulted in 17.2% efficiency with a stability time of more than 1100 h under severe conditions (temperature = 60 °C, humidity = 70%). Such high performance is attributed to the uninhibited charge flow, no metal-ion migration, and the enhanced antioxidizing activity of the devices.