Single-Walled Carbon Nanotubes and Hetero-Nanotubes for Perovskite Solar Cells

Abstract

Single-walled carbon nanotubes (SWCNT), graphene, and fullerene (C 60 and PCBM) are very efficiently used in organic-inorganic Perovskite solar cells [1,2]. A film of carbon nanotubes or graphene can be the practical replacement of ITO for the flexible transparent electrode of inverted perovskite solar cells [3]. Doping of SWCNT is essential for high performance solar cells through increased in-plane film conductivity and energy level adjustment. Since p-doping is easier than n-doping, it is more practical to use SWCNT electrode in the hole-transport side. Hence, we have developed the normal type perovskite solar cells composed of ITO/ETL/MAPbI 3 /(HTL)/SWCNTs. The use of SWCNT as the top electrode instead of metal electrode is also enhances the stability of PSCs by removing the metal-ion migration, and considerably reduces the fabrication cost, and suitable for the development of tandem system. The normal-type perovskite solar cell, composed of ITO/C 60 /MAPbI 3 /SWCNTs, can achieve a PCE of 17 % with spiro-MeOTAD as dopant (or HTL) to SWCNTs [4]. The better performance of solar cells can be obtained by tuning of energy level of SWCNT with Trifluoromethanesulfonic acid (TFMS) doping. For 2D/3D FACsPbI 3 system we have reached PCE of 17.6% [5]. Recently, we have developed further by using high concentration of hole-transporting material [6]. For MAPbI 3 system, we have obtained the highest PCE of 18.8%. This PCE is higher than that of the metal electrode-based control devices, which gave a PCE of 18.1%. Finally, the ultimately inorganic stable doping of SWCNT could be possible by using the one-dimensional van der Waals hetero-nanotubes [7]. We have synthesized the coaxial few-layer hexagonal boron nitride nanotube (BNNT) around a single-walled carbon nanotube (SWCNT); SWCNT@BNNT. Then, the further coating of coaxial MoS 2 nanotubes results SWCNT@BNNT@MoS 2 NT. The inner SWCNT and outer MoS 2 NT are electrically coupled through a few layer BNNT. This new structure shown in Fig. 1 is expected to give extra functionality, durability in the solar cell devices. Part of this work was supported by JSPS KAKENHI Grant Numbers JP15H05760, JP18H05329. References: [1] I. Jeon, Y. Matsuo, S. Maruyama, Topics Curr. Chem., 376:4, (2018)1. [2] I. Jeon, R. Xiang, A. Shawky, Y. Matsuo, S. Maruyama, Adv. Energy Mater., (2019)1801312. [3] I. Jeon, J. Yoon, N. Ahn, M. Atwa, C. Delacou, A. Anisimov, E. Kauppinen, M. Choi, S. Maruyama, Y. Matsuo, J. Phys. Chem. Lett., 8 (2017) 5395. [4] N. Ahn, I. Jeon, J. Yoon, E. I. Kauppinen, Y. Matsuo, S. Maruyama, M. Choi, J. Mater. Chem. A 6 (2018) 1382. [4] I. Jeon, S. Seo, Y. Sato, C. Delacou, A. Anisimov, K. Suenaga, E. I. Kauppinen, S. Maruyama, Y. Matsuo, J. Phys. Chem. C, 121 (2017) 25743. [5] J.-W. Lee, I. Jeon, H. Lin, S. Seo, T.-H. Han, A. Anisimov, E. I. Kauppinen, Y. Matsuo, S. Maruyama, Y. Yang, Nano Lett., 19 (2019) 2223. [6] I. Jeon, A. Shawky, A. Anisimov, E. I. Kauppinen, Y. Matsuo, S. Maruyama, submitted (2019). [7] R. Xiang, T. Inoue, Y. Zheng, A. Kumamoto, Y. Qian, Y. Sato, M. Liu, D. Gokhale, J. Guo, K. Hisama, S. Yotsumoto, T. Ogamoto, H. Arai, Y. Kobayashi, H. Zhang, B. Hou, A. Anisimov, Y. Miyata, S. Okada, S. Chiashi, Y. Li, E. I. Kauppinen, Y. Ikuhara, K. Suenaga, S. Maruyama, arXiv:1807.06154 (2019). Figure 1