Speakers

Prof. Tsutomu MIYASAKA completed the Graduate School of Engineering, the University of Tokyo in 1981 (Doctor of Engineering). He was a senior researcher at the Ashigara Research Institute of Fuji Photo Film Co., Ltd. in 1981-2001, and has been a professor at the Graduate School of Engineering, Toin University of Yokohama (TUY) since 2001, serving as the Dean of the Graduate School of Engineering from 2006 to 2009. From 2005 to 2010, he was also a guest professor at the Graduate School of Arts and Sciences, the University of Tokyo. He founded Peccell Technologies Co., Ltd. in 2004 and is the CEO. He is currently a project professor at TUY and a fellow of Research Center of Advanced Science and Technology, the University of Tokyo. His research specializes in photoelectrochemistry and hybrid photovoltaic cells, especially halide perovskite solar cells. Awards include Rank Prize in Optoelectronics (2021), Clarivate Analytics Citation Honor Award (2017), Japan Society of Applied Physics Achievement Award (2019), Chemical Society of Japan Award (2017), PVSEC Hamakawa Award (2017), Ichimura Academic Award (2020), etc.

Perovskite Solar Cells that Challenge the Pinnacle of Printable Photovoltaic Device

Abstract

Since our first discovery of perovskite solar cell (PSC) in 2006-2009, enormous efforts have been put into different aspects of PSCs and the progress has been incredibly fast leading to the present highest power conversion efficiency (PCE) of 25.7%. The current R&Ds of PSCs are focused on interfacial engineering for defect passivation, compositional engineering for improved durability, and fabrication of large area modules and muti-junction tandem cells.¹ We have been tackling the method of interfacial passivation with functional organic molecules, which enables high voltage output (close to theoretical limit) in photovoltaic performance with PCE>22%.² Although the photovoltaic performance has improved, the stability of the devices still remains an issue to be improved. Use of organic cations in halide perovskites and diffusible dopants in hole transport materials (HTMs) are responsible for low stability of perovskites at high temperatures (>120^oC). In this respect, all-inorganic compositions of perovskite and use of dopant-free HTMs are highly desired. We are currently focus our R&D on inorganic CsPbX₃ (X=I, Br) perovskites in combination of dopant-free HTMs.² By compositional changes at hetero-junction interfaces, CsPbI₂Br PSCs achieved PCEs of >17% under 1 sun and >34% under indoor LED illumination.³ As inorganic perovskites, lead-free compositions such as Ag-Bi halides have become an important target for achieving environmentally kind PSCs.⁴

Applications of PSCs in space environments are also promising because thin perovskite photovoltaic films demonstrate high stability and tolerance against exposure to high energy particle irradiations (proton and electron beams).⁵ Thin absorbers (<500 nm) avoid accumulation of particles and due to intrinsic defect tolerant nature of perovskites, radiation-induced collision damage is highly suppressed. Based on our current R&Ds, future perspectives of perovskite photovoltaics will be presented.

Reference

1. T. Miyasaka, editor, Perovskite Photovoltaics and Optoelectronics ―From Fundamentals to Advanced Applications―, Wiley-VCH, Weinheim, 2021, ISBN: 978-3-527-34748-3.
2. G. M. Kim, H. Sato, Y. Ohkura, A. Ishii, and T. Miyasaka, Adv. Energy Mat. 2022, 12, 2102856.
3. Z. Guo, A. K. Jena, I. Takei, M. Ikegami, A. Ishii, Y. Numata, N. Shibayama, T. Miyasaka, Adv. Func. Mat. 2021, 31, 2103614.
4. T. Miyasaka, A. Kulkarni, Gyu Min Kim, Senol Öz, A. K. Jena, Adv. Energy. Mat. 2019, 1902500.
5. Y. Miyazawa, M. Ikegami, H.-W. Chen, T. Ohshima, M. Imaizumi, K. Hirose, T. Miyasaka, iScience 2018, 2, 148.