Tsutomu Miyasaka

Tsutomu Miyasaka first proposed the novel concept of perovskite solar cells, with their lightweight, flexible nature offering a vision for next-generation power sources that overturn conventional assumptions. His research efforts have focused on addressing challenges such as reducing environmental impact from lead content and improving operational lifespan. His work continues to exert a major influence on the solution of global energy issues moving forward.

Tsutomu Miyasaka introduced solar cells utilizing the groundbreaking material system known as perovskite and opened new frontiers in high-efficiency photovoltaic conversion through solution-based coating processes, contrasting with long-standing research on solar power generation based on crystalline silicon solar cells. Crystalline silicon solar cells, which emerged in the 1950s, have been refined over time to support the foundation of energy infrastructure. With a thickness of approximately 100 µm, they have become a globally widespread technology with over 20 years of long-term reliability and conversion efficiencies exceeding 26%. In contrast, perovskite solar cells, which Miyasaka proposed around 2006, possess an organic-inorganic hybrid structure and exploit the exceptional light-absorption coefficients and charge-transport properties of metal halides. The thickness required for photovoltaic conversion (excluding electrodes and substrates) is only a few micrometers or less, enabling bending and an innovative manufacturing method based on simple, low-cost printing technology. This innovation departs from conventional manufacturing methods that require large-scale vacuum equipment. More importantly, its lightweight and flexible characteristics establish a new paradigm for deploying solar power in locations where installing silicon solar cells is challenging.

Currently, silicon solar cells, which lead the global clean energy, hold a strong position due to their proven high reliability and low levelized cost of electricity (LCOE). Perovskite solar cells are attracting attention as the next-generation frontrunner that will open new markets, such as walls and mobile platforms, areas where conventional silicon-based systems could not reach. In the future, a complementary approach is anticipated in which robust silicon-based systems support the core power supply, while adaptable perovskite-based systems expand the breadth of energy provision across diverse forms. Research has reported ultra-high efficiencies exceeding 30%, surpassing the limits of silicon alone, for “tandem” solar cells that stack perovskite layers on top of silicon. They are drawing strong global interest as a key to accelerating the adoption of renewable energy while utilizing existing infrastructure.

Research is presently being conducted to enhance the stability of perovskite materials and to reduce their environmental impact, representing a critical evolutionary process for this technology to spread throughout society. Notably, Miyasaka is leading research efforts to resolve challenges toward social implementation, including the exploration of lead-free materials and the development of advanced encapsulation technologies. As further research and development led to these technological innovations, perovskite solar cells are widely expected to fulfill a critical societal role as flexible energy sources capable of turning vast spaces into power-generating assets.

Academic advancements are progressing the field of perovskite solar cells, pioneered by Miyasaka, toward the stage of practical application that supports a sustainable societal infrastructure. Therefore, the originality of this pioneering concept is held in high regard, and the dedication to addressing energy challenges is worthy of the Kyoto Prize.

References
(1) Kojima A, Teshima K, Miyasaka T & Shirai Y (2006) Novel Photoelectrochemical Cell with Mesoscopic Electrodes Sensitized by Lead-Halide Compounds (2). 210th ECS Meet. Abstr. MA2006-02: 397.
(2) Kojima A, Teshima K, Shirai Y & Miyasaka T (2009) Organometal Halide Perovskites as Visible-Light Sensitizers for Photovoltaic Cells. J. Am. Chem. Soc. 131: 6050–6051.
(3) Lee MM, Teuscher J, Miyasaka T, Murakami TN & Snaith HJ (2012) Efficient Hybrid Solar Cells Based on Meso-Superstructured Organometal Halide Perovskites. Science 338: 643–647.
(4) Singh T & Miyasaka T (2018) Stabilizing the Efficiency Beyond 20% with a Mixed Cation Perovskite Solar Cell Fabricated in Ambient Air under Controlled Humidity. Adv. Energy Mater. 8: 1700677.
(5) Singh T, Ikegami M & Miyasaka T (2018) Ambient Fabrication of 126 µm Thick Complete Perovskite Photovoltaic Device for High Flexibility and Performance. ACS Appl. Energy Mater. 1: 6741–6747.