15

Japan Academy Prize to:
Tsutomu Miyasaka
Specially Appointed Professor,
Toin University of Yokohama
for “Development of Organo-Metal Perovskite-Based
Organic-Inorganic Hybrid Solar Cells”

Outline of the work:
Dr. Tsutomu Miyasaka has made a significant contribution to the field of solar energy bydiscovering organo-lead halide compounds as absorbers for perovskite solar cells, which exhibit
energy conversion eﬃciencies comparable to those of the most eﬃcient crystalline silicon solar
cells. His research focuses on the development of new perovskite materials to enhance eﬃciency
and device stability. Unlike commonly known metal oxides, the perovskite crystals utilized in solar cells are metal halides with an ABX3 composition, typically comprising an organic-inorganic
composite compound CH3 NH3 PbX3 (where Pb denotes lead). These ionic crystals can easily
form semiconductor films when the source liquid solution is coated on an electrode substrate anddried.
In 2009, Dr. Miyasaka published the inaugural report on photoelectric conversion using
metal halide perovskites in Journal of American Chemical Society, marking a pivotal moment in
the field. Subsequent research, including a 2012 paper in Science, demonstrated that a solidified
layered structure of perovskite photovoltaic cells could achieve conversion eﬃciencies exceeding
10%. This groundbreaking work spurred global research eﬀorts, leading to rapid improvements
in eﬃciency. In recognition of his influential contributions, Clarivate Analytics (formerly Thomson Reuters) honored Miyasaka with the Citation Laureates award in 2017 for his highly cited
papers, and in 2022, he received the Rank Prize in the UK.
Halide perovskites are distinguished by their exceptional optical properties and a physicalcharacteristic known as “defect tolerance,” which substantially mitigates defect-assisted charge
recombination. This property ensures a high output voltage for power generation, thereby enabling high conversion eﬃciency. Dr. Miyasaka has demonstrated that perovskite crystal thinfilms possess eﬃcient light-emitting properties, a phenomenon derived from this unique physical characteristic (Chemistry Letters, Chemical Society of Japan, 2012). By early 2018, theconversion eﬃciency of perovskite-based solar cells had surpassed those of compound semiconductor solar cells, such as Cu-In-Ga-Se (CIGS) and CdTe, achieving eﬃciencies over 26.0% andmatching the market-leading crystalline silicon cells.
Dr. Miyasaka’s key research achievements include:
I. During the solution-coating process to form a photovoltaic layer of perovskite polycrys-16talline thin film, he explored crystallization conditions to enhance crystal quality. This led to afilm-forming method in an ambient humid atmosphere, increasing conversion eﬃciency to over
20% (Paper. No. 15).
II. He developed a defect passivation technology that protects carrier transfers against interfacial defects by forming a self-assembled organic molecule layer at the interface. This approachachieved nearly 23% eﬃciency and a voltage output approaching the theoretical limit (Paper. No.
3).
III. The focus on eﬃciency enhancement extended to all-inorganic perovskite compositions
with high thermal stability. A cell using CsPbI2 Br as perovskite, modified at the interface tominimize energy loss, achieved a high voltage of over 1.4 V. This cell demonstrated an eﬃciency
exceeding 34% under low-intensity indoor lighting (Paper. No. 8).
IV. In collaboration with JAXA, Dr. Miyasaka has initiated research on the space applications of perovskite solar cells, revealing their high durability against high-energy radiation (electron and proton beams) in the space environment (Paper. No. 16). This finding has prompted
numerous research institutes worldwide to validate its reproducibility.
In 2012, following the achievement of perovskite solar cells surpassing 10% eﬃciency,
Peccell Technologies, Inc., a university venture company founded by Dr. Miyasaka in 2004,
filed for 12 patents, setting a precedent in the field. Most of these patents have been granted.
Halide perovskite crystals oﬀer several industrial advantages over silicon and other semiconductor materials used in solar cells, not only in terms of high conversion eﬃciency but also invarious other aspects. These advantages have attracted numerous companies, both in Japan andinternationally, towards the commercialization of perovskite-based technologies:(1) The solution coating (printing) method used for film formation is a low-cost and highspeed process. The synthetic raw materials, including lead and iodine, are inexpensive and can besourced domestically. The cost of perovskite semiconductor film is approximately 200 JPY/m2 ,which is about 1/20 that of silicon.
(2) Since the process does not require high temperatures (below 120℃), perovskite photovoltaic films can be deposited on plastic substrates, facilitating the creation of lightweight andflexible devices.
(3) With a high optical absorption coeﬃcient (105 /cm), the absorber functions eﬀectively
with thicknesses less than 1 µm, significantly thinner than crystalline silicon absorbers, enabling
the production of thin and highly flexible devices.
(4) The bandgap energy of perovskites is tunable by altering the halogen composition, allowing for the adjustment of edge wavelengths. This property is crucial for developing multi-junction
tandem cells that require wavelength optimization.
(5) The optical transparency of perovskite films enables the creation of semi-transparent
solar cells, paving the way for bifacial power generation devices that absorb light from bothsides.
(6) The defect tolerance of perovskite semiconductors ensures high conversion eﬃciency
even under weak light conditions. This capability allows for power generation not only outdoors
on sunny days but also on cloudy or rainy days, and even under indoor lighting.

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Dr. Miyasaka has shown that a key factor in enhancing the eﬃciency of solar cells is thesolution-based crystallization process, which improves the quality of perovskite polycrystalline
films. Optimizing particle size and achieving a dense, flat crystalline film with minimal physical defects can significantly reduce structural defects and increase eﬃciency. Japan’s industrial sector possesses strong technological capabilities in this chemical process. Therefore, Dr.
Miyasaka’s pioneering work in the field of perovskite solar cells is expected to significantly contribute to the realization of a carbon-neutral society and is deserving of the Japan Academy Prize.

List of Main Publications(1) “Halide perovskite for indoor photovoltaics: The next possibility”, Z. Guo, A. K. Jena, andT. Miyasaka. ACS Energy Lett., 8, 90–95 (2023).
(2) “A semitransparent silver-bismuth iodide solar cell with Voc above 0.8 V for indoor photovoltaics”, N. B. C. Guerrero, Z. Guo, N. Shibayama, A. K. Jena, and T. Miyasaka. ACS
Appl. Energy Mater., 6, 10274–10284 (2023).
(3) “Phenethylamine-based interfacial dipole engineering for high Voc triple-cation perovskite
solar cells”, G. M. Kim, H. Sato, Y. Ohkura, A. Ishii, and T. Miyasaka. Adv. Energy Mat.,12, 2102856 (2022).
(4) “FAPbBr3 perovskite solar cells with VOC over 1.5 V by controlled crystal growth using atetramethylenesulfoxide”, Y. Numata, N. Shibayama, and T. Miyasaka. J. Mater. Chem. A,
10, 672–681 (2022).
(5) “The high open-circuit voltage of perovskite solar cells: a review”, Z. Guo, A. K. Jena, G.
M. Kim, and T. Miyasaka. Energy Environ. Sci.,15, 3171–3222 (2022).
(6) “Dopant-free polymer HTM-based CsPbI2 Br solar cells with eﬃciency over 17% in sunlight and 34% in indoor light”, Z. Guo, A. K. Jena, I. Takei, M. Ikegami, A. Ishii, Y.
Numata, N. Shibayama, and T. Miyasaka. Adv. Functional Mat., 31, 2103614 (2021).
(7) “Artemisinin-passivated mixed-cation perovskite films for durable flexible perovskite solar
cells with over 21% eﬃciency”, L. Yang, Q. Xiong, Y. Li, P. Gao, B. Xu, H. Lin, X. Li and
T. Miyasaka. J. Mater. Chem. A, 9, 1574–1582 (2021).
(8) “VOC over 1.4 V for amorphous tin-oxide-based dopant-free CsPbI2 Br perovskite solar
cells”, Z. Guo, A. K. Jena, I. Takei, G. M. Kim, M. A. Kamarudin, Y. Sanehira, A. Ishii, Y.
Numata, S. Hayase, and T. Miyasaka. J. Am. Chem. Soc., 142, 9725–9734 (2020).
(9) “MACl–assisted Ge doping of Pb–Hybrid perovskite: A universal route to stabilize highperovskite solar cells”, G. M. Kim, A. Ishii, and T. Miyasaka. Adv. Energy Mat., 1903299(2020).
(10) “Lead(II) propionate additive and a dopant-free polymer hole transport material for
CsPbI2 Br perovskite solar cells”, S. Oez, A. K. Jena, A. Kulkarni, K. Mouri, T. Yokoyama,
I. Takei, F. Uenlue, S. Mathur, and T. Miyasaka. ACS Energy Lett., 5, 1292–1299 (2020).
(11) “Femto- to microsecond dynamics of excited electrons in a quadruple cation perovskite”, E.
Jung, K. Budzinauskas, S. Oez, F. Uenlue, H. Kuhn, J. Wagner, D. Grabowski, B. Klingebiel, M. Cherasse, J. Dong, P. Aversa, P. Vivo, T. Kirchartz, and T. Miyasaka, P. H. M. van
Loosdrecht, L. Perfetti, and S. Mathur. ACS Energy Lett., 5, 785–792 (2020).

18(12) “Halide perovskite photovoltaics: background, status, and future prospects”, A. K. Jena, A.
Kulkarni, and T. Miyasaka. Chem. Rev., 119, 3036–3103 (2019).
(13) “Perovskite solar cells: Can we go organic-free, lead-free, and dopant-free?”, T. Miyasaka,
A. Kulkarni, G. M. Kim, S. Oez, and A. K. Jena. Adv. Energy Mat., 1902500 (2019).
(14) “Performance enhancement of AgBi2 I7 solar cells by modulating a solvent-mediated adductand tuning remnant BiI3 in one-step crystallization”, A. Kulkarni, A. K. Jena, M. Ikegami,
and T. Miyasaka. Chem. Comm., 55, 4031–4034 (2019).
(15) “Stabilizing the eﬃciency beyond 20% with a mixed cation perovskite solar cell fabricatedin ambient air under controlled humidity”, T. Singh, and T. Miyasaka. Adv. Energy Mat., 8,1700677 (2018).
(16) “Tolerance of perovskite solar cell to high-energy particle irradiations in space environment”, Y. Miyazawa, M. Ikegami, H.-W. Chen, T. Ohshima, M. Imaizumi, K. Hirose, andT. Miyasaka. iScience, 2, 148–155 (2018).
(17) “Ambient fabrication of 126 µm thick complete perovskite photovoltaic device for highflexibility and performance”, T. Singh, M. Ikegami, and T. Miyasaka. ACS Appl. Energy
Mater., 1, 6741–6747 (2018).
(18) “Microstructural analysis and optical properties of the halide double perovskite Cs2 BiAgBr6
single crystals”, O.A. Lozhkina, A.A. Murashkina, M.S. Elizarov, V.V. Shilovskikh, A.A.
Zolotarev, Yu.V. Kapitonov, R. Kevorkyants, A.V. Emeline, and T. Miyasaka. Chem. Phys.
Lett., 18–22 (2018).
(19) “Sulfate-assisted interfacial engineering for high yield and eﬃciency of triple cation perovskite solar cells with alkali-doped TiO2 electron-transporting layers”, T. Singh, S. Oz, A.
Sasinska, R. Frohnhoven, S. Mathur, and T. Miyasaka. Adv. Funct. Mater, 1706287 (2018).
(20) “Highly eﬃcient and stable low-temperature processed ZnO solar cells with triple cation
perovskite absorber”, J. Song, L. Liu, X.-F. Wang, G. Chen, W. Tian, and T. Miyasaka. J.
Mater. Chem. A, 5, 13439–13447 (2017).
(21) “Controlled crystal grain growth in mixed cation-halide perovskite by evaporated solvent
vapor recycling method for high eﬃciency solar cells”, Y. Numata, A. Kogo, Y. Udagawa,
H. Kunugita, K. Ema, Y. Sanehira, and T. Miyasaka. ACS Appl. Mater. Interfaces, 9,18739–18747 (2017).
(22) “Poly(4-Vinylpyridine)-based interfacial passivation to enhance voltage and moisture stability of lead halide perovskite solar cells”, B. Chaudhary, A. Kulkarni, A. K. Jena, M.
Ikegami, Y. Udagawa, H. Kunugita, K. Ema, and T. Miyasaka. ChemSusChem, 10, 2473–
2479 (2017).
(23) “Towards stable and commercially available perovskite solar cells”, N. G. Park, M. Grätzel,
T. Miyasaka, K. Zhu, and K. Emery. Nature Energy, 1, 16152 (2016).
(24) “Eﬀect of electron transporting layer on bismuth-based lead-free perovskite (CH3 NH3 )3
Bi2 I9 for Photovoltaic Applications”, T. Singh, A. Kulkarni, M. Ikegami, and T. Miyasaka.
ACS Appl. Mater. Interfaces, 8, 14542–14547 (2016).
(25) “Low-temperature-processed ZnO-SnO2 nanocomposite for eﬃcient planar perovskite solar
cells”, J. Song, E. Zheng, X.-F. Wang, W. Tian and T. Miyasaka. Solar Energy Mater. Solar
Cells, 144, 623–630 (2016).

19(26) “High performance perovskite solar cell via multi-cycle low temperature processing of lead
acetate precursor solutions”, T. Singh, and T. Miyasaka. Chem. Commun., 52, 4784–4787(2016).
(27) “Steady state performance, photo-induced performance degradation and their relation totransient hysteresis in perovskite solar cells”, A. K. Jena, A. Kulkarni, M. Ikegami, and T.
Miyasaka. J. Power Sources, 309, 1–10 (2016).
(28) “Low-temperature SnO2 -based electron selective contact for eﬃcient and stable perovskite
solar cells”, J. Song, E. Zheng, J. Bian, X. F. Wang, W. Tian, Y. Sanehira, and T. Miyasaka.
J. Mater. Chem. A, 3, 10837–10844 (2015).
(29) “Perovskite photovoltaics: Rare functions of organo lead halide in solar cells and optoelectronic devices”, T. Miyasaka. Chem. Lett., 44, 720–729 (2015).
(30) “The interface between FTO and the TiO2 compact layer can be one of the origins to hysteresis in planar heterojunction perovskite solar cells”, A. K. Jena, H.-W. Chen, A. Kogo,
Y. Sanehira, M. Ikegami, T. Miyasaka. ACS Appl. Mater. Interfaces, 7, 9817–9823 (2015).
(31) “Excitonic feature in hybrid perovskite CH3 NH3 PbBr3 single crystals”, H. Kunugita, T.
Hashimoto, Y. Kiyota, Y. Udagawa, Y. Takeoka, Y. Nakamura, J. Sano, T. Matsushita,
T.Kondo, and T. Miyasaka, K. Ema. Chem. Lett., 44, 852–854 (2015).
(32) “Eﬃcient perovskite solar cell fabricated using an aqueous lead nitrate precursor”, T.-Yu
Hsieh, T. C. Wei, K.-L. Wu, M. Ikegami, and T. Miyasaka. Chem. Commun., 51, 13294–
13297 (2015).
(33) “Eﬃcient and environmentally stable perovskite solar cells based on ZnO electron collection layer”, J. Song, J. Bian, E. Zheng, X.-F. Wang, W. Tian, and T. Miyasaka. Chem. Lett.,
44, 610–612 (2015).
(34) “A switchable high-sensitivity photodetecting and photovoltaic device with perovskite absorber”, H.-W. Chen, N. Sakai, A. K. Jena, Y. Sanehira, M. Ikegami, K.-C. Ho, and T.
Miyasaka. J. Phys. Chem. Lett. 6, 1773–1779 (2015).
(35) “Emergence of hysteresis and transient ferroelectric response in organo-lead halide perovskite solar cells”, H. W Chen, N Sakai, M Ikegami, and T Miyasaka. J. Physical Chem.
Lett., 6, 164–169 (2014).
(36) “Fully crystalline perovskite-perylene hybrid photovoltaic cell capable of 1.2 V output witha minimized voltage loss”, A. Ishii, A. K. Jena, and T. Miyasaka. APL Materials, 2, 091102(2014).
(37) “Quantum conversion enhancement with TiOx compact layer for ITO plastic film-based
low-temperature-processed dye-sensitized photoelectrode”, S. Morita, M. Ikegami, T.-C.
Wei, and T. Miyasaka. ChemPhysChem, 15, 1190–1193 (2014).
(38) “Tri-functional Nb2 O5 nano-islands coated on an indium tin oxide layer for a highly eﬃcientdye-sensitized plastic photoanode”, S. Morita, T.-C. Wei, M. Ikegami, and T. Miyasaka. J.
Power Sources, 240, 753–758 (2013).
(39) “Eﬃcient hybrid solar cells based on meso-superstructured organometal halide
perovskites”, M. M. Lee, J. Teuscher, T. Miyasaka, T. N. Murakami, and H. J. Snaith.
Science, 338, 643–647 (2012).
(40) “Highly luminescent lead bromide perovskite nanoparticles synthesized with porous alu-20

mina media”, A. Kojima, M. Ikegami, K. Teshima, and T. Miyasaka. Chem. Lett., 41,
397–399 (2012).
(41) “A high voltage organic-inorganic hybrid photovoltaic cell sensitized with metal-ligand interfacial complexes”, A. Ishii, and T. Miyasaka. Chem. Commun., 48, 9900–9902 (2012).
(42) “Organometal halide perovskites as visible-light sensitizers for photovoltaic cells”, A. Kojima, K. Teshima, Y. Shirai, and T. Miyasaka. J. Am. Chem. Soc., 131, 6050–6051 (2009).
(43) “Low-temperature fabrication of dye-sensitized plastic electrodes by electrophoretic preparation of mesoporous TiO2 layers”, T. Miyasaka, and Y. Kijitori. J. Electrochem. Soc., 151,
A1767–A1773 (2004).
(44) “The photocapacitor: An eﬃcient self-charging capacitor for direct storage of solar energy”,
T. Miyasaka and T. N. Murakami. Appl. Phys. Lett., 85, 3932–3934 (2004).
(45) “Tin-based amorphous oxide. A high-capacity lithium storage material”, Y. Idota, T. Kubota, A. Matsufuji, Y. Maekawa, and T. Miyasaka. Science, 276, 1395–1397 (1997).