PEAK Staff Profile

Yoshitaka Okada, BSc (U. London), MEng, PhD (U. Tokyo)
Professor – Environmental Sciences

Contact: okada[at]


Prof. Okada Prof. Yoshitaka Okada is Professor at the Research Center for Advanced Science and Technology (RCAST) and Graduate School of Engineering of the University of Tokyo. He received his BSc (1st Class Honours) in electronic and electrical engineering from King’s College of the University of London in 1984, and MEng and PhD degrees in electronic engineering from the University of Tokyo in 1987 and 1990. He was appointed as Visiting Assistant Professor in the Department of Electrical Engineering, Stanford University in 1995-96, Visiting Fellow in the Department of Physics, Imperial College London in 2006, and Visiting Fellow of Clare Hall and Cavendish Laboratory of the University of Cambridge in 2015. He has coauthored over 230 journal papers, 195 international conference presentations, and 38 book chapters and scientific articles. He is a Fellow of the Japan Society of Applied Physics for his contribution to the field of innovative high-efficiency quantum nanostructure solar cells and materials.

Research Interests

His recent research interests include thin-film growth of low-dimensional III-V quantum nanostructures by molecular beam epitaxy (MBE) technique for applications to advanced high-efficiency photovoltaics such as multijunction, intermediate-band and hot-carrier solar cells. He also performs outdoor characterization of solar cell modules in solar-thermal hybrid power generation system.

Selected Publications

  1. Y. Okada, T. Morioka, K. Yoshida, R. Oshima, Y. Shoji, T. Inoue, and T. Kita, “Increase of photocurrent by optical transitions via intermediate quantum states in direct-doped InAs/GaNAs strain-compensated quantum dot solar cell”, Journal of Applied Physics, 109, 024301 (2011).
  2. T. Sogabe, Y. Shoji, M. Ohba, K. Yoshida, R. Tamaki, H-F. Hong, C-H. Wu, C-T. Kuo, S. Tomić, and Y. Okada, “Intermediate-band dynamics of quantum dots solar cell in concentrator photovoltaic modules”, Scientific Reports, 4, 4792 (2014).
  3. A. Datas, E. Lopez, I. Ramiro, E. Antolin, A. Marti, A. Luque, R. Tamaki, Y. Shoji, T. Sogabe, and Y. Okada, “Intermediate Band Solar Cell with Extreme Broadband Spectrum Quantum Efficiency”, Physical Review Letters, 114, 157701 (2015).
  4. Y. Okada, N. J. Ekins-Daukes, T. Kita, R. Tamaki, M. Yoshida, A. Pusch, O. Hess, C. C. Phillips, D. J. Farrell, K. Yoshida, N. Ahsan, Y. Shoji, T. Sogabe, and J-F. Guillemoles, “Intermediate band solar cells: Recent progress and future directions”, Applied Physics Reviews, 2, 021302 (2015).
  5. T. Sogabe, C-Y. Hung, R. Tamaki, S. Tomić, K. Yamaguchi, N. Ekins-Daukes, and Y. Okada, “Experimental demonstration of energy-transfer ratchet intermediate-band solar cell”, Communications Physics, 4, 38 (2021).