Research Units

Ferroelectric Photovoltaics

Ferroelectric materials exhibit a characteristic photovoltaic effect that can generate photovoltage far exceeding their bandgap energy. The absence of limitation in the photovoltage by the bandgap is a great advantage of the ferroelectric photovoltaic (FPV) effect over the conventional PV effect in p-n junctions of semiconductors. Since typical ferroelectric oxides have the wide bandgap, a vanishingly small photoresponse under visible light has been an issue to be overcome. To activate the photoresponse under visible-light irradiation, Matsuo and Noguchi have proposed a materials design strategy ‘gap-state’ engineering, in which defect states within the bandgap derived from intentionally introduced impurities act as a stepping stone for photocarrier generation. The aim of this research unit is to clarify the photovoltaic properties and photocarrier dynamics in transition metal-doped ferroelectrics with the gap states. In this collaboration research, Ceracomp Co., Ltd. supplies ferroelectric single crystals synthesized by a solid-state single crystal growth (SSCG) method and their FPV properties are evaluated in Kumamoto university. The SSCG method is a cost-effective crystal growth method that enables the fabrication of single crystals with complex chemical compositions which are difficult to obtain in conventional melt-growth techniques. By combining the gap-state engineering and the SSCG method, we will develop novel ferroelectric materials that exhibit enhanced FPV response under visible light irradiation.

Ferroelectric Photovoltaics

Unit members

  • Japan
    Unit Coordinator
    Hiroki MATSUO Website
    Associate Professor, IROAST, Kumamoto University
  • Japan
    Yuji NOGUCHI Website
    Professor, Research and Education Institute for Semiconductors and Informatics, Kumamoto University
  • Korea
    Ho-Yong LEE
    Professor/President, Ceracomp Co., Ltd.
  • Korea
    Moon-Chan KIM
    Researcher,Ceracomp Co., Ltd





  • (Invited) Hiroki Matsuo, Yuji Noguchi “Activation of Visible Light Response in Ferroelectric Photovoltaic Effects via Gap-State Engineering”
    The Joint International Conference on Applied Physics and Materials Applications & Applied Magnetism and Ferroelectrics (ICAPMA-JAMG-2021), December 2021, Pattaya (Virtual)
  • Hiroki Matsuo, Yuji Noguchi “Gap-State Engineering for Enhanced Ferroelectric Photovoltaic Effect under Visible Light Irradiation”
    2021 MRS Fall Meeting & Exhibit, December 2021, Boston (Virtual)
  • Hiroki Matsuo, Yuji Noguchi “Photovoltaic properties of BiFeO3-based ferroelectric thin film via gap-state engineering”
    The 50 th Japan Conference on Crystal Growth, October 2021, Virtual.
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