Giant bulk photovoltaic effect in solar cell architectures with ultra-wide bandgap Ga2O3 transparent conducting electrodes

• Published in: Materials today energy Vol. 14; p. 100350
• Main Authors: Pérez-Tomás, A., Chikoidze, E., Dumont, Y., Jennings, M.R., Russell, S.O., Vales-Castro, P., Catalan, G., Lira-Cantú, M., Ton –That, C., Teherani, F.H., Sandana, V.E., Bove, P., Rogers, D.J.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2019
• Subjects: Bulk photovoltaic effect; Ferroelectric photovoltaics; Ga2O3; Gallium oxide; Pb(Zr,Ti)O3; Physics; Solar cell architecture; Transparent conducting oxide; Ultra-wide bandgap semiconductors; Solar cell architecture; Pb(Zr,Ti)O3; Ultra-wide bandgap semiconductors; Gallium oxide; Bulk photovoltaic effect; Ferroelectric photovoltaics; Ga2O3; Transparent conducting oxide
• ISSN: 2468-6069; 2468-6069
• DOI: 10.1016/j.mtener.2019.100350

The use of ultra-wide bandgap transparent conducting beta gallium oxide (β-Ga2O3) thin films as electrodes in ferroelectric solar cells is reported. In a new material structure for energy applications, we report a solar cell structure (a light absorber sandwiched in between two electrodes - one of them - transparent) which is not constrained by the Shockley–Queisser limit for open-circuit voltage (Voc) under typical indoor light. The solar blindness of the electrode enables a record-breaking bulk photovoltaic effect (BPE) with white light illumination (general use indoor light). This work opens up the perspective of ferroelectric photovoltaics which are not subject to the Shockley-Queisser limit by bringing into scene solar-blind conducting oxides. •Here, we use the ultra-wide bandgap semiconductor Ga2O3 for the first time in a solar cell as a transparent superstrate electrode•We show that its ultra-wide bandgap resolves a long-standing problem for ferroelectric photovoltaic devices.•The ultra-wide bandgap of Ga2O3 (~5 eV) inherently avoids the problem of undesirable photo-carrier injection that afflicts all other currently available transparent conductors.•Adoption of the solar blind transparent conductor has resulted in a record-breaking white-light-induced photoelectric field (0.7 MV/cm).