Large enhancement of the photovoltaic effect in ferroelectric complex oxides through bandgap reduction
- Author(s)
- Hyunji An, Jun Young Han, Bongjae Kim, Jaesun Song, Sang Yun Jeong, Cesare Franchini, Chung Wung Bark, Sanghan Lee
- Abstract
Tuning the bandgap in ferroelectric complex oxides is a possible route for improving the photovoltaic activity of materials. Here, we report the realization of this effect in epitaxial thin films of the ferroelectric complex oxide Bi3.25La0.75Ti3O12 (BLT) suitably doped by Fe and Co. Our study shows that Co (BLCT) doping and combined Fe, Co (BLFCT) doping lead to a reduction of the bandgap by more than 1 eV compared to undoped BLT, accompanied by a surprisingly more efficient visible light absorption. Both BLCT and BLFCT films can absorb visible light with a wavelength of up to 500 nm while still exhibiting ferroelectricity, whereas undoped BLT only absorbs UV light with a wavelength of less than 350 nm. Correlated with its bandgap reduction, the BLFCT film shows a photocurrent density enhanced by 25 times compared to that of BLT films. Density functional theory calculations indicate that the bandgap contraction is caused by the formation of new energy states below the conduction bands due to intermixed transition metal dopants (Fe, Co) in BLT. This mechanism of tuning the bandgap by simple doping can be applied to other wide-bandgap complex oxides, thereby enabling their use in solar energy conversion or optoelectronic applications.
- Organisation(s)
- Computational Materials Physics
- External organisation(s)
- Gwangju Institute of Science and Technology (GIST), Gachon University
- Journal
- Scientific Reports
- Volume
- 6
- No. of pages
- 7
- ISSN
- 2045-2322
- DOI
- https://doi.org/10.1038/srep28313
- Publication date
- 06-2016
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103009 Solid state physics, 103015 Condensed matter, 103025 Quantum mechanics, 103036 Theoretical physics
- Keywords
- Sustainable Development Goals
- SDG 7 - Affordable and Clean Energy
- Portal url
- https://ucris.univie.ac.at/portal/en/publications/large-enhancement-of-the-photovoltaic-effect-in-ferroelectric-complex-oxides-through-bandgap-reduction(fd863912-c3e5-4729-8156-8d9a2d39e288).html