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A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy
Published on: April 8, 2018
Efficient photovoltaic current generation at ferroelectric domain walls
Jan Seidel1, Deyi Fu, Seung-Yeul Yang
1Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA.
Physical Review Letters
|October 27, 2011
Summary
Domain walls in ferroelectric materials generate photovoltaic current under illumination. This novel photovoltaic effect, observed in bismuth ferrite (BiFeO3), offers high efficiency and potential for new solar energy technologies.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Renewable Energy
Background:
- Ferroelectric materials possess spontaneous electric polarization.
- Periodic domain structures are common in ferroelectrics.
- Photovoltaic effects are crucial for solar energy conversion.
Purpose of the Study:
- To elucidate the mechanism of a newly observed photovoltaic effect in ferroelectrics with periodic domain structures.
- To investigate the role of domain walls in photovoltaic current generation.
- To explore the potential for generating large photovoltages and high internal quantum efficiencies.
Main Methods:
- Observation of photovoltaic effect in bismuth ferrite (BiFeO3) films.
- Analysis of domain wall behavior under illumination.
- Measurement of photovoltage and internal quantum efficiency.
Main Results:
- Domain walls act as nanoscale generators of photovoltaic current under strong illumination.
- Electrostatic potential steps at domain walls accumulate charge carriers, reducing recombination and creating a net diffusion current.
- Additive photovoltages in periodically ordered domain walls can exceed the material's band gap.
- Internal quantum efficiency approaches 10% for above band-gap photons.
Conclusions:
- The observed photovoltaic effect is attributed to the unique properties of domain walls in ferroelectrics.
- This phenomenon is expected in any system exhibiting similar periodic potentials.
- The findings suggest a new pathway for efficient solar energy harvesting using ferroelectric materials.
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