Oxygen Vacancy Defect Engineering for Transverse Thermoelectric Enhancement: a Novel Extrinsic Pathway beyond...

Area of Science:

• Materials Science
• Solid State Physics
• Thermoelectrics

Background:

• Efficient transverse thermoelectric (TE) generation relies on intrinsic material properties.
• Extrinsic strategies like defect engineering offer new avenues for TE performance enhancement.

Purpose of the Study:

• Investigate the impact of oxygen vacancies on the anomalous Nernst effect.
• Utilize disordered semiconducting Sr3YCo4O11-δ as a model system to study defect engineering.

Main Methods:

• Synthesized Sr3YCo4O11-δ with varying oxygen vacancy concentrations (δ = 0.02, 0.08, 0.14).
• Measured the anomalous Nernst thermopower (S_ANE) for each sample.
• Analyzed the correlation between oxygen vacancies, Co valency, and structural distortions.

Main Results:

• The highest anomalous Nernst thermopower (S_ANE) was observed at δ = 0.14, a 44% increase compared to δ = 0.02.
• Enhanced S_ANE resulted from increased Co3+/Co4+ mixed valency and Co-O-Co bond angle distortions.
• These factors synergistically boosted entropy-driven charge transport and the anomalous Nernst angle.

Conclusions:

• Oxygen vacancy defect engineering is a potent strategy for enhancing transverse TE performance.
• This approach broadens the spectrum of viable TE materials for diverse engineering applications.
• The study highlights the importance of extrinsic factors in optimizing thermoelectric devices.