Tandem-structured, hot electron based photovoltaic cell with double Schottky barriers

Area of Science:

• Materials Science
• Nanotechnology
• Renewable Energy

Background:

• Hot electron based photovoltaic cells offer a promising route for enhanced solar energy conversion.
• Metal/semiconductor nanodiodes are key components in photovoltaic devices, but their efficiency can be limited.
• Tandem structures and Schottky barriers are explored to improve charge carrier harvesting.

Purpose of the Study:

• To demonstrate a tandem-structured photovoltaic cell utilizing hot electrons and double Schottky barriers.
• To investigate the effect of double Schottky barriers on hot electron harvesting and photocurrent enhancement.
• To improve light absorption and overall solar energy conversion efficiency.

Main Methods:

• Fabrication of tandem cells using TiO2/Au/Si and TiO2/Au/TiO2 structures.
• Utilizing double Schottky barriers at metal/semiconductor interfaces.
• Characterization of photocurrent enhancement and efficiency improvements.

Main Results:

• Photocurrent enhancement was detected in the fabricated tandem cells.
• The double Schottky barriers provided an additional pathway for harvesting hot electrons, amplified by multiple reflections.
• Light absorption was improved due to band-to-band excitation in semiconductors with different band gaps.
• The tandem-structured TiO2/Au/Si cell showed an 86% increase in short-circuit current and a 70% increase in energy conversion efficiency compared to Au/Si nanodiodes.
• An overall solar energy conversion efficiency of 5.3% was achieved.

Conclusions:

• The developed tandem-structured, hot electron based photovoltaic cell with double Schottky barriers effectively enhances hot electron harvesting.
• This innovative design leads to significant improvements in photocurrent and solar energy conversion efficiency.
• The findings pave the way for more efficient next-generation solar cell technologies.