Near-field thermophotovoltaic energy conversion using an intermediate transparent substrate

Area of Science:

• Energy Conversion
• Nanophotonics
• Materials Science

Background:

• Near-field thermophotovoltaic (TPV) systems offer potential for efficient energy conversion.
• Optimizing thermal emission and minimizing parasitic heat transfer are critical challenges in TPV systems.
• Surface modes on photovoltaic (PV) cells can lead to unwanted heat transfer, reducing efficiency.

Purpose of the Study:

• To propose and validate a novel scheme for near-field TPV energy conversion.
• To enhance interband absorption while suppressing unwanted heat transfer in TPV systems.
• To demonstrate the applicability of the proposed scheme with common emitter materials like silicon (Si) and tungsten (W).

Main Methods:

• Utilizing an intermediate transparent substrate between the thermal emitter and the PV cell.
• Employing a one-dimensional Si photonic crystal as a thermal emitter.
• Designing a system with an InGaAs PV cell and an intermediate Si substrate.

Main Results:

• The intermediate substrate effectively suppresses heat transfer via surface modes.
• The proposed scheme maintains enhanced interband absorption.
• Achieved high power density (>5 × 10^4 W/m^2) and power conversion efficiency (>40%) at a 50-nm gap.
• Demonstrated applicability for both Si and W emitters.

Conclusions:

• The proposed intermediate substrate scheme is effective for near-field TPV energy conversion.
• This approach significantly improves both power density and efficiency in TPV systems.
• The design is versatile and applicable to various emitter materials and PV cells.