Semiconductor-based selective emitter with a sharp cutoff for thermophotovoltaic energy conversion

Area of Science:

• Materials Science
• Energy Conversion
• Optoelectronics

Background:

• Semiconductor emitters offer potential for sharp cutoff wavelengths due to intrinsic bandgap properties.
• Selective emitters are crucial for improving thermophotovoltaic (TPV) energy conversion efficiency by matching emitter and cell spectra.

Purpose of the Study:

• To investigate a germanium-wafer-based selective emitter for TPV applications.
• To analyze the spectral selectivity and TPV performance of the developed emitter.

Main Methods:

• Optical simulations were performed to predict spectral emittance.
• A germanium-based selective emitter with antireflection and metal coating was fabricated.
• Indirect measurements were used to confirm spectral emittance.
• Theoretical analysis of TPV efficiency was conducted by pairing the emitter with a GaSb cell.

Main Results:

• Optical simulations predicted high spectral emittance (>0.9) between 1-1.85 µm and low sub-bandgap emittance (<0.2).
• A sharp cutoff wavelength around the bandgap was observed, indicating superior spectral selectivity.
• Fabricated emitter's spectral emittance showed excellent agreement with simulation predictions.
• Theoretical analysis indicated potential for enhanced TPV efficiency when paired with a GaSb cell.

Conclusions:

• Germanium-based selective emitters exhibit excellent spectral selectivity for TPV applications.
• The fabricated device performance aligns with simulation predictions.
• This work paves the way for developing advanced semiconductor selective emitters to boost TPV system performance.