Near-Field Thermophotovoltaic Conversion with High Electrical Power Density and Cell Efficiency above 14

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Near-field thermal radiation offers significant energy potential for harvesting and material characterization.
• Despite theoretical predictions, efficient experimental near-field thermophotovoltaic conversion has remained elusive.
• Nanoengineered devices have been explored for two decades to harness near-field thermal photons.

Purpose of the Study:

• To experimentally demonstrate efficient near-field thermophotovoltaic conversion.
• To achieve unprecedented electrical power density outputs from near-field thermal energy.
• To validate the potential of near-field thermophotovoltaic converters.

Main Methods:

• Utilized a micrometer-sized indium antimonide (InSb) photovoltaic cell cooled to 77 K.
• Employed a graphite microsphere emitter heated to approximately 730 K.
• Positioned the photovoltaic cell at nanometer distances from the emitter to capture near-field thermal photons.

Main Results:

• Achieved a near-field power conversion efficiency exceeding 14% for the photovoltaic cell.
• Demonstrated electrical power density outputs of 0.75 W cm^-2, significantly higher than previous attempts.
• Confirmed the viability of near-field thermophotovoltaic conversion as a competitive energy harvesting technology.

Conclusions:

• Near-field thermophotovoltaic converters now rival other thermal-to-electrical conversion devices.
• The study paves the way for efficient photoelectric detection of near-field thermal photons.
• This work opens new avenues for advanced energy harvesting and sensing applications.