Advancing silicon thermophotovoltaics by scaling air-bridge technology

Silicon-based thermophotovoltaic (TPV) cells offer a promising pathway for clean energy generation leveraging silicon’s abundance, cost-effectiveness, and well-established fabrication processes. Our group has previously demonstrated small area lateral p-n junction Si TPV cells achieving high power conversion efficiency (PCE) = 19% at 1988K employing the air-bridge back surface reflector (BSR) which enables significantly higher out-of-band reflectance (~98%) compared to conventional Au BSR (~95.3%). In this work, we present the successful fabrication and performance characterization of a large-scale Si TPV module integrating the air-bridge BSR. Our module consists of 40 interconnected Si TPV cells (arranged in a 4 × 10 configuration) fabricated on a single 4-inch wafer. We achieve open circuit voltage (V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OC</inf>) = 4.9 V, short circuit current (ISC) = 0.33 A, fill factor (FF) = 51% and power output (P<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</inf>) = 820 mW at an emitter temperature of 2400°C, confirming the robust performance of air-bridge Si TPV technology at scale. Our results mark a significant step towards the commercialization of Si TPV systems by validating their scalability.