Photovoltaic laser power converters producing 21 W/cm2 at a conversion efficiency of 66.5%

Most efficient photovoltaic laser power converters (PVLPCs) are approaching efficiencies of 70% but produce power densities of only a few W/cm2, which precludes their implementation in high-power applications. In the pursuit of higher output power densities, here we revisit the PVLPC design guidelines and propose triple-junction (3J) GaAs devices optimized for 840-860 nm laser light. We incorporate rear heterojunction (RHJ) structures for both the top and middle subcells combined with a front homojunction (FJ) structure for the bottom subcell. This design enables the achievement of an internal radiative efficiency of 90% in the subcells. Following these guidelines, we demonstrate a 3J-PVLPC, which supplies an output power density of 21.3 W/cm2 at a voltage of 3.7 V with a conversion efficiency of 66.5% G 1.7% at 25 degrees C. Simulations indicate that this 3JPVLPC could supply a power density of 65 W/cm2 while maintaining an efficiency of 65% when using a higher-power laser providing 100 W/cm2, enabling the implementation of 1 kW receiver modules with compact areas below 4 3 4 cm2. This result demonstrates the feasibility of the kilowatt power-by-light technology in both terrestrial and space applications.