67.5% Efficient InP-Based Laser Power Converters at 1470 nm at 77 K.

Recent developments in long wavelength and cryogenic laser power converters have unlocked record performances in both areas. Here, devices for an optical input at ~1470 nm are studied for cryogenic applications, combining these cryogenic and long-wavelength attributes. Multijunction laser power converters are demonstrated to have a high-efficiency operation at 77 K. The photovoltaic-power-converting III-V semiconductor devices are designed with InGaAs-absorbing layers, here with 10 thin subcells (PT10), connected by transparent tunnel junctions. Unprecedented conversion efficiencies of up to 67.5% are measured at liquid nitrogen temperatures with an output power of P_mpp = 1.35 W at an average optical input intensity of ~62 W/cm². A remarkably low bandgap voltage offset value of W_oc~50 mV is obtained at an average optical input intensity of ~31 W/cm². [ABSTRACT FROM AUTHOR]