Low Bandgap InAs-Based Thermophotovoltaic Cells for Heat-Electricity Conversion

The practical realization of thermophotovoltaic (TPV) cells, which can directly convert heat into electric power, is of considerable technological interest. However, most existing TPV cells require heat sources at temperatures of ∼1800°C. Here we report a low bandgap mid-infrared cell based on InAs and demonstrate TPV operation with heat sources at temperatures in the range 500–950°C. The maximum open circuit voltage (Voc) and short circuit current density (Jsc) were measured as 0.06 V and 0.89 A cm−2 for a blackbody temperature of 950°C and an incident power density of 720 mW cm−2 without antireflection coating or electrode optimisation. TPV operation was obtained with heat sources at temperatures as low as 500°C, which represents progress towards energy scavenging and waste heat recovery applications.