Far-field thermophotovoltaics improved by reducing separation between emitter and photovoltaic cell to the nanoscale
https://www.army.mil/article/249779/turning_thermal_energy_into_electricity_could_help_soldiers "achieved a record ~5 kW/m2 power output, which is an order of magnitude larger than systems previously reported" Related: Researchers develop new selective emitter based on iridium for thermophotovoltaics https://phys.org/news/2023-09-emitter-based-iridium-thermophotovoltaics.html