In 2024, researchers announced a device that achieved 44% efficiency, The cell used silicon carbide as the heat-storage material. SiC was enveloped a semiconductor material made of indium, gallium and arsenic. At 1,435 °C (2,615 °F) the device radiates thermal photons at various energy levels. The semiconductor captures 20 to 30% of the photons. Additional layers include air and a gold reflector layer.