Ce-filled Ni_1.5Co_2.5Sb₁₂ Skutterudite Thin Films with Record-High Figure of Merit And Device Performance

Realizing high thermoelectric performance in CoSb₃ skutterudite-based thin films and their devices is historically challenging, especially due to the lack of high-performing thin-film-based device working at medium-to-high temperatures. Here, a record-high ZT of 1.1 is achieved at 683 K in an n-type Ce_0.3Ni_1.5Co_2.5Sb₁₂ thin film, fabricated from a self-designed target via advanced pulsed laser deposition. Both experimental and computational results confirm that the Ce-filling and metal-featured nanoinclusions such as CeSb contribute to high electrical conductivity, while the Ni-doping and significantly strengthen the energy filtering effect that occurs at the dense interfaces between the Ce_0.3Ni_1.5Co_2.5Sb₁₂ matrix and the nanoinclusions which leads to a large Seebeck coefficient, giving rise to such a high ZT. In addition, a new-type CoSb₃ thin-film-based device is successfully fabricated, which exhibits a high output power density of 8.25 mW cm⁻² at a temperature difference of 140 K and a cold-side temperature of 573 K, indicating the potential for application to medium-to-high-temperature power generation scenarios.