Laser Direct Writing of Graphitic Carbon with Process-Tunable p- and n-Type Thermoelectric Response

Thermoelectric power generation, which directly converts temperature differences in the environment into electrical energy, has attracted considerable attention as a next-generation power supply technology because of its maintenance-free operation. Laser-induced graphitization has been investigated as a fabrication method for thermoelectric generators because carbon-based materials are readily available and offer lower environmental impact, and the maskless direct-writing process enables simple fabrication with high design flexibility. However, graphitic carbon structures formed by laser-induced graphitization generally exhibit p-type thermoelectric response, which was associated with absorption of atmospheric species such as O 2 and H 2 O. In this study, graphitic carbon structures exhibiting process-tunable p- and n-type thermoelectric response are fabricated by laser irradiation using polyimide as a precursor and aniline as a nitrogen source. Moreover, as a proof-of-concept, thermoelectric generators composed of these structures are fabricated, and power generation is demonstrated using the fabricated generators. The proposed method provides an approach for further enhancing the output of thermoelectric generators fabricated by laser-induced graphitization.