Morphology-manipulated topological insulator Bi2Se3 nanosheets for integrated microwave absorption and thermoelectric conversion
The proliferation of high-frequency communication technologies has escalated electromagnetic (EM) pollution, posing risks to health and device reliability. Conventional microwave absorbers dissipate EM energy as heat, creating thermal management burdens and energy waste. This study introduces Bi2Se3 nanosheets, a topological insulator with surface conductivity and internal insulation, as a dual-functional material capable of both microwave absorption and thermoelectric conversion. Nanosheets with controlled morphology were synthesized via a polyol reduction method, with thickness and lateral size tuned by preparation conditions. The resulting composites exhibited excellent microwave absorption, achieving a broad absorption bandwidth of 2.95 GHz at sub-millimeter thickness. A multilayered structure design enabled full-band absorption from 2 to 18 GHz using a single absorbent. The Seebeck coefficient, derived from temperature differences up to 110 °C, was -152 μV/K, indicating efficient conversion of absorbed EM energy into electrical energy. This work demonstrates the potential of Bi2Se3 nanomaterials for self-powered electromagnetic devices, addressing both EM pollution and energy supply challenges.