Multilevel Interface Design to Manipulate Electron and Phonon Scattering in Mesoporous Semiconductor Film for Enhanced Thermoelectric Performances

It remains a great challenge to optimize electron and phonon scattering for high thermoelectric performance in semiconductor materials using traditional composition or phase design methods. Herein, we demonstrate an effective strategy using mesoporous structures to address this challenge. The mesoporous Bi 2 Se 3 thin films with uniform pores and a semiconductor framework were prepared by using amphiphilic block copolymers as structure-directing agents, electric field-driven micellar template interfacial self-assembly, and electrochemical deposition. The porosity, pore size, and thickness can be controlled through tuning parameters such as deposition potential, deposition time, molecular weight of block copolymer, and solution concentration. The resultant multilevel interfacial structures optimized the electron scattering potential and effectively scatter the phonons. This leads to improved Seebeck coefficient and power factor by 268.8% and 730.5% simultaneously, when compared with nonporous samples. The highest power factor can reach 22.36 µW·cm −1 ·K −2 that is higher than most reported values. Furthermore, this novel preparation method has succeeded in other thermoelectric semiconductors such as Bi 2 Te 0.5 Se 2.5 and Cu 3 Se 2 . Therefore, this work provides new insights into the design of novel mesoporous semiconductor thin films as high-performance thermoelectric materials for thermal management in computer chips and other applications.