Two-dimensional layered architecture constructing energy and phonon blocks for enhancing thermoelectric performance of InSb

InSb is a narrow-bandgap semiconductor with a zinc blende structure and has been wildly applied in photodetectors, infrared thermal imaging, and Hall devices. The facts of decent band structure, ultrahigh electron mobility, and nontoxic nature indicate that InSb may be a potential mid-temperature thermoelectric material. The critical challenges of InSb, such as high thermal conductivity and small Seebeck coefficient, have induced its ultrahigh lattice thermal conductivity, and thus low ZT values. In view of this, we have developed a competitive strategy typified by the cost-efficient nanocompositing of z wt% QSe(2) (Q = Sn, W). Specifically, the Q(In)(+) and Se-Sb(+) point defects were introduced in the InSb system by nanocompositing the vested two-dimensional layered QSe(2). In addition, the enlarged valence band maximum of intrinsic WSe2 acted as ladders can scatter a fair number of hole carriers, resulting in the relatively enhanced Seebeck coefficient of high temperature. Moreover, the disorderly distributed nanosheets/particles, and dislocations acting as obstacles can effectively delay the heat flow diffusion, inducing the strong scattering of thermal phonons. Consequently, an enhanced power factor of similar to 33.3 mu W cm(-1) K-2 and ZT value of similar to 0.82 at 733 K have been achieved in the 3% WSe2 sample, companied with the engineering output power density omega(max) similar to 233 mu W cm(-2) and thermoelectric conversion efficiency eta similar to 5.2%. This artificially designed approach indicated by suited nanocompositing can integrate several engineering strategies such as point defects, nanoengineering, and energy filtering into one, providing a reference to optimize the thermoelectric performance of other thermoelectric systems.

Automated summary

InSb is a narrow-bandgap semiconductor widely used in photodetectors, infrared thermal imaging, and Hall devices. However, its high thermal conductivity and small Seebeck coefficient limit its thermoelectric performance. By introducing point defects and nanoengineering through nanocompositing, the power factor and ZT value of InSb can be effectively improved, providing a reference for optimizing the performance of other thermoelectric systems.