Prominent texturing and enhanced thermoelectric performance of misfit layered (PbS)1.18(TiS2)2 via an exfoliation-restacking approach

Abstract

Micro-texturing engineering has been taken to manipulate the thermoelectric performance of (PbS)1.18(TiS2)2 via an exfoliation-restacking approach coupled with spark plasma sintering. The resultant polycrystalline material showed remarkably promoted (00l) texturing together with a noticeable reduction in grain size, leading to prominently prior transport properties along the in-plane direction. Particularly, the electrical conductivity was much improved due to the increased carrier mobility without affecting carrier concentration and DOS effective mass, which gave rise to a maintained Seebeck coefficient and consequently a high power factor of 8.8–11.4 μW·cm−1·K−2 in the range of 323 – 773 K. Despite the slightly increased thermal conductivity due to electronic component and the limited suppression of phonon transport, a record-high ZT value of 0.52 has been achieved with an increase by ∼20% compared to that of the pristine one, demonstrating the significant effectiveness of exfoliation-restacking on boosting the thermoelectric performance for misfit layered materials.