Enhancing Thermoelectric Properties of 2D Bi₂Se₃ by 1D Texturing with Graphene

Abstract

Two-dimensional (2D) thermoelectrics have shown enhanced performance compared to bulk thermoelectrics but cannot easily be improved through nanostructuring, since phonon-boundary-scattering becomes ineffective under confined dimensions. To overcome this issue, we introduce a one-dimensional (1D) texturing approach that efficiently suppresses phonon transport between grains of 2D thermoelectrics (TE). Uniaxial graphene wrinkles were utilized to separate high-quality, ultrathin Bi2Se3 films in a highly directional manner. The TE properties of these textured samples exhibit a strongly anisotropic characteristic with a maximum ZT of 1.03 at room temperature, which represents the highest reported value for Bi2Se3. The texturing approach provides a route for the enhancement of 2D thermoelectrics for future applications.

Strong Anharmonicity‐Induced Low Thermal Conductivity and High n‐type Mobility in the Topological Insulator Bi1.1Sb0.9Te2S

“…BSTS exhibits intrinsically low κ lat along both the SPS ∥ and SPS ⊥ directions (Figure 2b), which is close to its theoretical κ min (0.26 Wm −1 K −1 ) calculated from Cahill's formula [51] . The κ lat of BSTS at SPS ∥ reaches an ultralow value of ≈0.46 at 573 K which is lower than other bismuth chalcogenides topological quantum material such as Bi 2 Te 3 , BiTe, Bi 2 Se 3 , and BiSe at this temperature range [39, 40, 52, 53] . To understand the origin of such ultra‐low κ lat , we have recorded C p data as function of temperature in the 2–150 K range.…”

Graphene-Based Thermoelectrics

“…Graphene, as one typical two-dimensional (2D) material − composed of a monolayer of sp 2 -hybridized carbon atoms, has been considered a highly competitive candidate for flexible TE applications in consideration of its innate merits of being nontoxic and lightweight in composition and having high flexibility and thermal stability in mechanics, ultrahigh intrinsic carrier mobility (μ) in electrical transport, and scalable synthesis in manufacturing. Besides, TE properties of graphene itself can be fine-tuned by modification or functionalization through doping or designing nanostructure defects .…”

Comprehensive Insights into Synthesis, Structural Features, and Thermoelectric Properties of High-Performance Inorganic Chalcogenide Nanomaterials for Conversion of Waste Heat to Electricity

“…(h) AFM close-up and height profile of the interface between two Bi 2 Se 3 flakes. Reprinted with permission from ref . Copyright 2019 American Chemical Society.…”

“…Wu et al 119 showed that σ of Bi 2 Se 3 can be enhanced by the introduction of graphene by 1D texturing. They successfully obtained a maximum ZT of 1.03.…”