n-type Bi-doped PbTe Nanocubes with Enhanced Thermoelectric Performance

Abstract

In this study, Bi was selected to dope PbTe nanocubes to develop high performance n-type PbTebased thermoelectric materials via nanostructure engineering using a facile solvothermal method. Bi dopants effectively improve the electrical transport properties of the as-sintered PbTe nanomaterials by tuning the carrier concentrations, achieving promising electrical conductivity and Seebeck coefficient which are comparable to bulk materials. Moreover, a low lattice thermal conductivity has been secured in the sintered Bi-doped PbTe nanomaterials, which is remarkably lower than its bulk counterparts. Extensive experimental and theoretical evidences reveal that such low lattice thermal conductivity is attributed to the enhanced phonon scattering by the high density of grain boundaries and dislocations, in turn, leading to an enhanced peak ZT ~1.35 at 675 K for n-type Pb 0.99 Bi 0.01 Te.

High Performance Thermoelectric Materials: Progress and Their Applications

“…Such strong phonon scattering can reduce κ L to almost 50% which can lead to an increase in ZT by a factor of 2. [73] Moreover, Hong et al [197] fabricated Bi 2 Se 3 nanosheets with controlled thickness. Such a strategy has been successfully applied and benefits the enhanced ZT in many material systems including Cu 2 Se, [48,72,195] Bi 2 Te 3 , [118,133,196] Bi 2 Se 3 , [197] and PbTe.…”

“…[131] Copyright 2014, AIP Publishing. [88,120,243] High density dislocations can also be induced by varying the Na concentration in Eu-doped PbTe when tuning n using Na, [89] or using rapid spark plasma sintering (SPS) for nanostructures, [48,72,73,118,195] leading to dramatically reduced κ L . Reproduced with permission.…”

“…Based on the fundamental understandings on TEs, tremendous efforts have been devoted to achieve ZT > 2, such as in Bi 2 Te 3 / Sb 2 Te 3 superlattice, [66] PbTe, [67] SnSe, [47,68] and Cu 2 Se, [69] in addition to extensive achievement of ZT values above unity. [48,[70][71][72][73] Table 1 summarizes the current progress with ZT >1.5 in the past five years, in which PbTe takes a very large part because of its intrinsically low κ caused by anharmonic phonon scattering, [74] its good electrical transport properties, and tunable band structure. [75,76] Cu 2 Se-and SnSe-based materials were newly realized as excellent TE materials because of the Cu ion liquid-like behavior [42] in Cu 2 Se, and ultralow κ L of SnSe due to the anharmonic scattering mechanism coming from the lone s-pair electrons, [47] which have been recognized in many chalcogenides.…”

Enhanced thermoelectric performance of Na-doped PbTe synthesized under high pressure

“…5d). The plastic deformation process under high pressure facilitates the formation of dense in-grain dislocations, which can scatter mid-frequency phonons and further lower the lattice thermal conductivity [23][24][25]44].…”

“…A diversity of approaches have been applied to PbTe-based materials for ZT enhancements, such as carrier concentration optimization [16,17], introduction of resonance level [18,19], electronic band engineering [6,20,21] and microstructure engineering [8,22]. Recent researches also highlight lattice dislocations as an effective phonon scattering source to further suppress the lattice thermal conductivity of lead chalcogenides [23][24][25][26]. For PbTe, the monovalent sodium has been verified as the most viable p-type dopant [17].…”