Thermoelectric Cooling-Oriented Large Power Factor Realized in N-Type Bi2Te3 Via Deformation Potential Modulation and Giant Deformation

Abstract

Thermoelectric refrigeration, utilizing Peltier effect, has great potential in all-solid-state active cooling field near room temperature. The performance of a thermoelectric cooling device is highly determined by the power factor of consisting materials besides the figure of merit. In this work, it is demonstrated that successive addition of Cu and Nd can realize non-trivial modulation of deformation potential in n-type room temperature thermoelectric material Bi₂Te_2.7Se_0.3 and result in a significant increment of electron mobility and remarkably enhanced power factor. Following giant hot deformation process improves grain texturing and strengthens inter-layer interaction in Bi₂Te_2.7Se_0.3 lattice, further pushing the power factor to ≈47 µW cm⁻¹ K⁻² at 300 K and maximal figure of merit ZT_max to ≈1.34 at 423 K with average ZT_ave of ≈1.27 at 300–473 K. Moreover, robust compressive strength is enhanced to ≈146.6 MPa. The corresponding finite element simulations demonstrate large temperature differences ΔT of ≈70 K and a maximal coefficient of performance COP ≈ 10.6 (hot end temperature at 300 K), which can be achieved in a ten-pair thermoelectric cooling virtual module. The strategies and results as shown in this work can further advance the application of n-type Bi₂Te₃ for thermoelectric cooling.