Decoupling Carrier-Phonon Scattering Boosts the Thermoelectric Performance of n-Type GeTe-Based Materials

Abstract

The coupled relationship between carrier and phonon scattering severely limits the thermoelectric performance of n-type GeTe materials. Here, we provide an efficient strategy to enlarge grains and induce vacancy clusters for decoupling carrierphonon scattering through the annealing optimization of n-type GeTe-based materials. Specifically, boundary migration is used to enlarge grains by optimizing the annealing time, while vacancy clusters are induced through the aggregation of Ge vacancies during annealing. Such enlarged grains can weaken carrier scattering, while vacancy clusters can strengthen phonon scattering, leading to decoupled carrier-phonon scattering. As a result, a ratio between carrier mobility and lattice thermal conductivity of ∼492.8 cm 3 V −1 s −1 W −1 K and a peak ZT of ∼0.4 at 473 K are achieved in Ge 0.67 Pb 0.13 Bi 0.2 Te. This work reveals the critical roles of enlarged grains and induced vacancy clusters in decoupling carrier-phonon scattering and demonstrates the viability of fabricating high-performance n-type GeTe materials via annealing optimization.

All-SnTe-Based Thermoelectric Power Generation Enabled by Stepwise Optimization of n-Type SnTe

“…This device could achieve a maximum output power of ∼0.2 W and a peak conversion efficiency of ∼2.7% at a temperature difference of 350 K, being a significant breakthrough for promoting the environmentally friendly all-SnTe-based thermoelectric power generation. Our findings demonstrate the significant achievement in developing both n-type SnTe materials and all-SnTe-based devices, and the stepwise strategy might also be implemented in other similar systems such as n-type GeTe and n-type BiCuSeO. − …”

Effects of working pressure during magnetron sputtering on thermoelectric performance of flexible p-type Bi0.5Sb1.5Te3 thin films

“…Bi 2 Te 3 -based alloys are most widely used for power generation and refrigeration in low temperature ranges (<600 K). 3 In recent years, a traditional middle-temperature (500-800 K) material GeTe has been well advanced in TE performance within a wide temperature range of 300-723 K. 4,5 However, thermal stability and manufacturing cost limit their industrial applications. In comparison with their bulk counterparts, Bi 2 Te 3 -based films offer a more lightweight, comfortable, and low-cost solution for wearable or miniature TE devices.…”

Into the Void: Single Nanopore in Colloidally Synthesized Bi2Te3 Nanoplates with Ultralow Lattice Thermal Conductivity

“…However, while the aforementioned strategies will enhance one or more thermoelectric properties, namely, the electrical resistivity, Seebeck coefficient, or thermal conductivity, they are often deleterious to the other properties. The carrier concentration of the material largely dictates the thermoelectric properties; thus, doping or alloying has limitations on the enhancement of thermoelectric performance. − Although, there have been recent examples where these interrelated properties have been decoupled, through interstitial doping or creating vacancies in specific materials. − Despite these material properties being dependent on carrier concentration, the thermal conductivity can be decoupled into electronic (κ e ) and lattice (κ L ) components, where κ = κ e + κ L . One method that has proven successful in decoupling these interwoven properties is nanostructuring, which has allowed for the realization of ultralow κ L …”

“… 7 − 11 Although, there have been recent examples where these interrelated properties have been decoupled, through interstitial doping or creating vacancies in specific materials. 12 − 15 Despite these material properties being dependent on carrier concentration, the thermal conductivity can be decoupled into electronic (κ e ) and lattice (κ L ) components, where κ = κ e + κ L . One method that has proven successful in decoupling these interwoven properties is nanostructuring, which has allowed for the realization of ultralow κ L .…”