Contrasting Thermoelectric Transport Behaviors of p-Type PbS Caused by Doping Alkali Metals (Li and Na).

Zhenghao Hou,Dongyang Wang,Li-Dong Zhao,Guangtao Wang,Zhiwei Huang,Jinfeng Wang

doi:10.34133/2020/4084532

Zhenghao Hou, Dongyang Wang + Show 4 more

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https://doi.org/10.34133/2020/4084532

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Abstract

PbS is a latent substitute of PbTe thermoelectric materials, which is on account of its superiority in low cost and earth abundance. Here, the thermoelectric transport properties of p-type PbS by doping alkali metals (Na and Li) are investigated and it is verified that Li is a more effective dopant than Na. By introducing Li, the electrical and thermal transport properties were optimized collectively. The electrical transport properties were boosted remarkably via adjusting carrier concentration, and the maximum power factor (PFmax) of ~11.5 μW/cmK2 and average power factor (PFave) ~9.9 μW/cmK2 between 423 and 730 K in Pb0.99Li0.01S were achieved, which are much higher than those (~9.5 and ~7.7 μW/cmK2) of Pb0.99Na0.01S. Doping Li and Na can weaken the lattice thermal conductivity effectively. Combining the enlarged PF with suppressed total thermal conductivity, a maximum ZT ~0.5 at 730 K and a large average ZT ~0.4 at 423-730 K were obtained in p-type Pb0.99Li0.01S, which are higher than ~0.4 and ~0.3 in p-type Pb0.99Na0.01S, respectively.

Highlights

The search for reliable and environmentally friendly new energy has attracted worldwide attention because of the shortage of fossil energy
The thermoelectric device efficiency is positively associated with the dimensionless figure of merit [6,7,8,9], ZT = S2σT/κtot, where T represents absolute temperature, S expresses the Seebeck coefficient, σ denotes electrical conductivity, and κtot represents total thermal conductivity comprising electronic and lattice contributions [2, 10, 11]
Aimed at solving the shortcomings of PbS, the approaches including carrier concentration optimization [17], band manipulation [18], and microstructure engineering [19,20,21,22] have been proved as effective strategies to manipulate electrical properties and thermal conductivity; the achievements realized through the above strategies well elucidate the potential performance of PbS

Summary

Introduction

The search for reliable and environmentally friendly new energy has attracted worldwide attention because of the shortage of fossil energy. A thermoelectric device is capable of transforming heat into electric energy immediately, which has shown great prospect in clean energy field [1,2,3,4,5]. Lead telluride- (PbTe-) based materials, as a kind of medium-temperature operating materials, have attracted extensive research interests on account of outstanding thermoelectric performance [12,13,14]. One research hotpot in this field is to find an alternative material to substitute PbTe which possesses prominent thermoelectric properties [14,15,16]. The poor electrical properties and large lattice thermal conductivity historically make PbS become an inferior thermoelectric material [11]. Aimed at solving the shortcomings of PbS, the approaches including carrier concentration optimization [17], band manipulation [18], and microstructure engineering [19,20,21,22] have been proved as effective strategies to manipulate electrical properties and thermal conductivity; the achievements realized through the above strategies well elucidate the potential performance of PbS

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