The limited availability of Te poses challenges for the widespread application of Bi₂Te₃-based thermoelectric modules. In this work, we explored the thermoelectric module potential of Te-free PbSe by elevating its power factor through crystal growth and slight-tuning vacancy and interstitial defects. The outcomes revealed a gradual increase in the carrier concentration and a high room-temperature carrier mobility of ∼1750 cm² V⁻¹ s⁻¹, leading to an enhanced power factor of ∼37.4 μW cm⁻¹ K⁻² in Pb_1.006Se+0.0016 Al crystals. We grew PbSe crystals to minimize the impact of grain boundaries on the charge carrier transport. Subsequently, n-type PbSe crystals were produced by introducing extra Pb to occupy the intrinsic Pb vacancies, effectively minimizing vacancy scattering. Following this, a minute quantity of small-sized Al (≤2‰) was introduced, revealing that these surplus Al atoms served as cationic dopants, substituting for Pb, while also occupying interstitial positions. The interstitial doping increases the carrier concentration while maintaining carrier mobility due to the distinct dimensions between the interstitial atoms and mean free path of electrons. The consistently improved power factor with the suppression of thermal conductivity brings about a significantly high ZT value over the whole temperature. Specifically, the ZT values of the Pb_1.006Se+0.0016Al crystal reached ∼0.5 at 300 K, ∼1.5 at 673 K, and the average ZT (ZT_ave) reached ∼1.1 at 300–773 K. Ultimately, a single-leg power generation efficiency ∼7.1% was achieved in Pb_1.006Se+0.0016Al crystal and a 7-pair module reached a maximum temperature cooling difference ∼51.2 K at the high temperature side T_h of 363 K. These results indicate the potential for developing a cost-effective and high-performance thermoelectric module utilizing PbSe.

中文翻译：

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通过优化n型PbSe晶体中的载流子迁移率来提高功率因数，实现高性能热电模块

Te的有限供应给Bi ₂ Te ₃基热电模块的广泛应用带来了挑战。在这项工作中，我们通过晶体生长和微调空位和间隙缺陷来提高功率因数，从而探索了无碲 PbSe 的热电模块潜力。结果表明， Pb _1.006 Se中载流子浓度逐渐增加，室温载流子迁移率高达 ∼1750 cm ² V ^-1 s ^-1，导致功率因数提高到 ∼37.4 μW cm ^-1 K ^-2 +0.0016 铝晶体。我们生长 PbSe 晶体，以尽量减少晶界对载流子传输的影响。随后，通过引入额外的 Pb 来占据本征的 Pb 空位，从而有效地减少空位散射，从而制备了 n 型 PbSe 晶体。随后，引入了微量的小尺寸Al（≤2‰），表明这些多余的Al原子作为阳离子掺杂剂，取代了Pb，同时也占据了间隙位置。由于间隙原子和电子的平均自由程之间的不同尺寸，间隙掺杂增加了载流子浓度，同时保持了载流子迁移率。不断提高的功率因数和抑制热导率带来了整个温度范围内显着高的ZT值。具体来说，Pb _1.006 Se+0.0016Al晶体的ZT值在300 K时达到~0.5，在673 K时达到~1.5，平均ZT（ZT _ave）在300-773 K时达到~1.1。最终，单腿Pb _1.006 Se+0.0016Al 晶体的发电效率达到约 7.1% ，7 对模块在高温侧T _h为 363 K时达到最大温差约 51.2 K。这些结果表明开发采用 PbSe 的经济高效且高性能的热电模块。