Li Yichen, Su Jingyi, Wen Yi, Gao Dezheng, Chen Pengpeng, Zhao Zihao, Gao Tian, Wang Siqi, Liu Shan, Hu Yixuan, Liu Dongrui, Gao Xiang, Xie Hongyao, Zhao Li-Dong
School of Materials Science and Engineering, Beihang University, Beijing, 100191, China.
Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing, 100094, China.
Small. 2025 Sep;21(35):e2506188. doi: 10.1002/smll.202506188. Epub 2025 Jul 14.
Recently, diamondoid compounds have attracted significant attention in thermoelectrics due to their unique transport properties, with ZT beyond 1.6 reported in several p-type systems. In contrast, n-type diamondoid compounds remain largely unexplored. This work systematically investigates the transport properties of the novel n-type diamondoid material AgInSe, enhancing its thermoelectric performance through Ga doping and CdSe alloying. Additionally, its power generation potential is assessed using a single-leg device. These findings show that intrinsic AgInSe possesses a light conduction band with a low density-of-state effective mass of 0.13 m, leading to a high electron mobility of ∼650 cm Vs at room temperature. Furthermore, Ga is found to exist in dual oxidation states of Ga and Ga in AgGaInSe. The incorporation of Ga effectively increases the carrier concentration and electrical conductivity, while Ga introduces lone-pair electrons that enhance lattice anharmonicity. This synergistic modulation of electronic and phonon transport leads to a 274% improvement in ZT, reaching 0.74 at 873 K for AgGaInSe. Further alloying CdSe into AgGaInSe leads to partial substitution of Cd at the Ag sublattice, significantly increasing the carrier concentration and power factor. Simultaneously, CdSe incorporation induces dislocation arrays that intensify phonon scattering and further reduce thermal conductivity. These combined effects yield a maximum ZT of ≈1.2 and a decent average ZT of 0.55 in AgGaInSe-0.03CdSe.
最近，类金刚石化合物因其独特的输运特性在热电学领域引起了广泛关注，在几个p型体系中报道的ZT值超过了1.6。相比之下，n型类金刚石化合物在很大程度上仍未得到充分研究。这项工作系统地研究了新型n型类金刚石材料AgInSe的输运特性，通过Ga掺杂和CdSe合金化提高其热电性能。此外，使用单腿器件评估了其发电潜力。这些研究结果表明，本征AgInSe具有一个轻导带，态密度有效质量低至0.13m，导致室温下电子迁移率高达~650cm²V⁻¹s⁻¹。此外，发现Ga在AgGaInSe中以Ga⁺和Ga³⁺的双重氧化态存在。Ga的掺入有效地增加了载流子浓度和电导率，而Ga³⁺引入孤对电子增强了晶格非谐性。这种对电子和声子输运的协同调制使ZT提高了274%，在873K时AgGaInSe的ZT值达到0.74。进一步将CdSe合金化到AgGaInSe中导致Cd在Ag亚晶格处部分取代，显著增加了载流子浓度和功率因子。同时，CdSe的掺入诱导位错阵列，加剧声子散射并进一步降低热导率。这些综合效应在AgGaInSe-0.03CdSe中产生了最大ZT值约为1.2和体面的平均ZT值0.55。
