The attractive capability of thermoelectric (TE) materials in actualizing the conversion between temperature gradient and electrical power makes them strong candidates for waste-heat recovery as well as solid-state refrigeration [1,2,3]. The practical and widespread application of TE technology strongly relies on the development of high-performance TE materials, where the TE performance of materials is evaluated by a dimensionless figure of merit, zT = α²σT/κ. The TE parameters α and σ are the Seebeck coefficient and electrical conductivity which, respectively, constitute the power factor, PF = α²σ, used to evaluate electrical conductivity characteristics. Parameter T is the Kelvin thermodynamic temperature, while κ refers to the total thermal conductivity, which is composed of two major contributions from the charge carriers (κ_E) and the lattice (κ_L), respectively. From a computational perspective, the most ideal high-performance TE material should have a large α, high σ as well as a low κ value. What cannot be avoided is the strong coupling between thermoelectric parameters regarding carrier concentration, such as when a high σ means low α and a high κ_E, limiting the improvement of zT [4,5,6]. In order to achieve high zT in traditional or emerging TE materials, various methods and approaches have been adopted to reduce the correlation between thermal and electrical properties [7,8,9], including defect engineering, size effects, alloying effect and high-entropy engineering, etc. In addition to achieving high performance, the exploration of alternative materials consists of earth-abundant and eco-friendly components to meet the sake of clean and environmental protection is also considered as one of the most popular approaches in TE field [10,11,12,13]. In recent years, diverse bulk TE materials have been widely researched, including liquid-like Cu₂(S, Se, Te), silver-based chalcogenides, Sn(Te, S, Se), half-heuslers, etc. [14,15,16].

As an environmentally friendly and promising TE material without precious elements, the performance advantages of copper-based diamond-like TE compounds lie in their high Seebeck coefficient and low thermal conductivity [17,18,19,20,21]. Typical compounds include: Cu₃SbSe₄, with a high zT of 0.89 at 650 K [19]; Cu₂SnSe₃, with α of ~250 μV·K⁻¹ in the temperature range of 300–700 K [22]; and CuInTe₂, with a κ_L value as low as 0.3 W·m⁻¹·K⁻¹ [23], etc. Copper-based diamond-like TE compounds are a type of material that conforms to the concept of “phonon-glass electron-crystal” (PGEC) [17] materials, and their crystal structures are usually composed of two sublattices [23,24,25], in which one sublattice constitutes a conductive network, while the other acts as a thermal barrier and is sometimes also known as a charge reservoir. In 2011, Skoug et al. [24] summarized the significance of lone-pair electrons in the Cu-Sb-Se diamond-like system and demonstrated that the low intrinsic κ_L in compounds came from the interaction of lone-pair electrons with neighboring atoms. Moreover, Skoug et al. [25] also confirmed that the dominant Cu-Se network controlled the electric transport while the Sn orbitals only compensated the system for electrons. Several diamond-like crystal structures evolved from thecubic zincblende structure. Simultaneously, a series of advanced CBDL compounds have been discovered since 2009, most of which have presented outstanding TE properties. The timeline of maximum zTs and the temperature dependence of zTs for selected CBDL compounds. Taking the typical diamond-like compounds of Cu(In, Ga)Te₂, Cu₃SbSe₄, and Cu₂SnSe₃ as examples, long-term efforts have shown that they all apparently have superior TE transport properties with high zTs that exceed one. For instance, Liu et al. [23] devised a pseudocubic crystal structure in CuInTe₂ compounds; thus the highest zT of 1.24 was obtained in Ag-doped CuInTe₂ compounds. A peak zT of 1.14 was attained in a Cu₂Sn_0.90In_0.10Se₃ compound at 850 K by replacing Sn sites with In. It is also worth noting that a high average zT (zT_大道） 值对于整体 TE 转换效率是理想的。例如，高zT_.max在 1 K 时为 67.873，并且zT_大道的 0.73，以铜为单位实现_0.7银_0.3加语_0.4在_0.6特₂ [26]周氏课题组最新研究[27，28]创历史新高zT_大道铜中的值分别为 0.73 和 0.77₃锑硒₄-基和铜₃SbS₄分别基于材料，也可与其他最先进的TE化合物相媲美。因此，人们可以看到CBDL化合物有望成为TE应用的环保候选者，并实现优异的性能。

2. 铜基类金刚石热电化合物