Latronico Giovanna, Mele Paolo, Artini Cristina, Manfrinetti Pietro, Pan Sian Wei, Kawamura Yukihiro, Sekine Chihiro, Singh Saurabh, Takeuchi Tsunehiro, Baba Takahiro, Bourgès Cédric, Mori Takao
Shibaura Institute of Technology, Omiya Campus, 307 Fukasaku, Minuma-ku, Saitama City 337-8570, Saitama, Japan.
Department of Chemistry and Industrial Chemistry, University of Genova, Via Dodecaneso 31, 16146 Genova, Italy.
Materials (Basel). 2021 Oct 2;14(19):5773. doi: 10.3390/ma14195773.
Filled skutterudites are currently studied as promising thermoelectric materials due to their high power factor and low thermal conductivity. The latter property, in particular, can be enhanced by adding scattering centers, such as the ones deriving from low dimensionality and the presence of interfaces. This work reports on the synthesis and characterization of thin films belonging to the Sm(FeNi)Sb-filled skutterudite system. Films were deposited under vacuum conditions by the pulsed laser deposition (PLD) method on fused silica substrates, and the deposition temperature was varied. The effect of the annealing process was studied by subjecting a set of films to a thermal treatment for 1 h at 423 K. Electrical conductivity and Seebeck coefficient were acquired by the four-probe method using a ZEM-3 apparatus performing cycles in the 348-523 K temperature range, recording both heating and cooling processes. Films deposited at room temperature required three cycles up to 523 K before being stabilized, thus revealing the importance of a proper annealing process in order to obtain reliable physical data. XRD analyses confirm the previous result, as only annealed films present a highly crystalline skutterudite not accompanied by extra phases. The power factor of annealed films is shown to be lower than in the corresponding bulk samples due to the lower Seebeck coefficients occurring in films. Room temperature thermal conductivity, on the contrary, shows values comparable to the ones of doubly doped bulk samples, thus highlighting the positive effect of interfaces on the introduction of scattering centers, and therefore on the reduction of thermal conductivity.
由于填充方钴矿具有高功率因数和低导热率，目前它们作为有前景的热电材料而被研究。尤其是后一种特性，可以通过添加散射中心来增强，比如那些源于低维结构和界面存在的散射中心。本文报道了属于Sm(FeNi)Sb填充方钴矿体系的薄膜的合成与表征。通过脉冲激光沉积（PLD）方法在真空条件下将薄膜沉积在熔融石英衬底上，并改变沉积温度。通过对一组薄膜在423 K下进行1小时的热处理来研究退火过程的影响。使用ZEM - 3仪器通过四探针法在348 - 523 K温度范围内进行循环，记录加热和冷却过程，从而获得电导率和塞贝克系数。在室温下沉积的薄膜在达到523 K并稳定之前需要三个循环，这表明适当的退火过程对于获得可靠的物理数据很重要。XRD分析证实了先前的结果，因为只有退火后的薄膜呈现出高度结晶的方钴矿且没有伴随额外的相。由于薄膜中的塞贝克系数较低，退火薄膜的功率因数低于相应的块状样品。相反，室温下的热导率显示出与双掺杂块状样品相当的值，从而突出了界面在引入散射中心以及因此在降低热导率方面的积极作用。
