The stability and reproducibility of the electric properties in n-type doped ZnO represent known bottlenecks towards potential thermoelectric applications. The degradation is promoted by the vanishing of the electronic defects on oxidation and irreversible exsolution of the phase impurities. This work proposes a microstructural mechanism showing that these processes take place mainly in the pores and highlighting the necessity for high densification of ZnO-based thermoelectrics to ensure more stable operation. The electrical performance was monitored at various temperatures, followed by a detailed microstructural analysis. The evolution of the electrical conductivity and Seebeck coefficient confirm that the degradation is related to a gradual decrease in the charge carrier concentration rather than to the effects suppressing their mobility. The results suggest that the donor exsolution may promote an increase or decrease of the power factor, guided by the self-optimization of the charge carrier concentration.

n型掺杂ZnO中电性能的稳定性和可再现性代表了潜在热电应用的已知瓶颈。氧化过程中电子缺陷的消失和相杂质的不可逆溶出促进了降解。这项工作提出了一种微观结构机理，表明这些过程主要发生在孔中，并突出了高致密化ZnO基热电材料以确保更稳定运行的必要性。在各种温度下监测电性能，然后进行详细的微观结构分析。导电率和塞贝克系数的演变证实，这种退化与电荷载流子浓度的逐渐降低有关，而不是与抑制其迁移率的作用有关。