Univerzita Pardubice Fakulta chemicko- technologická

Univerzita Pardubice

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Publikace detail

Difficulties in preparation of truly pure polycrystalline Bi2O2Se

Autoři: Sojka Antonín | Zich Jan | Navrátil Jiří

Rok: 2024

Druh publikace: ostatní - přednáška nebo poster

Strana od-do: nestránkováno

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
eng	Difficulties in preparation of truly pure polycrystalline Bi2O2Se	Bi2O2Se is a 2D layered material with potential applications in thermoelectrics. In this work, a series of polycrystalline Bi2O2Se samples with altered stoichiometry were prepared. They were characterized by X-ray diffraction, electrical conductivity, Seebeck coefficient and thermal conductivity. Thermoelectric (TE) data were measured as a function of temperature in the range of 300 K to 773 K. We came across a specific issue where significant variations in TE properties compared to the recently published data on undoped Bi2O2Se are apparent. Furthermore, even the published data from various sources are inconsistent. We also compared TE properties of published data on doped samples with our samples with altered stoichiometry and found similarities. Based on a thorough investigation, we have reached several conclusions that are relevant to this problem. We argue that the solubility of the doped elements is very limited. Instead, the doping process mainly induces changes in the stoichiometry of the parent Bi2O2Se. This is associated with formation of native point defects and foreign phases. It is worth noting that both native defects and foreign phases are mostly not observable by X-ray methods.