1. Removal of secondary phases and its effect on the transport behavior of Cu2ZnSn1-xGexS4 kesterite nanoparticles.
- Author
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Enrique Cancino-Gordillo, Francisco, Ortiz-Quiñonez, José-Luis, Pal, Mou, Silva González, Rutilo, and Pal, Umapada
- Subjects
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KESTERITE , *CHEMICAL processes , *ZINC sulfide , *SOLAR cell efficiency , *COPPER , *CARRIER density - Abstract
[Display omitted] • Ge beyond x ∼ 0.4 in kesterite Cu 2 ZnSn 1-x Ge x S 4 causes the formation of secondary phases. • We could eliminate those secondary phases by an acid etching process. • The acid etching process does not affect the size and morphology of the nanostructures. • The phase pure kesterite films manifest high conductivity and enhanced hole concentration. Hole-transporting materials are very important for achieving high efficiency in perovskite solar cells. Thin films made of Cu 2 ZnSn 1-x Ge x S 4 have attracted the attention of researchers due to their potential as hole-transporting layers. However, defects and impurities define their effectiveness in solar cells. In this work, we present a facile wet chemical approach to remove the ZnS and Cu 8 GeS 6 impurities from small (∼11 nm) Cu 2 ZnSn 1-x Ge x S 4 (x = 0.0 to 0.7) nanoparticles synthesized by a hydrothermal process. The wet chemical process converted the nanostructures Cu-rich Zn-poor from their initial Zn-rich Cu-poor stoichiometry. Moreover, the bandgap energies of the nanostructures were reduced by about 0.1 eV after chemical treatment due to change the oxidation state of Cu from Cu1+ to Cu2+. The kesterite films prepared by spin coating of chemically treated nanoparticle inks revealed enhanced electrical conductivity and hole concentration in comparison to the films prepared using untreated nanoparticle inks. While the highest hole concentration of about 6.52x1018 cm−3 was obtained for the films made of Cu 2 ZnSn 1-x Ge x S 4 nanoparticles with the highest x value (x = 0.7), the highest hole mobility (18.9 cm2V−1s−1) was achieved for x = 0.3. The effects of secondary phase elimination on carrier concentration and mobility variation have been discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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