Quasi-Vertically Oriented Sb(2)Se(3) Thin-Film Solar Cells with Open-Circuit Voltage Exceeding 500 mV Prepared via Close-Space Sublimation and Selenization
Résumé
Sb(2)Se(3), one of the most desirable absorption materials for next-generation thin-film solar cells, has an excellent photovoltaic characteristic. The [hk1]-oriented (quasi-vertically oriented) Sb(2)Se(3) thin film is more beneficial for promoting efficient carrier transport than the [hk0]-oriented Sb(2)Se(3) thin film. Controlling thin-film orientation remains the main obstacle to the further improvement in the efficiency of Sb(2)Se(3)-based solar cells. In this work, the controlled [hk0] or [hk1] orientation of the Sb(2)Se(3) precursor is readily adjusted by tuning the substrate temperature and the distance between the source and the sample in close-space sublimation (CSS). Well-crystallized stoichiometric Sb(2)Se(3) thin films with the desired orientation and large crystal grains are successfully prepared after selenization. Sb(2)Se(3) thin-film solar cells in a substrate configuration of glass/Mo/Sb(2)Se(3)/CdS/ITO/Ag are fabricated with a power conversion efficiency of 4.86% with a record open-circuit voltage (V(OC)) of 509 mV. The significant improvement in V(OC) is closely related to the quasi-vertically oriented Sb(2)Se(3) absorber layer with reduced deep-level defect density in the bulk and defect passivation at the Sb(2)Se(3)/CdS heterojunction. This work indicates that CSS and selenization show a remarkable potential for the fabrication of high-efficiency Sb(2)Se(3) solar cells.
Domaines
Matériaux
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