Profound Impact of Zn₃(OH)₂(V₂O₇)(H₂O)₂ and Zn₃V₂O₈–Zn₂V₂O₇ in Dye Sensitized Solar Cells

Zinc vanadium oxide (ZV) nanoflake (50 nm size) working electrodes (WE) for dye sensitized solar cells (DSSCs) were successfully prepared by a one-step precipitation method. XRD and FE-SEM were utilized to depict the crystal structure and morphology of the produced ZV nanoflakes. XRD showed that the pristine dried sample at 60 °C (ZV-60) was assembled mainly of the hydrated phase of zinc hydroxide vanadium oxide (Zn₃(OH)₂V₂O₇), whereas two other pure phases of ZV were detected and indexed as Zn₃V₂O₈ and Zn₂V₂O₇ after calcination at 400 °C. Higher conversion efficiency (η) of solar light was obtained using calcined ZV at 400 °C (ZV-400) as the WE. The light-to-electricity conversion reached 6.8% upon using ZV-60, whereas it reached 2.7% when ZV-400 was used as the WE. This might be due to the high ionic mobility because of the extremely architecture porous structure of the crystal lattice and/or increased conductivity due to presence of crystalline water in case of the ZV-60 phase.