KNbO3 photoelectrode for DSSC: a structural, optical and electrical approach

Abstract

In this work, we present the potassium niobate (KNbO₃) nanoparticles as a suitable mesoporous photoelectrode for dye-sensitized solar cells (DSSCs). The KNbO₃ particles were synthesized by the microwave-assisted hydrothermal method using mild conditions and characterized by SEM, XRD, Raman, and UV-Vis diffuse reflectance. The particles presented a pyramidal tower-like shape with an orthorhombic structure and an indirect bandgap of (3.0 ± 0.1) eV. Dye-sensitized solar cells were assembled using the synthesized KNbO₃ nanoparticles, which were deposited as a photoelectrode on a TiO₂ recombination charge blocking layer. It is noticeable that the synergistic operation of the TiO₂ blocking layer and KNbO₃ photoelectrode is essential to achieve photovoltaic behaviour in our solar cells. The short-circuit current density of J_sc = 2.82 mA, open-circuit voltage V_oc = 669 mV, fill factor FF = 0.62, and a power conversion efficiency PCE = 1.17%, reports elevated parameters if compared to other DSSCs alternative materials, becoming potassium niobate suitable as photoelectrode.