Optoelectronic and Photovoltaic Properties of the Cu₂ZnSnS₄Photocathode by a Temperature-Dependent Facile Hydrothermal Route

In the present work, a one-step hydrothermal route was performed to develop the Cu2ZnSnS4 (CZTS) photoelectrode onto a conducting substrate. The photovoltaic performance of the homojunction CZTS photocathode was analyzed with a two-electrode cell system of FTO/CZTS/(0.3 M Eu3+-Eu2+)aq/graphite. An increase in reaction temperature shows a decrease in the band gap energy from 1.54 to 1.44 eV. The evolution of the kesterite CZTS structure with uniform and dense nanospheres was confirmed by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) studies. High resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) evaluations confirm the formation of polycrystalline thin films. The photoelectrochemical solar cell properties of CZTS (C1-C3) thin films demonstrate an increase in photoconversion efficiency (η) from 2.55 to 4.87% as a function of reaction temperature. The improvement in electrical conductivity and generation of lower Rct and Rs of (C1-C3) thin films were confirmed using electrochemical impedance spectroscopy.