Thin MEH-PPV organic interlayer strategy for achieving efficiency improvement in a kesterite Cu2ZnSnS4 electrochemically deposited solar cell

Cu 2 ZnSnS 4 (CZTS) thin films with controlled composition, phase, and uniformity were fabricated by sulfurization of stack layer electrodeposited on an MEH-PPV polymer thin film via a simple two-step process. Herein, we propose that used thin organic polymer interlayer passivate the interface defects fabricated by spin- coating method at the CZTS / molybdenum (Mo)back contact layer interface. The effect of the MEH-PPV interlayer type on the morphological, optical, compositional, electrical, and structural properties of the CZTS active layer was studied. Using MEH-PPV polymer, the cyclic voltammogram scan shows three cathodic peaks corresponding to the reduction peaks of the material ions. Raman scattering and X-ray diffraction analysis indicated that sulfurized CZTS films are pure as well as exhibit a high (112) orientation, a high value of crystallites, and a single kesterite structure. Investigation of the optical characteristics of CZTS thin films revealed a significant absorbance of 10 4 cm −1 , and the optical energy gap (Eg) value reduced from 1.89 to 1.59 eV with an decrease in the thickness of the polymer thin films. The analysis of the chemical composition of the deposited elements indicated that the Zn/Sn ratio is rich, while the Cu/(Zn + Sn) ratio is poor. X-ray photoelectron spectroscopy was utilized to confirm the existence of the four elements (Cu, Zn, Sn, and S) and study their oxidation states. Surface morphology studies demonstrated that the sample deposited on a 30-nm polymer is smooth, dense, crack-free, and uniformly deposited with a grain size of ∼3 µm. a SLG /Mo/polymer/CZTS/CdS/ i -ZnO/AZO/Ag structure was developed using a 30-nm MEH-PPV layer for the synthesis of a photovoltaic device that an exhibited short-circuit current density J sc of 23.85 mA/cm 2 , a fill factor FF of 69.4 %, open circuit voltage Voc of 0.527 mV and a conversion efficiency of 8.72 %.