Pulsed electrodeposition of Cu2ZnSnS4 absorber layer precursor for photovoltaic application

• Potentiostatic pulse plated CZT precursor film from pyrophosphate bath
• Fabricated CZTS film from sulfurization of co-electrodeposited CZT precursor film
• Kesterite structured CZTS film with secondary phases is observed.
• Amount of secondary phases is reduced by increasing the annealing time.
• Obtained bandgap of CZTS films is 1.5 eV, suitable for solar cell applications.

Cu2ZnSnS4 (CZTS), comprising of earth abundant and non-toxic elements, is an ecofriendly and cost effective thin film absorber layer for solar cell applications. The present work describes the fabrication of p-type absorber material Cu2ZnSnS4 (CZTS) from alkaline pyrophosphate solution through pulsed electrodeposition (PED) at room temperature. CZTS thin film is prepared from one step co-electrodeposited Cu–Sn–Zn (CZT) precursor film obtained from pyrophosphate bath under potentiostatic condition (− 1.4 V) onto a Ni substrate followed by annealing in sulfur atmosphere at 500 °C for 1 h and 30 min. To achieve the desired CZTS stoichiometry in the deposited material, applied potential for the co-deposition has been calculated from the Tafel plots. The crystallographic phases, morphology and composition of the electrodeposited Cu–Sn–Zn precursor and the sulfurized films are assessed through X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), respectively. Formation of CZTS phase is confirmed from X-ray diffraction and Raman spectroscopy of the sulfurized sample. Optical band gap measurement is investigated by using UV–Vis absorption spectroscopy. The CZTS thin film of kesterite structure is obtained with a band gap of 1.5 eV, which is suitable for solar cell fabrication.