Pulsed electrodeposition of Cu2ZnSnS4 absorber layer precursor for photovoltaic application

Publication date: 1 February 2016
Source:Thin Solid Films, Volume 600
Author(s): Sushmita Chaudhari, Srinivas Palli, Kannan P.K., Suhash R. Dey
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 (−1.4V) onto a Ni substrate followed by annealing in sulfur atmosphere at 500°C for 1h and 30min. 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 1.5eV, which is suitable for solar cell fabrication.