Growth and reaction mechanism of solution-processed Cu2ZnSnSe4 thin films for realising efficient photovoltaic applications

This article reports on Cu2ZnSnSe4 (CZTSe) thin film preparation via a nonhydrazine, nonpyridine and environmentally friendly low-cost solution process method. CZTSe fabrication through a solution-based process has not yet been suitably demonstrated given the impediments to addressing the presence of selenium in solutions. In this study, we introduced a two-step CZTSe fabrication method that used monoethanolamine as the chelating agent/co-solvent and ethanol as the main solvent. Selenization was then conducted. In this process, we successfully avoided the use of hydrazine to synthesise CZTSe thin films. Material characterisations (e.g. UV-VIS-NIR, scanning electron microscopy, electron dispersive spectroscopy, X-ray diffractometry and Fourier transform infrared spectroscopy) confirmed the high quality of the deposited thin films. The deposited CZTSe thin film showed high crystallinity without carbon residues, indicating its potential application as a photovoltaic absorber. Hence, we investigated the photovoltaic parameters of the CZTSe-based solar cells on the basis of the deposited thin film's optoelectronic properties. We utilised Solar Cell Capacitance Simulator to examine the electrical effects of CZTSe solar cells and used three-dimensional finite-difference time-domain optical simulations to investigate the optics of the solar cells. We estimated that the realistic power conversion efficiency of the CZTSe solar cells could reach 18.5% with a short-circuit current density of 30 mA/cm(2). (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study demonstrates the preparation of high-quality CZTSe thin films through an environmentally friendly low-cost solution process, avoiding the use of toxic chemicals. The deposited films exhibit high crystallinity and no carbon residues, showing potential as a photovoltaic absorber. Realistic power conversion efficiency of CZTSe solar cells is estimated to reach 18.5% with a short-circuit current density of 30 mA/cm(2).