An innovative approach for fabrication of Cu2ZnSnSe4 absorber layers using solutions of elemental metal powders

An innovative approach has been demonstrated for the deposition of Cu2ZnSnSe4 (CZTSe) absorber layers. Using a unique, safe solvent combination, moving away from hydrazine, elemental Cu, Zn, Sn and S/Se can be fully dissolved at ambient conditions, with the composition easily controlled. The preparation and the spray deposition of these solutions are performed in air, allowing a quick, easy and inexpensive process. Upon selenisation, large crystals are observed which are identified as the CZTSe kesterite phase using X-ray diffraction and Raman, the latter showing no distinctive signs of any binary or ternary secondary phases. Using this method, CZTSe absorber layers have been prepared for use in thin-film solar cells reaching efficiency of 3.2%. With further device optimisation, improved device performance will be achieved.