Study of structural, optical and electrical properties of solution processed Cu2CoSnS4 absorber layer for thin film solar cells

Cu₂CoSnS₄ (CCTS) nanoparticles with 8-12 nm were synthesized by a robust, solvent free, single step, thermal decomposition process for the first time. Nanoparticle based ink was coated over fluorine doped tin oxide (FTO), soda lime glass (SLG) substrate via an inexpensive spin coating process to form films. The diffusion of sodium from SLG substrate was found to have an effect on band gap and resistivity of the CCTS film. The photoelectric response under light illumination (AM1.5, 100 mW/cm²) and optimum optical band gap (1.4-1.5 eV) of CCTS film indicate it to act as a promising cost effective absorber layer for thin film solar cells.