A Mild Hydrothermal Route To Synthesis Of Czts Nanoparticle Inks For Solar Cell Applications

Cu2ZnSnS4 (CZTS) is a promising thin film absorber material for low cost solar cell applications. Its absorption coefficient (similar to 10(4) cm(-1)), crystal structure and band gap energies (similar to 1.5 eV) are similar to those of Cu(In,Ga)Se-2 (CIGS), one of the most studied and flourishing thin film solar cell absorber materials. However, unlike CIGS, which requires the expensive and rare elements; In and Ga, CZTS is composed of reasonably priced and abundant elements like Zn and Sn. In the present investigation, kesterite CZTS nanoparticle inks were obtained by a hydrothermal process using Cu, Zn and Sn chlorides, and Na sulfide. The synthesized CZTS nanoparticles were characterized using optical absorption, X-ray powder diffraction (XRD), energy dispersive spectroscopy (EDS), micro-Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). The optical and morphological properties demonstrated that the prepared nanoparticles have strong absorption in 300-550 nm range with band gap energy of 1.55 eV with an average particle size of 20 nm. The X-ray and micro-Raman analysis revealed that the synthesized CZTS nanoparticles have the phase pure kesterite structure. We believe that our synthetic method will be helpful for low-cost and efficient thin film photovoltaic technology.