Rapid synthesis of Cu2ZnSnS4 nanocrystalline thin films directly on transparent conductive glass substrates by microwave irradiation

• Cu2ZnSnS4 nanocrystalline thin films were synthesized directly on FTO substrates.
• A single-step microwave-assisted solution method without toxic chemicals is used.
• XRD, Raman, HRTEM, and XPS confirmed the formation of single kieserite Cu2ZnSnS4 phase.
• Cu2ZnSnS4 thin films are composed of uniform sphere-like nanocrystalline particles.

In this letter, a rapid and single-step microwave-assisted solution method was proposed to grow Cu2ZnSnS4 (CZTS) thin films directly on transparent conductive fluorine-doped tin oxide (FTO) substrates. The CZTS thin films synthesized in one pot without any post-treatment are characterized by X-ray diffraction, Raman spectroscopy, scanning electronic microscope, transmission electron microscopy, X-ray photoelectron spectrometer and UV–vis spectrophotometer. The CZTS thin films were single kesterite structure and composed of uniform sphere-like nanocrystalline particles with an average diameter of about 250 nm. The optical band gap is found to be 1.58 eV, which is suitable for photovoltaic applications.