Controllable Synthesis of Stoichiometric Cu2ZnSnS4 Nanoparticles by Solvothermal Method and Its Properties

This work reports the solvothermal synthesis of earth abundant Cu2ZnSnS4 (CZTS) nanoparticles and their structural, morphological, chemical and optical properties. The X-ray diffraction and Raman spectroscopy confirmed the formation of single phase CZTS with kesterite crystal structure. Transmission electron microscopy showed the formation of well-dispersed CZTS nanoparticles having a size similar to 6 to12 nm. The stoichiometric ratio of relative elemental of Cu: Zn: Sn: S is confirmed from the energy dispersive spectrometer. The optical absorption studies revealed that CZTS nanoparticles had an optical band gap of 1.52 eV, which is the optimal for the photovoltaic applications. The surfactant HMTA plays a key role in the synthesis of CZTS nanoparticles. Finally, a possible reaction mechanism for the formation of CZTS nanoparticles is proposed.