An investigation of rapidly synthesized Cu2ZnSnS4 nanocrystals

• Rapid synthesis of Cu2ZnSnS4 nanocrystals was carried out.
• An asymmetric Raman peak broadening was observed for shorter synthesis duration.
• Detailed investigation, based on weighted Lorentzian contributions was performed.
• Occurrence of phonon and quantum confinement.
• Synthesis of 4 nm size CZTS nanocrystal.

A detailed understanding regarding rapidly synthesized Cu2ZnSnS4 (CZTS) nanocrystal processing parameters, their correct phase identification, size and shape analysis, and optoelectronic performance evaluation are essential in order to produce high quality nanocrystals. The structural and optical properties were investigated using X-ray diffraction, Raman spectroscopy, UV–vis spectroscopy, atomic force microscopy, and transmission electron microscopy (TEM). Wavenumber shift and broadening of Raman linewidth indicate reduction in CZTS crystal dimension and subsequent occurrence of phonon confinement. An asymmetric Raman peak broadening was also observed when the duration of synthesis was reduced from 18 min to 8 min. In-depth investigation, based on weighted Lorentzian contributions, suggests that the sizes of CZTS crystals are more uniform when synthesis duration is longer. Optical characterization results indicate ‘occurrence of quantum confinement effect’ which was corroborated by TEM observation. Electrical and photoelectrochemical characterization suggest utility of these nanocrystals for photovoltaic applications.