An investigation of rapidly synthesized Cu_2ZnSnS_4 nanocrystals

摘要

A detailed understanding regarding rapidly synthesized Cu_2ZnSnS_4 (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.