The present joint experimental and theoretical work provides in-depth understanding on the morphology
and structural, electronic, and optical properties of ZnWO4 nanocrystals. Monoclinic ZnWO4 nanocrystals
were prepared at three different temperatures (140, 150, and 160 1C) by a microwave hydrothermal
method. Then, the samples were investigated by X-ray diffraction with Rietveld refinement analysis, fieldemission
scanning electron microscopy, transmission electronic microscopy, micro-Raman and Fourier
transform infrared spectroscopy, ultraviolet-visible spectroscopy, and photoluminescence measurements.
First-principles theoretical calculations within the framework of density functional theory were employed
to provide information at the atomic level. The band structure diagram, density of states, Raman and
infrared spectra were calculated to understand the effect of structural order–disorder on the properties of
ZnWO4. The effects of the synthesis temperature on the above properties were rationalized. The band
structure revealed direct allowed transitions between the VB and CB and the experimental results in the
ultraviolet-visible region were consistent with the theoretical results. Moreover, the surface calculations
allowed the association of the surface energy stabilization with the temperature used in the synthesis of
the ZnWO4 nanocrystals. The photoluminescence properties of the ZnWO4 nanocrystals prepared at 140,
150, and 160 1C were attributed to oxygen vacancies in the [WO6] and [ZnO6] clusters, causing a red
shift of the spectra. The ZnWO4 nanocrystals obtained at 160 1C exhibited excellent photodegradation of
Rhodamine under ultraviolet light irradiation, which was found to be related to the surface energy and the
types of clusters formed on the surface of the catalyst