Saeed Safa - Young Researchers and Elite Club, South Tehran Branch, Islamic Azad University, Tehran, Iran
Ali Khayatian - ۲Physics department, University of Kashan, Kashan, Iran.
eliza rokhsat - ۳Plasma Physics Research Center, Science and Research branch, Islamic Azad University, Tehran, Iran
Mehrdad Najafi - ۴Department of Physics, Shahrood University of Technology, Shahrood, Iran

ZnO nanorods with various aspect ratios (by changing the time of growth between ۰-۲۴۰ min) were synthesized using hydrothermal method and were investigated using XRD, SEM, UV–Vis and PL. It was found that growth time is directly coupled with the length, orientation and aspect ratio of the nanorod arrays. The optical transmittance of the NR arrays indicated a regular decrement of average transmittance with increasing the aspect ratio of NRs in the visible range. The optical constants (absorption coefficient, extinction coefficient and refractive index) can be account as a function of refractive index were determined. The porous ZnO nanorod with the thickness of ∼ ۱۵۶۰ nm and texture coefficient of ۰.۹۶ for (۰۰۲) plane exhibits the average visible transmittance <۶۰%, refractive index ۱.۳۴, packing density ۰.۲۶ and lowest optical band gap, was fabricated in the longest time of hydrothermal growth (۲۴۰ min). As the growth time was increased, the photoluminescence properties was sustained a general weakening tendency and a red-shift of UV-emission peak position. The UV-assisted photocatalytic degradation of ۴-Nitrophenol (۴-NP) of ZnO NRs were investigated. The considerable photocatalytic performance of ZnO NRs with highest aspect ratio was explained by its porosity and optical characteristics.

ZnO nanorod, Optical constant, Photocatalytic Activity