Quick single-step mechanosynthesis of ZnO nanorods and their optical characterization: milling time dependence

Abstract

We report on the growth of ZnO nanorods (NRs) by a quick single-step mechanochemical process and investigated the milling time dependence on the structural and optical properties of the ZnO NRs. Mechanochemical reactions are carried out in a planetary ball mill for the time durations ranging from 30 min to 5 h. XRD and TEM studies revealed wurtzite structure of the as-grown ZnO NRs with length of several hundreds of nanometers to few micrometers after 30 min of reaction. Average diameter of the as-grown ZnO NRs decreases from 40 to 15 nm with increasing reaction time. Micro-Raman spectra show redshift in the characteristic Raman modes, indicating presence of milling induced strain. As-grown NRs show blueshift in the excitonic absorption peak with increasing milling time due to decrease in size and induced strain. Room temperature photoluminescence (PL) spectra show strong band-edge related UV emission and other three major emission peaks, two in the UV-blue region and one at the visible region. Post-growth annealing of the asgrown ZnO NRs completely eliminates the defect related visible PL band. Low-temperature PL studies show an additional sharp peak related to donor-bound excitonic transition, revealing the n-type nature of the as-grown NRs.

The role of NaOH content, grinding time, and drying temperature in controlling the shape and size of nano ZnO synthesized by a green chemistry approach

“…The results revealed no significant effect on the shape or particle size of nano ZnO. Regarding the grinding time's effect; the present results are in contrast to results obtained by Dhara and Giri [73] and Salah et al [74] that revealed the decrease in the particle size by increasing the milling reaction time. Elucidation of this contrast can be based on one of the two following assumptions; the first assumption is that long-time grinding produces smaller particles with higher surface areas, the high surfaced particles tend to agglomerate producing larger ones [75] due to Van der Waals or other attractive forces.…”

Charging gold nanoparticles in ZnO by electric fields

“…The peak at 377 nm originates from excitonic absorption [38]. This ZnO peak is much stronger in the presence of gold clusters, which is attributed to a possible enhancement of the ZnO UV peak caused by plasmonic local field enhancement [21].…”

ZnO Nanorods Arrays and Heterostructures for the High Sensitive UV Photodetection

“…We have synthesized ZnO NRs of various diameters by mechanosynthesis method at room temperature for reaction time as short as 30 minutes (Chakraborty et al, 2011;Dhara & Giri, 2011b). For the growth of ZnO NRs, mechanochemical reactions were carried out in a planetary ball-milling apparatus.…”