Nanorods | Image Resource : rsc.org
Nanorods are one of the findings of the present nanotechnology era. Their dimensions usually vary from 1-100 nanometers and they can be synthesised either using semiconductors or metals. Shape controlling action is performed by a set of ligands which also provide strength to the arrangement. Nanorods are synthesised by direct chemical synthesis. The nanorods can be grown at various rates and result in a large chain of such rods.
The orientation with which the electric field is applied plays a vital role in which these rods are reflected and thus can be employed in display technologies. Semiconductor nanorods can be used to harvest energy and emit light in a more efficient way. The LEDs we use also consist of a large number of nanorods. A research has shown that nanorods can even be used as new sources of UV radiation.
Nano rods are very small in size in the range of nanometers and thus are the morphology of objects in the nanoscale. The length to the width ratio of nanorods is 3:5. There are various kinds of nanorods like gold rods, zinc nanorods and cation exchange nanorods.
The nanorods of Zinc Oxide are also referred to as nanowires and have a small band gap of 3.37 eV. These are the electrodes that are of immense importance and are the most common form of rods of nano size. They have been used for fabrication of LEDs, photoelectric conductors and other nano-electronic devices. Vapor phase growing is the most common form of obtaining a zinc nanorod. It is scientifically known as a V-L-S process namely Vapor Liquid Solid process. This method has been in use for decades and is still the most efficient means of synthesising the nanorods of this kind.
However, for synthesising gold nanorods, another growth process namely seed-mediated growth method is used. By this method, long golden nanorods of aspect ratio of up to 25 can be obtained which can be very valuable in forming some very handy substances.
Also there is Cation exchange process which is also very promising. This method conserves the shape of the nanorod and favorable shapes can be obtained. It is also faster in comparison to the other two techniques due to high surface area. A high chain of nanorods in its sustainable form can also be obtained but they cannot be produced by wet-chemical synthesis.
The first and foremost application of nanorods is in display technologies and it has redefined the way we view screens.
In the field of science and technology, nanorods are used in micro-electro-mechanical systems which are very handy and effective in use.
Nanorods also have several therapeutic applications and are employed in various advanced medical applications.
Apparently, nanorods are also used in treatment of cancer in initial stages. Nanorods generate heat when excited in the Infrared region and thus are ingested into the human body with tumor targeting motifs. Thus, when nanorods are heated in infrared region, they heat up and destroy the cancerous cells thus helping in tumor reduction.
Nanorods are usually small in size but can be increased in aspect ratio through various other methods and serve various vital functions. They are a technology of tomorrow and can possibly decrease the size of our devices and have future implications in advanced medical sciences. The research in this field is more than ever and it is further evolving as the best is yet to come.