Challenges faced by scientist with the existing rectifiers:
From the past many years, research is mainly focussed on harvesting and converting ambient energy into usable electrical energy. With the help of rectifier devices, these electromagnetic waves from their oscillating current are converted into direct current. The limitation with these rectifiers is it has the ability to process low-frequency waves such as radio waves and is not able to accommodate the terahertz range. A few experimental technologies have been designed to convert such high-frequency Hz into DC but only at an ultracold temperature which is practically difficult to implement.
A probable solution overcome the challenge faced:
A recent research study at MIT expanded Graphene’s horizon in harnessing terahertz radiations which might enable self-powering implants, cellphones, and other portable electronics.
Terahertz waves are electromagnetic waves whose frequencies range between microwave and infrared light. These high-frequency radiation waves are pervasive as they are produced by almost anything that registers a temperature. To harness their concentrated power which could potentially serve as an alternate energy source a heterojunction device incorporating Graphene and Boron Nitride could be employed. The combination of Graphene with Boron Nitride will direct the electrons in Graphene to skew their motion in one direction resulting in more concentrated direct current. In this, material own electrons at the quantum mechanical level will be induced in one direction to steer incoming T waves to higher magnitude DC.
Graphene's attributes and it's usefulness:
Due to superior electrical conductivity, high surface area, and a broad electrochemical window, Graphene has proven to be very advantageous for energy harvesting and storage applications.
Graphene, a unique two‐dimensional carbon material with exceptional properties as high electrical and thermal conductivity, zero bandgap, high optical transmittance and superior mechanical performance than steel, is often regarded as the material of the twenty‐first century. A great focus is being added to graphene in all scientific fields, such as physics, chemistry, and even medicine. Nanocomposites, dispersions, and films that include graphene in a polymer matrix are the trending topic of recent research studies.
Naturally, Graphene possesses inversion symmetry meaning that incoming energy would scatter electrons in all directions. Therefore, to direct this asymmetric flow of electrons in response to incoming energy n-type material having similar honeycomb lattice Boron Nitride could be used. The heterojunction placement of Graphene and Boron Nitride would enable skew scattering of electrons, in which a major proportion of electrons skew their motion in one direction. Apart from BN, to generate DC the level of impurities in Graphene should be minimal. If too many impurities exist in Graphene, it would obstruct the path of electron motion, resulting in electron clouds to scatter in all directions.
It is also found that the stronger the incoming Tetrahertz energy, the more it increases the ability of the device to produce DC. If Terahertz waves are concentrated before it enters the device, it would lead to higher magnitude DC. To build this setup, researchers drew up a terahertz rectifier that consists of a small square of Graphene that is aligned with a layer of BN and is sandwiched within an antenna that would collect and concentrate ambient terahertz radiation, boosting its signal enough to convert it into a DC.
Possible applications of proposed device:
If the proposed device works at room temperature, It could be used for many practical applications.such as wireless power implants in a patient body, without requiring surgery to change implant batteries. Such devices could also convert ambient wi-fi signals to charge up personal electronics such as laptops and cellphones.