The Research On Thermoelectric Mechanism Of Graphene Nanoribbon Based On DNA Base And Side Oxidation Modulation

The study shows that cars release 40 percent of the waste heat from fuel combustion into the natural environment through exhaust pipes.In 2014,China alone had 146 million civilian vehicles,emitting heat equivalent to the energy released by burning 120 million tons of fuel,or about 25 percent of China's annual fuel consumption.It can be seen that human energy is mainly wasted in the form of waste heat,which leads to social energy crisis,environmental pollution,climate change and other problems increasingly prominent.Therefore,the recycling of waste heat is of great significance to the energy conservation and emission reduction of China and even the world,and the development of green renewable energy is imperative.Many researchers have been researching and developing new sources of clean energy,such as wind,water and solar energy.This has become a new trend in the research circle,but a difficult problem has been facing many researchers,how to improve energy efficiency and reduce energy loss as much as possible.Now,there is a material that can realize thermoelectric conversion,namely thermoelectric material.It is a kind of green energy material that can convert heat and electricity without any external force.People can use waste heat in production and life to generate electricity or realize accurate heat transport under the condition of applying bias voltage,which will be widely used in temperature difference battery power supply,microsystem chip temperature control refrigeration and other fields.The research mainly includes two aspects.First,we studied the thermoelectric properties and applications of A,C,T,G base modulated serrated graphene nanoripetre(ZGNR-A,ZGNR-C,ZGNR-T,ZGNR-G)by combining non-equilibrium green's function with first principles.The results show that,in 3-ZGNR-i,I3-ZGNR>I3-ZGNR-A>I3-ZGNR-C>I3-ZGNR-T>I3-ZGNR-G;When the bias voltage is>0.6v,the current value of 4-ZGNR-i(i =A,C,T)is significantly higher than that of ideal 4-ZGNR.Different from the electron transport properties,the phonon scattering intensity of ZGNRs modulated by all DNA bases was significantly enhanced,resulting in a decrease in thermal conductivity.Due to the decrease of thermal conductivity and the drastic fluctuation of electron transmission,the thermoelectric quality factor ZT value of ZGNRs modulated by DNA base was significantly increased.These results may have great potential applications in the next generation of electronic circuits,such as designing switches,memory and thermoelectric devices.Secondly,the thermoelectric properties of edge-state oxidized graphene nanoribbons are studied by combining the non-equilibrium green's function with the first principle.The thermal and electrical transport properties of ZGNR-O and ZGNR-OH are analyzed.The results show that the thermal transport of ZGNR-O and ZGNR-OH is significantly inhibited due to the influence of the scattering region,and the transmission probability varies with the changes of the hydroxyl group at the edge of ZGNRs and the oxygen-containing cardinal order and position.The electron transport of ZGNR-O and ZGNR-OH in the positive energy region is almost unaffected.In the negative energy region,the ZGNR-O electron transmission fluctuates violently and presents complex peak-valley structure,which leads to the increase of seebeck coefficient.The results confirmed that covalent coupling of oxygen-containing group(-O-)and ZGNR could significantly improve the thermoelectric performance index ZT value of GNRs,but the covalent coupling of hydroxyl group(-OH-)and ZGNR could not improve its thermoelectric performance.