Theoretical Study On Thermoelectric Properties Of Boron Nitride Nano-Films

For higher temperature range applications,thermoelectric devices require inorganic materials.One of the main problems of commercial thermoelectric devices manufactured using bulk inorganic materials is their poor mechanical flexibility.Therefore,it is a promising choice to prepare inorganic materials in the form of thin films based on thin-film thermoelectricity of low-dimensional materials.At present,the BNNR thermoelectric performance literature has not had a clear quantitative result on the research with BNNR thermoelectricity.For research work using different methods,due to different data sources and different processing methods,the final results obtained are very different.The thermoelectric figure of merit of BNNR cannot give a more accurate result.Research on the thermoelectric properties of quasi one-dimensional nanomaterials such as BNNR still needs follow-up research work to supplement the current deficiencies.In this paper,combined with the actual preparation of samples of boron nitride nanoribbons in the laboratory,a variety of supercell models of boron nitride nanoribbons were established.The first-principles simulation analysis software is used to theoretically study its thermoelectric performance,which provides a reference for the development of nano-scale thermoelectric devices.Based on first-principles analysis,this study analyzed the thermoelectric transport performance of the BNNR with different chirality of double-layer edge hydrogenation.The results show that ABNNR has a higher thermoelectric figure of merit,and can be used to generate electricity at a specific temperature difference by making nano-films of different specifications.Compared with the bulk material,it is a relatively good flexible thermoelectric material.The ZT value of ZBNNR has no great advantage over bulk materials,but its chemical potential has a wide response range.P-type thermoelectric materials can be prepared by carbon and oxygen doping modification,and mixed with ABNNR to make better thermoelectric films.The thermal conductivity of the two types of nanoribbons increases with increasing temperature,and the trend of change in different environments is basically the same.The thermal conductivity of ZBNNR is an order of magnitude higher than that of ABNNR.The ZT values of the double-layer 10 ABNNR at 100 K,300K,and 600 K all exceed 10 and reach a maximum of 15.13.The ZT value is 1.85 under the environment of high temperature 800 K.Overall,the range suitable for thermoelectricity is relatively narrow,only 0.03Ry(0.378 e V),but it has better adaptability in terms of working environment temperature and is basically available in full temperature range.The double-layer 13 ZBNNR has a low ZT peak of only 0.8,which is not suitable for thermoelectric power generation.At the same time,it can be seen that there is basically no thermoelectric power generation capacity in a 100 K environment.However,it has 6 sets of peaks,which means a relatively wide thermoelectric working range and great potential for development.