Theoretical Study On Stable And Efficient Photovoltaic Materials Based On Diamino Organic Inorganic Hybrid Halide Perovskite And Its Superlattice Structure

In recent years,organic-inorganic hybrid halide perovskite has attracted extensive attention due to its excellent photoelectric properties,and has become the most promising material for the development of next generation solar cells.ABX₃type hybrid perovskite,such as CH₃NH₃Pb I₃(MAPb I₃)and CH(NH₂)₂Pb I₃(FAPb I₃),has been regarded as an excellent photovoltaic material due to its high carrier mobility,high absorption coefficient,high open circuit voltage,suitable band gap and low carrier recombination rate.However,the stability of these organic-inorganic hybrid halide perovskite materials represented by MAPb I₃and FAPb I₃is the most urgent challenge.Based on its special octahedral structure,its internal factors such as electron transfer,ion transfer,interface reaction and other external factors such as humidity,temperature,oxidant may have an important impact on the stability of perovskite materials,which makes it show low performance in the environment.The thermal stability and chemical stability of the device ultimately affect the durability of the device.In this paper,the stability of materials is an important issue to start with the calculation research,the introduction of diamino cations to solve the hot issue of low stability of monoamino perovskite materials,and through the combination of conventional perovskite materials to form perovskite superlattice structure,the stability is improved and the band gap is adjustable,further improving the photoelectric performance.The specific work is as follows:Firstly,the structure,electronic properties,transport properties and optical properties of three-dimensional diamino perovskite materials PDAPb I₄and DABPb I₄composed of diaminocations PDA and DAB were studied.In order to compare and verify whether the introduction of diamino organic cation PDA and DAB can improve the carrier mobility in perovskite materials,we also calculated the geometric structure,electronic properties and optical properties of(PT)₂Pb I₄and(MBA)₂Pb I₄two-dimensional single amino perovskite materials composed of single amino cation molecule PT and MBA with the same chain length.The results show that the organic diaminocations enhance the coupling effect between the inorganic layers of Pb-I,and provide a good channel for carrier migration,especially in the inorganic layer of Pb-I.In addition,the organic diaminocations three-dimensional perovskite materials have excellent optical absorption properties in the solar irradiation range,which will help to design and synthesize more effective and stable organic inorganic perovskite photovoltaic devices in the future.Based on the calculated stability and excellent carrier transport properties of diamino organic cationic perovskite,combined with the excellent properties of conventional perovskite,we constructed the superlattice structure of perovskite.Based on the excellent properties of perovskite,the stability of the materials is improved.Therefore,eight kinds of organic inorganic halide perovskite superlattice materials,namely(Cs Pb I₃)_n/PDAPb I₄and(MAPb I₃)_n/PDAPb I₄,of which n is the number of conventional perovskite materials,and the number of layers is one to four.The geometric structure,formation energy,thermodynamic stability,electronic structure,exciton properties,optical absorption properties and power conversion efficiency of these superlattices were studied.These results show that it is feasible to obtain these perovskite superlattices and their practical applications.The introduction of functional diaminocationic PDA into the superlattice structure can further improve the stability of organic-inorganic hybrid perovskite materials,which is conducive to the design and synthesis of more efficient and stable organic-inorganic hybrid perovskite superlattice materials for application in the future photoelectric field.