Study On The Performance Of Graphdiyne Modulated Photoelectric Energy Conversion Devices

The efficient use of solar energy is an important technical approach to solve the current energy and environmental problems of human society,and it is also the key to our country’s early realization of "carbon peak" and fulfillment of our“carbon neutral" promise.Photoelectrochemical water splitting cells and perovskite photovoltaic cells can convert solar energy into hydrogen energy and electric energy,and are currently important means for photoelectric energy conversion.However.silicon-based photoelectrochemical electrodes still suffer from low photovoltage.poor charge transport performance.and slow oxygen evolution kinetics;perovskite photovoltaic cells still have problems such as charge transport mismatch,difficulty in preparing high-quality perovskite films,and poor stability.Graphdiyne is a two-dimensional planar structure of all-carbon macromolecules formed by conjugated connection of benzene rings with 1,3-diacetylene bonds,with periodic distribution of acetylene bonds,benzene rings and triangular pores.Its rich carbon chemical bonds,high π-conjugated structure,natural intrinsic band gap,excellent thermal stability,and ultra-high electron mobility are expected to provide important ideas for solving various problems in photovoltaic energy conversion devices.Based on this,this dissertation focuses on graphdiyne materials and applies graphdiyne to photoelectrochemical water splitting batteries,organic-inorganic hybrid perovskite photovoltaic cells,and all-inorganic perovskite photovoltaic cells.From the perspectives of the controllable preparation of graphdiyne micro-nano structures,the induced growth of perovskite materials,surface and interface engineering,the design and construction of photoelectric conversion devices,and the optimization and regulation of performance,the improvement in photoelectric conversion efficiency and stability had been achieved.The specific research content is as follows:(1)By adjusting the reaction conditions of graphdiyne synthesis,the path of the cross-linking coupling reaction of graphdiyne monomers was changed.By using the Glaser coupling reaction,a large number of graphdiyne powders were prepared on the surface of copper foil:and graphdiyne nanoparticles with a good dispersion of about 5 nm were obtained by means of strong ultrasonication.Graphdiyne nanowall arrays were prepared on different substrates such as copper foil.carbon cloth,and pyramidal silicon through Glaser-Hay coupling reaction.(2)A silicon heterojunction/graphdiyne/nickel oxide photoanode structure was designed and constructed.The effect of graphdiyne nanowall arrays on the charge transport and mass transfer of the photoanode structure was studied,and the mechanism of the interaction between graphdiyne and nickel oxide on improving the photoelectrochemical performance of the photoanode structure was explored,the working principle of the photoanode was also analyzed.The silicon photoanode sample achieved a minimum turn-on potential of 1.082 V(vs.RHE)and a maximum saturation current density of 39.1 mA/cm2,and the minimum Tafel slope reached 113 mV/dec.(3)The preparation technology for graphdiyne-doped SnO2 electron transport layer was developed,and low-temperature planar hybrid perovskite solar cells were constructed.The effects of graphdiyne on the visible light absorption,electron mobility and energy band position of tin oxide had been systematically studied.The graphdiyne-doped tin oxide electron transport layer has the effect of inducing growth of perovskite materials and reducing defects.With the help of density functional theory,the mechanism of graphdiyne on improving the electrical transport performance of tin oxide and passivating the defects of perovskite was clarified.The optimal power conversion efficiency of hybrid perovskite solar cells increased by ten percent,and 93%of the initial efficiency can be maintained for unencapsulated devices after being placed under ambient atmospheric conditions for 1000 hours.(4)The preparation technology for graphdiyne to regulate the growth of CsPbI3 all-inorganic perovskite film was developed,and all-inorganic perovskite solar cells were constructed.The effects of graphdiyne doping on the improvement of the crystalline quality and surface morphology of all-inorganic perovskite films,as well as the regulation of visible light absorption,energy band structure and phase stability were studied.The graphdiyne-doped CsPbI3 all-inorganic perovskite exhibits significantly enhanced phase stability under ambient environment conditions,and the stability of solar cells based on the above-mentioned all-inorganic perovskite has also been improved markedly.In this dissertation.toward the construction of high-performance photoelectric energy conversion devices and give full play to the intrinsic characteristics of graphdiyne materials.the optimization and improvement in photoelectric conversion efficiency and stability in photovoltaic materials based photoelectrochemical water splitting and solar cells devices were realized,and the mechanism of improving the photoelectric performance of different photoelectric energy conversion devices was in-depth studied.Based on this research,a further understanding of the performance of graphdiyne and its composite photovoltaic materials is highly expected,which will provide theoretical basis and technical reserves for graphdiyne and its derivatives to further exert its advantages in the field of photovoltaic energy conversion.