Study On The Performance Of Graphdiyne Modulated Perovskite Solar Cells

Organic-inorganic hybrid perovskite shows great application prospects in the field of photoelectric energy conversion because of their high absorption coefficient,adjustable optical band gap and long charge diffusion distance,which are considered as the most competitive candidates for the next generation of solar cells.However,in the whole life cycle from growth to service,perovskite devices are faced with bottlenecks such as interface defects,ion migration,energy band mismatch and lead leakage,which seriously restrict the service performance of photovoltaic devices and hinder their further development and application.Graphdiyne and its derivatives possess a stable highly π-conjugated structure,and abundant carbon chemical bonds provide various paths and sites for chemical modification,which is expected to effectively regulate the generation,transport and recombination behavior of photogenerated carriers and ion migration behavior,and further realize the comprehensive optimization of perovskite solar cells.This article focuses on the design and construction of high-efficiency and stable perovskite solar cells.On the basis of controllable preparation of high-quality graphdiyne and its derivatives,the performance and stability of perovskite solar cells are greatly improved from the perspectives of defect passivation,ion migration,band alignment and lead leakage suppression.Furthermore,three strategies were proposed to optimize perovskite including pyridinic nitrogen doped graphdiyne for perovskite interface optimization,fluorine doped graphdiyne gradient distribution in perovskite and graphdiyne regulating carbon electrode for lead fixation.The specific research contents are as follows:A variety of graphdiyne monomers were adopted for Glaser coupling reaction,and high-quality graphdiyne,nitrogen-doped graphdiyne and fluorine-doped graphdiyne materials were successfully synthesized via bottom-to-top procedure by adjusting the parameters such as catalyst type and reaction temperature.And the controllable preparation of small-sized graphdiyne nano-sheets was realized through intensively ultra-sonic treatment and other means.Pyridinic nitrogen doped graphdiyne was adopted to optimize perovskite interface.On the basis of greatly delaying the crystallization rate of perovskite to obtain high-quality perovskite crystals,the passivation effect and mechanism of pyridinic nitrogen functional groups on interface defects are expounded.Additionally,the spatial confinement coupling with electrostatic repulsion effect originated from the intrinsic 2D structure of pyridinic nitrogen doped graphdiyne,has been identified to deal with the halide ion migration behavior.Finally,trap state density within perovskite is reduced by approximately an order of magnitude and ion migration is significantly suppressed,and the photoelectric conversion efficiency of perovskite solar cells is greatly improved to 22.38%.Fluorine doped graphdiyne was gradiently introduced into perovskite film,and energy band gradient arrangement within perovskite film is realized.The regulation mechanism of fluorine doped graphdiyne distribution on the energy level of perovskite was systematically explored,and the mechanism of fluorine doped graphdiyne in promoting the carrier migration of perovskite was clarified.Compared with the reference sample,the photoelectric conversion efficiency of the optimized perovskite solar cell was improved by 14.7%.In addition,fluorinedoped graphdiyne further strengthened the hydrophobicity of perovskite,and effectively improved the service stability of perovskite devices.Graphdiyne was introduced to carbon electrode for lead fixation.The regulation effect of graphdiyne on lead leakage suppression was thoroughly revealed,and the adsorption mechanism as well as adsorption sites for lead ion were explored.Besides,the passivation effect of graphdiyne on perovskite interface defects and carrier transport mechanism were intensively investigated.Finally,more than 80%of lead leakage was effectively suppressed because of the chelation effect between lead ion and graphdiyne.At the same time,the hole mobility of the optimized device is greatly improved to 9 times compared with the original sample.