Study On The Photoelectric Properties Regulation Of Perovskite Films By Nitrogen-containing Organic Additives And Their Photovoltaic Performance

Perovskite solar cells have received more attention from scholars all over the world due to their high efficiency,low cost,lightness,flexibility,and solution fabrication.At present,its highest power conversion efficiency has exceeded 25%.To further enhance the performance of perovskite solar cells,the key problem is the preparation of high-quality,low-defect perovskite films.The introduction of organic additives is a common and effective means to regulate the growth of perovskite films and passivate their surface/interface defects.This paper mainly focuses on the organic additives used in perovskite,and conducts in-depth research on the regulation of perovskite film growth and defect passivation.It is proposed to use non-volatile organic additives with high melting point and high boiling point to effectively passivate the internal defects while regulating the growth of perovskite thin films,and finally prepare perovskite solar cells with an efficiency>21%.At the same time,it is proposed to use organic-lead iodide radical additive to achieve effective passivation of perovskite internal defects while ensuring its charge transport ability,and prepare perovskite solar cells with an efficiency>22%.The main contents are as follows:1.Pyrazine-based organic additives are used to simultaneously regulate the growth and defect passivation of perovskite films.Using pyrazine nitrogen-containing organic additives that are solid at room temperature,low melting point,and high boiling point,the additives can be melted into a liquid with high fluidity during the heating process,thereby dynamically regulating the growth of perovskite films.The boiling point of the crystallization temperature can ensure its final retention in the film,combined with the strong interaction between the nitrogen atoms in its molecule and the uncoordinated Pb²⁺ions in the perovskite film.The iodine vacancy defects at the bulk and interface of the perovskite thin film are effectively passivated,suppressing nonradiative recombination in the cell,and finally achieving a high efficiency of over 21%.2.The use of lead iodide in the form of free radicals can passivate defects while ensuring efficient charge transport.Considering the generally poor conductivity of organics,commonly used organic additives may cause charge transport problems when passivating perovskite defects,limiting the improvement of battery performance.In response to this,we adopted N,N,N',N'-tetramethylbenzidine(TMB)additive,which utilizes the interaction between TMB and lead iodide to form free radicals(TMB-Pb I₂).The high conductivity of the TMB-Pb I₂ radical enables it to passivate film defects while ensuring efficient charge transport.Based on this,we achieved a reverse perovskite solar cell with an efficiency of22.63%.In addition,the device exhibits good stability,maintaining 95%of the initial efficiency under continuous heating at 85°C for 600 hours.