Application And Passivation Mechanism Study Of Organometal Salts In The Interface Of Perovskite Solar Cells

Perovskite solar cells（PSCs）based on SnO₂ electron transport layer have a number of advantages,such as low temperature of fabrication,simple preparation method process and low cost.In recent years,the power conversion efficiency（PCE）of PSCs on the SnO₂ substrate has been further improved.However,there are often many defects at the interface between the perovskite layer and the electron transport layer（ETL）,influencing the PCE and the long-term stability of the PSCs.In this dissertation,taking the PSC based on SnO₂ as the research object,we modify interface of ETL/perovskite with organometallic salt material,resulting in promoting the charge transmission performance,effectively boosting power conversion efficiency and improving long-term stability.Finally,the mechanism of action of the organometallic salt on the PSCs is comprehensively summarized,and the main research contents are as follows:A trace amount of Ethylenediamine tetraacetic acid disodium magnesium salt（EDTADM）was deposited onto the SnO₂ ETLs.The carboxyl and trialkylamine functionality and Mg²⁺/Na⁺cations of in EDTADM additive cause less defective and highly conductive SnO₂ ETLs,which offers distinguished platforms for the growth of perovskite layers with high-quality crystallinity and compact morphologies to promote the interfacial charge transfer.The incorporation of EDTADM leads to the notable passivation through establishing coordination interactions with Sn⁴⁺or Pb²⁺in SnO₂and perovskite films,respectively.Moreover,Mg²⁺/Na⁺cations of the additive can partly get into the absorber through heat diffusion to suppress the imperfection states,further boosting the photovoltaic performance of the PSC devices.Such simultaneous optimization for SnO₂ ETLs,perovskites and their interface allows the fulfillment of high power conversion efficiency（PCE）of 20.81%with decreased hysteresis and enhanced stability for EDTADM-containing PSCs.Unsealed PSCs with EDTADM displays better ambient stability.They maintain 68%of their original PCE after being stored under ambient condition（25-30℃,50-65%relative humidity）for 1300 h,while the PCE of the reference devices degrades to 28%after the aging.The introduction of disodium chloride phosphate（CH₂Cl₂Na₂O₆P₂,DCP）at the ETL/perovskite interface improves the absorption capacity of perovskite films and passivates the defects in the perovskite layer.With the modification of DCP,the carrier transportation is more efficiently,suppressing the hysteresis effect,improving the stability of the device in humid air.Deposited DCP on ETL,the PCE of PSC have increased from 16.64%to 17.74%.After storing in humid air,the modified device can still maintain 69%of the original efficiency after 600h,while the reference device only maintains 51%of the initial efficiency.After being modified by DCP,the PCE and long-term stability of the PSC have been efficiently improved.