Enhancing Efficiency And Stability Of Perovskite Solar Cells Using Interfacial Modification Technique

At present,the photoelectric conversion efficiency（PCE）of perovskite solar cells（PSCs）using organic-inorganic hybrid perovskite materials as light-absorbing layers has reached 25.2%.Perovskite materials have the advantages of high absorption coefficient,high carrier mobility,small exciton binding energy and solution processing.However,the cell efficiency and stability of perovskite solar cells need to be further improved to realize industrial application.This paper employed titanium oxide-based and nickel oxide-based perovskite solar cells as the research object,using interface modification techniques to optimize the structure and performance of the device,improve crystallization of perovskite films,carrier transport and collection abilities,which can effectively enhance the efficiency and stability of PSCs.The main research contents are as follows:1.A p-type poly（9-vinylcarbazole）（PVC）was inserted into the interface between perovskite and mesoporous TiO₂ electron transport layers.Using PVC large band-gap and hydrophobicity and its passivation of N atoms,PVC modified the interface of TiO₂/perovskite layers,which can improve crystallization and densification of perovskite layer,passivate TiO₂/perovskite interface,improve interface hydrophobicity,block hole accumulation at the interface of TiO₂/perovskite layers,reduce carrier recombination and improve carrier transport and extraction abilities.Therefore,Therefore,PSCs with PVC modified TiO₂/perovskite interface exhibited a power conversion efficiency（PCE）of 19.02%,which is remarkably higher than that（16.09%）of the reference cells.Furthermore,PSCs without and with PVC modification respectively retained 20%and 55%of the initial PCE values aging for 30 days at the relative humidity 15%in air without encapsulation.The results indicate that PVC modified TiO₂/perovskite interface can improve PCE and stability of PSCs.2.A ferrocene derivative ferrocenecarboxylic acid（FDA）was added to chlorobenzene as an anti-solvent for the preparation of perovskite films in a one-step process to participate in the growth process of perovskite films.The FDA-modified perovskite films have better crystallinity and higher carrier transport ability.The efficiency of FDA modified PSCs has been increased to 18.34%from 17.12%of reference PSCs.The FDA-modified perovskite film maintains better light absorption capacity under 10 h UV lamp irradiation,indicating better anti-UV resistance.In addition,aging for 30 days at 25℃and a relative humidity of 15%,the unencapsulated PSCs with and without PVC modification retains 78%and 60%of the initial PCEs,indicating that PVC modified perovskite layer help to improve moisture resistance of PSCs.