Study Of Performance Enhancement Of Perovskite Solar Cells By Pr³⁺ Ion Doping And 2-FINA Interfacial Modification

As the information age approached,resource scarcity and environmental pollution problems inevitably arouse.The rational use of solar power generation has received great attention from researchers.Among them,perovskite solar cells(PSCs)have achieved remarkable progress since their inception in 2009.Due to its long carrier diffusion length,tunable band gap and high optical absorption coefficient,its photoelectric conversion efficiency has exceeded 25.7%.Bulk and interface defects will inevitably occur during the crystallization process of the perovskite light absorber film,due to its multi-crystalline nature.These defects would inherit lattice instability and act as centers of the non-radioactive recombination.Such problems would limit the photo conversion efficiency(PCE)and sabotage the stability of the PCSs devices,dramatically hinder the industrialization of the PSCs.To tackle these problems and fabricate PSCs with high efficiency and stability has become the key research point in the field.In this work,we successfully passivated the defects caused by uncoordinated lead ions and pinholes on the surface and grain boundaries of perovskite films by ion doping and interface modification strategies and suppressed the carrier nonradiative recombination.As a result,perovskite solar cells with high efficiency were successfully obtained and the long-term stability of the PSCs were significantly improved.The research is summarized as follows:1)Praseodymium ion(Pr3+)dopant was introduced into the tri-cation perovskite as ion source.The introduction of the Pr3+dopant effectively controlled the perovskite crystallization process and inhibited the formation of the by-product lead iodide(PbI2);and the incorporation of Pr3+could inhibit the excessive growth of grains,hinder the collapse of the lattice,and stabilize the perovskite lattice.With optimized the concentration of dopant and doping techniques,PSCs based on Pr3+doping achieved 18.56%PCE and improved stability.2)Perovskite films were treated with 2-fluoroisonicotinic acid(2-FINA)as a passivation agent.The carboxylic acid group and pyridine group contained in 2FINA generate Lewis acid-base interaction with the uncoordinated lead atoms,effectively passivated defects at the interface region and prohibited non-radiative recombination.With optimized passivation conditions,the efficiency of PSCs was improved to 20.68%,and the stability against moisture was dramatically increased.