Study On Additive Engineering To Improve The Performance Of Quasi-Two-Dimensional And Sn-Pb Mixed Three Dimensional Perovskite Solar Cells

Organic-inorganic hybrid perovskite solar cells（PSCs）are widely regarded as the most promising photovoltaic technology due to their excellent photoelectric performance,simple preparation method,and low cost.However,the poor stability of organic-inorganic hybrid PSCs hampers their commercial application.Quasi-two dimensional（Q-2D）perovskite materials have significantly enhanced device stability owing to the presence of a hydrophobic organic spacer layer.However,the random arrangement of different n-phase perovskites in Q-2D perovskites impedes carrier transport,leading to lower optoelectronic performance.Sn-Pb mixed 3D perovskite materials,with a bandgap as low as 1.2 e V,are considered the most ideal bottom light absorbing material in tandem solar cells,and have been extensively studied.Nevertheless,Sn-Pb mixed 3D perovskite suffers from drawbacks such as the easy oxidation of Sn²⁺and a high density of defect states,which limit the development of tandem solar cells.Additive engineering is the principal method to enhance the photoelectric performance and stability of PSCs.In this paper,organic macromolecular ammonium salts are utilized as additives to improve the photoelectric performance and stability of Q-2D and Sn-Pb mixed three-dimensional PSCs.The specific research contents are as follows:（1）We investigated the effects of the 4-Fluorophenethylamine Hydroiodide（F-PEAI）additive on the properties of（BA）₂MA₃Pb₄I₁₃（n=4）based Q-2D PSCs and perovskite films.Our study found that F-PEAI can slow down the crystallization of Q-2D perovskite and form dense and hole-free perovskite films.Moreover,F-PEAI can improve the arrangement of different n-phase perovskites in Q-2D perovskites,reduce carrier recombination loss in the film,and improve carrier extraction efficiency.The PCE of（BA）₂MA₃Pb₄I₁₃ based Q-2D PSCs prepared with F-PEAI additive was improved from 10.56%to 16.06%.Additionally,the air stability of Q-2D PSCs after using F-PEAI additive is greatly enhanced.The results of this research provide an effective strategy for the preparation of high-quality Q-2D perovskite films using organic macromolecular ammonium salt additives.（2）We explored the effect of the 4-Fluorobenzylamine Hydroiodide（F-BZAI）additive on the properties of（MAPb I₃）_0.4（FASn I₃）_0.6 based Sn-Pb mixed three-dimensional PSCs and perovskite thin films.The study found that F-BZAI can form 2D phase perovskite in the Sn-Pb mixed 3D perovskite film,with these 2D phase perovskites mainly distributed at the grain boundary.This can passivate the grain boundary and inhibit the oxidation of Sn²⁺,thereby reducing nonradiative recombination in tin-lead hybrid 3D PSCs.Moreover,F-BZAI can effectively enhance the PCE of PSCs from 18.20%to 20.21%,and the air stability of the device is also greatly improved.