Cation Engineering for Effective Defect Passivation to Improve Efficiency and Stability of FA_0.5MA_0.5PbI₃Perovskite Solar Cells

Abstract

Large organic cations have been widely employed to passivate defects in perovskite solar cells (PSCs). In this research, we study how double ions influence PSC developments. Four additives, namely, BAI, BACl, PEAI, and PEACl, were introduced into the precursor solution during the hybrid PSC preparation, and it is found that they not only improve the crystallization of the perovskite films but also passivate the surface and grain boundary defects, leading to improved PSC performance. BACl is found to be the best among this group of additives, giving the highest solar cell efficiency and the best stability. This work provides insights and guidelines as to how amine additives influence perovskite film formation as well as device performance, which is badly needed for PSC advancement.

Effect of Organic Chloride Additives on the Photovoltaic Performance of MA‐Free Cs0.1FA0.9PbI3 Perovskite Solar Cells

“…As a result, BA and PA could only occupy the surface or grain boundary position in crystallized films. [31,36,37] As for EA, one would expect lattice insertion by FA substitution due to similar ionic size (Table S1, Supporting Information), if present in final films after thermal annealing, but the absence of lattice variation detectable via XRD test indicated that most EACl was removed during the annealing at 140 °C via evaporation, consistent with the previous report on EACl-engineered MAPbI 3 films. [38,39] Based on the morphological and XRD results presented above, we proposed the crystal growth mechanism for large and favorably oriented grains in films with additives (Figure 3e,f ).…”

“…This study revealed that both cation and anion from additives positively influence the performance, with organic cations, i.e., FA and MA, enabling higher performance than inorganic cations Cs + and Rb + , [ 29 ] due to their strong ability to effectively passivate bulk and grain boundary defects. [ 30–32 ]…”

“…This study revealed that both cation and anion from additives positively influence the performance, with organic cations, i.e., FA and MA, enabling higher performance than inorganic cations Cs þ and Rb þ , [29] due to their strong ability to effectively passivate bulk and grain boundary defects. [30][31][32] Generally, Cl additives are known to tune the film formation for perovskites, leading to improved morphology and high crystallinity, and consequently solar cell performance in most cases. [33] But the analysis of published literature showed that there are few studies dedicated to gaining a deeper insight into the underlying mechanisms behind the properties improvements using organic additives besides the popular MACl additive which should be avoided due to possible incorporation of MA into the host perovskite lattice capable of slightly blueshifting the bandgap in addition to its propensity to easily undergo thermal decomposition.…”

Multistrategy Preparation of Efficient and Stable Environment-Friendly Lead-Based Perovskite Solar Cells

“…The quality of the perovskite film plays a key role in preparing the PSCs with high PCE. ,, As yet, a lot of methods have been proposed to ameliorate the quality of the perovskite thin film, for example, additive engineering, ,, buried engineering, , precursor solvent, and component engineering. , Besides, the antisolvent engineering , has been considered one of the most effective ways to enhance the quality of the perovskite film. In addition to finding more suitable and greener antisolvents or mixing antisolvents engineers, , introducing additives into antisolvents is also an important content of antisolvent engineering.…”

“…The quality of the perovskite film plays a key role in preparing the PSCs with high PCE. 7,10,11 As yet, a lot of methods have been proposed to ameliorate the quality of the perovskite thin film, for example, additive engineering, 5,12,13 buried engineering, 14,15 precursor solvent, and component engineering. 16,17 Besides, the antisolvent engineering 18,19 has been considered one of the most effective ways to enhance the quality of the perovskite film.…”