The effects of additives SnF₂ (10%) and EDAI₂ (1%) on the dynamics of carrier relaxation of formamidinium tin triiodide (FASnI₃) perovskite were studied using femtosecond transient absorption spectra (TAS) with excitation at 600 and 870 nm. The TAS were analyzed according to a parallel sequential kinetic model with a global fit through singular-value decomposition. For excitation at 600 nm, two relaxation paths were found: one involved hot and cold carriers in the bulk state undergoing shallow bulk-defect-mediated charge recombination; the other involved trap carriers in the surface state undergoing deep surface-defect-mediated charge recombination. For excitation at 870 nm, only cold carriers were subjected to the bulk-state relaxation channel. Our spectral results indicate significant effects of the additives on retarding charge recombination in both bulk and surface states as well as decreasing the bandgap renormalization energy, the bandwidth of the photobleaching (PB) band, and the Stokes shift between the PB and photoluminescence bands, explaining how the device performance of FASnI₃ solar cells became enhanced in the presence of SnF₂ and EDAI₂.

中文翻译：

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在添加剂存在和存在下，钙钛矿型飞秒瞬态吸收光谱和载体弛豫动力学。

添加剂SnF ₂（10％）和EDAI ₂（1％）对三碘甲form锡（FASnI ₃）载流子弛豫动力学的影响使用飞秒瞬态吸收光谱（TAS）在600和870 nm激发下研究了钙钛矿。通过具有奇异值分解的全局拟合的并行顺序动力学模型对TAS进行了分析。对于在600 nm处的激发，发现了两条弛豫路径：一条涉及散装状态下的热载流子和冷载流子，经历了浅的散装缺陷介导的电荷重组。另一类涉及处于表面状态的陷阱载流子，它们经历了深层的表面缺陷介导的电荷复合。为了在870 nm处激发，只有冷的载流子才经历了整体弛豫通道。我们的光谱结果表明，这些添加剂在延缓体态和表面态中电荷的重组以及降低带隙重整化能方面均具有显着效果，在SnF ₂和EDAI ₂的存在下_3个太阳能电池变得增强。