Direct bandgap perovskite and indirect bandgap Si, which form the two active layers in a tandem solar cell configuration, have different optoelectronic properties and thicknesses. The charge-carrier dynamics of the two-terminal perovskite-on-Si tandem solar cell in response to a supercontinuum light pulse is studied using transient photocurrent (TPC) measurements. Spectral dependence of TPC lifetime is observed and can be classified into two distinct timescales based on their respective carrier generation regions. The faster timescale (∼500 ns) corresponding to the spectral window (300–750 nm) represents the top-perovskite sub-cell, while the slower timescale regime of ∼25 μs corresponds to the bottom-Si sub-cell (>700 nm). Additionally, under light-bias conditions, the transient carrier dynamics of the perovskite sub-cell is observed to be coupled with that of the Si sub-cell. A sharp crossover from the fast-response to a slow-response of the device as a function of the light-bias intensity is observed. These results along with a model based on transfer matrix formulation highlight the role of charge-carrier dynamics in accessing higher efficiencies in tandem solar cells. The carrier transit times and lifetimes in addition to their optical properties need to be taken into account for optimizing the performance.

中文翻译：

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使用瞬态光电流光谱洞察钙钛矿/硅串联太阳能电池中的电荷载流子动力学

直接带隙钙钛矿和间接带隙硅构成串联太阳能电池结构中的两个活性层，它们具有不同的光电特性和厚度。使用瞬态光电流 (TPC) 测量研究了两端钙钛矿硅串联太阳能电池响应超连续谱光脉冲的载流子动力学。观察到 TPC 寿命的光谱依赖性，并且可以根据它们各自的载流子生成区域将其分为两个不同的时间尺度。对应于光谱窗口 (300–750 nm) 的较快时间尺度 (~500 ns) 代表顶部钙钛矿子电池，而 ~25 μs 的较慢时间尺度对应于底部 Si 子电池 (>700 nm) ). 此外，在光偏置条件下，观察到钙钛矿子电池的瞬态载流子动力学与 Si 子电池的瞬态载流子动力学耦合。观察到作为光偏置强度函数的器件从快速响应到慢速响应的急剧交叉。这些结果以及基于转移矩阵公式的模型突出了电荷载流子动力学在串联太阳能电池中获得更高效率的作用。为了优化性能，除了光学特性外，还需要考虑载流子传输时间和寿命。这些结果以及基于转移矩阵公式的模型突出了电荷载流子动力学在串联太阳能电池中获得更高效率的作用。为了优化性能，除了光学特性外，还需要考虑载流子传输时间和寿命。这些结果以及基于转移矩阵公式的模型突出了电荷载流子动力学在串联太阳能电池中获得更高效率的作用。为了优化性能，除了光学特性外，还需要考虑载流子传输时间和寿命。