We combine steady-state with transient optoelectronic characterization methods to understand the operation of photovoltaic devices based on a benchmark model squaraine blended with a fullerene acceptor. These devices suffer from a gradual decrease in the fill factor when increasing the active layer thickness and incident light intensity. Using transient photocurrent, transient photovoltage, and bias-assisted charge extraction measurements, we show that the fill factor deteriorates due to slow charge carrier collection competing with bimolecular recombination. Under normal operating conditions, we find a bimolecular recombination rate constant of ∼10–17 m3 s−1, which corresponds to a reduction of one to two orders of magnitude compared to the Langevin model.

中文翻译：

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揭示方酸基体异质结太阳能电池的复合动力学

我们将稳态与瞬态光电表征方法相结合，以了解基于与富勒烯受体混合的基准模型方酸碱的光伏器件的运行。当增加有源层厚度和入射光强度时，这些器件的填充因子会逐渐降低。使用瞬态光电流、瞬态光电压和偏置辅助电荷提取测量，我们表明填充因子由于缓慢的电荷载流子收集与双分子重组竞争而恶化。在正常操作条件下，我们发现双分子复合速率常数约为 10-17 m3 s-1，与 Langevin 模型相比，这对应于减少一到两个数量级。