Transient photovoltage (TPV) measurements are frequently used to study recombination processes in thin‐film solar cells by probing the decay of a small optically induced voltage perturbation to infer the charge carrier dynamics of devices at open circuit. However, the validity of this method to probe organic semiconductors has recently come into doubt due to large discrepancies in the reported carrier lifetime values for the same systems and the reporting of unrealistic reaction order values. Herein, the validity of TPV to extract reliable charge carrier lifetimes in thin‐film solar cells is explored through the use of time‐dependent drift‐diffusion simulations and measurements. It is found that in low‐mobility materials, TPV serves primarily as a probe of charge carrier redistribution in the bulk rather than bulk recombination dynamics and that the extracted time constant is highly mobility dependent. To address this shortcoming, transient photocharge, a new technique to measure the charge carrier density during photovoltage decay, is introduced and applied to study the recombination dynamics in a series of (fullerene and nonfullerene) organic solar cell systems. It is shown that using this technique the charge carrier recombination lifetime in the active layer is more accurately determined.

中文翻译：

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克服用于研究有机太阳能电池复合的瞬态光电压测量的局限性

瞬态光电压（TPV）测量通常用于研究薄膜太阳能电池中的重组过程，方法是探测较小的光感应电压扰动的衰减，以推断开路设备的电荷载流子动态。然而，由于相同系统的报告的载流子寿命值和不真实的反应阶次值的报告中的巨大差异，该方法探测有机半导体的有效性最近已受到质疑。在本文中，通过使用时间相关的漂移扩散模拟和测量方法，探索了TPV提取薄膜太阳能电池中可靠的载流子寿命的有效性。发现在低流动性材料中，TPV主要用作整体中电荷载子重新分布的探针，而不是整体重组动力学，并且提取的时间常数高度依赖于迁移率。为了解决这一缺点，引入了一种瞬态光电荷技术，该技术是一种在光电压衰减期间测量电荷载流子密度的新技术，并用于研究一系列（富勒烯和非富勒烯）有机太阳能电池系统中的复合动力学。结果表明，使用该技术可以更准确地确定活性层中的电荷载流子复合寿命。介绍并应用于研究一系列（富勒烯和非富勒烯）有机太阳能电池系统中的复合动力学。结果表明，使用该技术可以更准确地确定活性层中的电荷载流子复合寿命。介绍并应用于研究一系列（富勒烯和非富勒烯）有机太阳能电池系统中的复合动力学。结果表明，使用该技术可以更准确地确定活性层中的电荷载流子复合寿命。