发表机构
Swansea University; Åbo Akademi University（斯旺西大学; 奥布阿尔托大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究指出有机太阳能电池光电流-有效电压曲线无法反映激子解离概率与自由电荷生成效率，经漂移-扩散模型及实验验证，该表观概率实际对应短路电荷收集效率，建议勿在高效非富勒烯体系中使用该方法。
AI 中文摘要
有机太阳能电池的光电流通常被绘制成与有效电压的关系曲线，用于提取激子解离概率，并通过该概率得到自由电荷生成效率，但实际上光电流无法反映这两个参数。本研究采用一种漂移-扩散模型，其中自由电荷生成与电场无关，损失仅源于双分子复合，结果表明，即使激子完全解离，该方法得到的表观解离概率也远低于1。在载流子迁移率和复合强度的广泛变化范围内，表观解离概率是填充因子的单值函数，且与短路电荷收集效率一致，既不反映生成产率，也不超出填充因子已显示的收集相关信息。即使在理想传输条件下，归一化光电流也会在低于1的数值处达到饱和，该饱和值是由光生载流子与注入平衡电荷的复合所设定的、与强度无关的一阶极限。将该方法应用于4个独立已知生成效率的有机太阳能电池，结果显示表观解离概率追踪的是短路收集效率而非生成产率。因此，本研究建议不要使用该构建方法，尤其是在当前处于技术前沿的高效非富勒烯受体体系中。
英文摘要
The photocurrent of an organic solar cell is routinely plotted against an effective voltage and used to extract an exciton dissociation probability, and through it a free-charge generation efficiency. The photocurrent measures neither. Using a drift-diffusion model in which free-charge generation is field independent and losses occur only by bimolecular recombination, we show that the apparent dissociation probability returned by this procedure lies well below unity even for complete dissociation. Across wide variations of carrier mobility and recombination strength it is a single-valued function of the fill factor and coincides with the short-circuit charge collection efficiency, reporting neither the generation yield nor anything about collection beyond what the fill factor already shows. Even for ideal transport the normalised photocurrent saturates below unity at an intensity-independent first-order limit set by recombination of photogenerated carriers with injected equilibrium charge. Applied to four organic solar cells whose generation efficiencies are known independently, the apparent dissociation probabilities track the short-circuit collection efficiency rather than the generation yield. We therefore suggest this construction not be used, particularly in the high-efficiency non-fullerene acceptor systems that are now state of the art.
