Intrinsic measurements of exciton transport in photovoltaic cells
Intrinsic measurements of exciton transport in photovoltaic cells
复制标题
DOI：
10.1038/s41467-019-09062-8
复制
发表时间：
2019-01
影响因子：
16.6
通讯作者：
Zhang Tao;Dana B. Dement;V. Ferry;R. Holmes
中科院分区：
文献类型：
--
作者：
Zhang Tao;Dana B. Dement;V. Ferry;R. Holmes
有机光伏电池对激子捕获特别敏感，因此是表征激子扩散的有用平台。虽然器件光电流光谱可以用于提取激子扩散长度，但这种方法经常受到未知界面复合损失的限制。我们解决了这个限制，并展示了一个通用的，基于设备的光电流比测量提取的本征扩散长度。由于界面损耗不是有源层特定的，所以供体材料和受体材料的内部量子效率的比率抵消了这个量。我们进一步表明，这种测量允许提取有关激子弛豫和电荷分离过程的额外的设备相关的信息。通过测量发光和暗材料以及小分子和聚合物活性材料和半导体量子点的激子输运，证明了这种方法的一般性。因此，我们展示了一种广泛适用的基于器件的方法来探测本征活性材料激子扩散长度。
Organic photovoltaic cells are partiuclarly sensitive to exciton harvesting and are thus, a useful platform for the characterization of exciton diffusion. While device photocurrent spectroscopy can be used to extract the exciton diffusion length, this method is frequently limited by unknown interfacial recombination losses. We resolve this limitation and demonstrate a general, device-based photocurrent-ratio measurement to extract the intrinsic diffusion length. Since interfacial losses are not active layer specific, a ratio of the donor- and acceptor-material internal quantum efficiencies cancels this quantity. We further show that this measurement permits extraction of additional device-relevant information regarding exciton relaxation and charge separation processes. The generality of this method is demonstrated by measuring exciton transport for both luminescent and dark materials, as well as for small molecule and polymer active materials and semiconductor quantum dots. Thus, we demonstrate a broadly applicable device-based methodology to probe the intrinsic active material exciton diffusion length.