Bartesaghi Davide, Pérez Irene Del Carmen, Kniepert Juliane, Roland Steffen, Turbiez Mathieu, Neher Dieter, Koster L Jan Anton
1] Department of Photophysics and Optoelectronics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, NL-9747AG Groningen, The Netherlands [2] Dutch Polymer Institute, P. O. Box 902, 5600AX Eindhoven, The Netherlands.
Department of Photophysics and Optoelectronics, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, NL-9747AG Groningen, The Netherlands.
Nat Commun. 2015 May 7;6:7083. doi: 10.1038/ncomms8083.
Among the parameters that characterize a solar cell and define its power-conversion efficiency, the fill factor is the least well understood, making targeted improvements difficult. Here we quantify the competition between charge extraction and recombination by using a single parameter θ, and we demonstrate that this parameter is directly related to the fill factor of many different bulk-heterojunction solar cells. Our finding is supported by experimental measurements on 15 different donor:acceptor combinations, as well as by drift-diffusion simulations of organic solar cells in which charge-carrier mobilities, recombination rate, light intensity, energy levels and active-layer thickness are all varied over wide ranges to reproduce typical experimental conditions. The results unify the fill factors of several very different donor:acceptor combinations and give insight into why fill factors change so much with thickness, light intensity and materials properties. To achieve fill factors larger than 0.8 requires further improvements in charge transport while reducing recombination.
在表征太阳能电池并定义其功率转换效率的参数中，填充因子是理解最少的，这使得有针对性的改进变得困难。在这里，我们通过使用单个参数θ来量化电荷提取和复合之间的竞争，并且我们证明该参数与许多不同体异质结太阳能电池的填充因子直接相关。我们的发现得到了对15种不同供体：受体组合的实验测量以及有机太阳能电池的漂移扩散模拟的支持，在该模拟中，电荷载流子迁移率、复合率、光强度、能级和活性层厚度都在很宽的范围内变化，以再现典型的实验条件。这些结果统一了几种非常不同的供体：受体组合的填充因子，并深入了解了为什么填充因子会随厚度、光强度和材料特性变化如此之大。要实现大于0.8的填充因子，需要在减少复合的同时进一步改善电荷传输。
