Fine-tuning of the chemical structure of photoactive materials for highly efficient organic photovoltaics
Fine-tuning of the chemical structure of photoactive materials for highly efficient organic photovoltaics
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微调光活性材料的化学结构以实现高效有机光伏
DOI：
10.1038/s41560-018-0263-4
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发表时间：
2018-12-01
期刊：
影响因子：
56.7
通讯作者：
Cao, Yong
中科院分区：
文献类型：
--
作者：
Fan, Baobing;Du, Xiaoyan;Cao, Yong
有机光伏的性能在很大程度上取决于短路电流密度（J(sc)）和开路电压（V-oc）的平衡。例如，活性材料光学带隙的减少会增加 J(sc)，不可避免地会导致 V-oc 随之减少。在这里，我们证明仔细调整光活性材料的化学结构可以同时增强 J(sc) 和 V-oc。基于良好匹配的材料组合的非富勒烯有机光伏器件在 1 cm(2) 的器件面积上表现出经认证的 12.25% 的高功率转换效率。通过结合傅里叶变换光电流光谱和电致发光，我们证明了低但不可忽略的电荷转移态的存在作为 V-oc 损失的可能根源。这项研究强调，通过减小带隙来提高效率需要仔细的材料设计，以最大限度地减少非辐射 V-oc 损失。
The performance of organic photovoltaics is largely dependent on the balance of short-circuit current density (J(sc)) and opencircuit voltage (V-oc). For instance, the reduction of the active materials' optical bandgap, which increases the J(sc), would inevitably lead to a concomitant reduction in V-oc. Here, we demonstrate that careful tuning of the chemical structure of photoactive materials can enhance both J(sc), and V-oc simultaneously. Non-fullerene organic photovoltaics based on a well-matched materials combination exhibit a certified high power conversion efficiency of 12.25% on a device area of 1 cm(2). By combining Fouriertransform photocurrent spectroscopy and electroluminescence, we show the existence of a low but non-negligible charge transfer state as the possible origin of V-oc loss. This study highlights that the reduction of the bandgap to improve the efficiency requires a careful materials design to minimize non-radiative V-oc losses.