@article{Bauer2019, 
author = {Nicole Bauer and Qianqian Zhang and Jeromy James Rech and Shuixing Dai and Zhengxing Peng and Harald Ade and Jiayu Wang and Xiaowei Zhan and Wei You},
title = {The impact of fluorination on both donor polymer and non-fullerene acceptor: The more fluorine, the merrier},
year = {2019},
journal = {Nano Research},
volume = {12},
number = {9},
pages = {2400-2405},
keywords = {fluorination, organic solar cells, non-fullerene acceptors, bulk heterojunction},
url = {https://www.sciopen.com/article/10.1007/s12274-019-2362-3},
doi = {10.1007/s12274-019-2362-3},
abstract = {Fluorination of the donor polymer or non-fullerene acceptor (NFA) in an organic photovoltaic device is an effective method to improve device efficiency. Although there have been many studies on donor polymer fluorination, blends containing both a fluorinated donor and fluorinated NFA have rarely been reported. In this study, we use two donor polymers (4′-FT-HTAZ and 4′-FT-FTAZ) and two NFAs (ITIC-Th and ITIC-Th1) with different amounts of fluorine (from 2F to 6F) to investigate how the degree of fluorination in a blend impacts device performance. We find that fluorinating the NFA leads to a higher short-circuit current density (Jsc) and fill factor (FF), however, the open-circuit voltage (Voc) is decreased due to a depressed lowest unoccupied molecular orbital (LUMO) level. Adding additional fluorine to the donor polymer does not have a large effect on the Jsc or FF, but it does lead to an improved Voc. By fluorinating the NFA and having more fluorine on the donor polymer, we obtain both a high Jsc and Voc simultaneously, leading to a power conversion efficiency over 10% in the case of 4′-FT-FTAZ: ITIC-Th1, which has the most amount of fluorine (6F).}
}