N-type doping in electron transport materials is an effective way to improve the electron collection and enhance the performance of the perovskite solar cells (PSCs). Here, for the first time, an antibiotic and antimicrobial compound of 1-(o-Tolyl) biguanide (oTb) is used to dope the electron transport material of phenyl-C61-butyric acid methyl ester (PCBM). The oTb doping into the PCBM can increase the conductivity and reduce the work function of the PCBM. The oTb doping can significantly enhance the fill factor (FF) of the perovskite solar cells with the structure of glass/ITO/NiOx/MAPbI3/(oTb)PCBM/(PEIE)/Ag. For the cells without PEIE (polyethylenimine ethoxylated) coating, the oTb doping increases the FF from 0.57 to 0.73. S-shaped of the current density-voltage (J-V) characteristic under illumination is removed after the oTb doping. For the cells with PEIE coating between the (oTb)PCBM and Ag, the oTb doping increases the FF from 0.70 to 0.82. These results show the potential of the oTb as an n-dopant in the applications of perovskite solar cells.
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The work was supported by the National Natural Science Foundation of China (Grant Nos. 21474035 and 51773072), the Recruitment Program of Global Youth Experts, the Huazhong University of Science and Technology (HUST) Innovation Research Fund (Nos. 2016JCTD111 and 2017KFKJXX012), the Science and Technology Program of Hubei Province (No. 2017AHB040) and China Postdoctoral Science Foundation funded project (No. 2016M602289).
Ru Ge received her B.S. degree from Huazhong University of Science and Technology (HUST) in 2016. She is now a M.S. student in Wuhan National Laboratory for Optoelectronics, HUST, Wuhan. Her current research interests focus on conducting polymers and interface engineering in organic photovoltaics.
Fei Qin received his B.S. degree from Huazhong University of Science and Technology (HUST) in 2015. He is now a Ph.D. candidate in Wuhan National Laboratory for Optoelectronics, HUST,Wuhan. His Ph. D. research includes interface engineering and flexible, stretchable solar cells.
Lin Hu received his B.S. (2013) and M.S. (2016) degrees at Nanchang University, China. He is currently pursuing his Ph.D. under the supervision of Prof. Yinhua Zhou in Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan. His current research interests focus on materials development and device engineering in organic and perovskite solar cells.
Sixing Xiong received his B.S. degree from Huazhong University of Science and Technology in 2014. He is now a Ph.D. candidate in Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan. His research includes device engineering in flexible solar cells and printed electronics.
Prof. Yinhua Zhou received his bachelor (2003) and Ph.D. (2008) degrees both from Jilin University, China. During his Ph.D. study, he spent one year in Prof. Olle Inganäs group as a visiting Ph.D. student in 2007–2008. After that, he worked as postdoctoral fellow in the Georgia Institute of Technology from 2009 to 2013 with Prof. Bernard Kippelen. Since October of 2013, he started the current position as a faculty member in Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology. His research interest includes conducting polymers, organic photovoltaics and printed electronics.
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Ge, R., Qin, F., Hu, L. et al. High fill factor over 82% enabled by a biguanide doping electron transporting layer in planar perovskite solar cells. Front. Optoelectron. 11, 360–366 (2018). https://doi.org/10.1007/s12200-018-0847-4