title: High-Performance Polymer Solar Cells Based on a Wide-Bandgap Polymer Containing Pyrrolo[3,4-f]benzotriazole-5,7-dione with a Power Conversion Efficiency of 8.63.
abstract: A novel donor-acceptor type conjugated polymer based on a building block of 4,8-di(thien-2-yl)-6-octyl-2-octyl-5H-pyrrolo[3,4-f]benzotriazole-5,7(6H)-dione (TZBI) as the acceptor unit and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo-[1,2-b:4,5-b']dithiophene as the donor unit, named as PTZBIBDT, is developed and used as an electron-donating material in bulk-heterojunction polymer solar cells. The resulting copolymer exhibits a wide bandgap of 1.81 eV along with relatively deep highest occupied molecular orbital energy level of -5.34 eV. Based on the optimized processing conditions, including thermal annealing, and the use of a water/alcohol cathode interlayer, the single-junction polymer solar cell based on PTZBIBDT:PC71BM ([6,6]-phenyl-C71-butyric acid methyl ester) blend film affords a power conversion efficiency of 8.63% with an open-circuit voltage of 0.87 V, a short circuit current of 13.50 mA cm-2, and a fill factor of 73.95%, which is among the highest values reported for wide-bandgap polymers-based single-junction organic solar cells. The morphology studies on the PTZBIBDT:PC71BM blend film indicate that a fibrillar network can be formed and the extent of phase separation can be mani-pulated by thermal annealing. These results indicate that the TZBI unit is a very promising building block for the synthesis of wide-bandgap polymers for high-performance single-junction and tandem (or multijunction) organic solar cells.
authors.affiliation: Institute of Polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 P.R. China.
authors.forename: Liuyuan
authors.initials: L
authors.lastname: Lan
authors.affiliation: Institute of Polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 P.R. China.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Chen
authors.affiliation: State Key Laboratory for Artificial Microstructure and Mesoscopic Physics School of Physics Peking University Beijing 100871 P.R. China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Hu
authors.affiliation: Institute of Polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 P.R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Ying
authors.affiliation: State Key Laboratory for Artificial Microstructure and Mesoscopic Physics School of Physics Peking University Beijing 100871 P.R. China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhu
authors.affiliation: Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley CA 94720 USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: Materials Sciences Division Lawrence Berkeley National Laboratory Berkeley CA 94720 USA.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Russell
authors.affiliation: Institute of Polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 P.R. China.
authors.forename: Fei
authors.initials: F
authors.lastname: Huang
authors.affiliation: Institute of Polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 P.R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao
keywords: polymer solar cells; pyrrolo[3,4‐f]benzotriazole‐5,7‐dione; wide‐bandgap polymer