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A Novel, Weakly N‐Doped Cathode‐Modifying Layer in Organic Solar Cells
Author(s) -
Chen Chunxin,
Xue Peiyao,
Lu Heng,
Wang Jiayu,
Jia Boyu,
Li Yawen,
Qin Dashan,
Lin Yuze,
Zhan Xiaowei
Publication year - 2021
Publication title -
energy technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.91
H-Index - 44
eISSN - 2194-4296
pISSN - 2194-4288
DOI - 10.1002/ente.202100281
Subject(s) - materials science , doping , diimide , organic solar cell , dopant , optoelectronics , cathode , active layer , polymer solar cell , electron mobility , perylene , energy conversion efficiency , layer (electronics) , nanotechnology , chemistry , polymer , organic chemistry , molecule , composite material , thin film transistor
A novel blend thin film ( N,N ‐dimethyl‐ammonium N ‐oxide)propyl perylene diimide mixed with polyethylenimine ethoxylated (PDINO:PEIE) is provided as a cathode‐modifying layer (CML) in organic solar cells (OSCs). Compared with PDINO, PDINO:PEIE shows increased electron conduction, due to the weak n‐doping of PDINO by the amino groups of PEIE, improving the balance of hole/electron mobility and thereby the fill factor of the device. Moreover, the addition of PEIE in PDINO enables a smoother morphology of the device and helps block the cathode diffusion into the photoactive layer, reducing trap‐assisted recombination in the exciton formation zone and thereby, increasing the open‐circuit voltage of the device. As a result, PDINO:PEIE enables greater power conversion efficiency (PCE) of fullerene OSCs than PDINO. It is also shown that, relative to conventional CMLs, PDINO:PEIE presents higher PCEs and comparable stabilities of nonfullerene OSCs. The blend thin films containing the small‐molecular host and weak polymeric n‐dopant are promising CMLs to integrate high electron mobility, good film‐forming property, low recombination loss, no migration of counter ions, and good stabilities.