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An eco‐friendly water‐soluble fluorene‐based polyelectrolyte as interfacial layer for efficient inverted polymer solar cells
Author(s) -
Li Jianfeng,
Lv Jie,
Peng Yichun,
Cao Xiaodong,
Tong Junfeng,
Xia Yangjun
Publication year - 2018
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.4334
Subject(s) - materials science , cathode , polymer solar cell , fluorene , active layer , energy conversion efficiency , optoelectronics , polymer , work function , layer (electronics) , chemical engineering , analytical chemistry (journal) , nanotechnology , organic chemistry , thin film transistor , composite material , chemistry , engineering
A conjugated polyelectrolyte poly(9,9‐bis(3′‐[( N , N ‐dimethyl)‐ N ‐ethylammonium]‐propyl)‐2,7‐fluorene dibromide) (PFBr) with the feature of environmental friendliness and cheapness was successfully used in polymer solar cells (PSCs) as the cathode interfacial layer (CIL). And we successfully demonstrate that the PFBr can build interfacial dipoles at the CIL/cathode interfaces, leading to reduce cathode work functions and improve open‐circuit voltages, which decrease interfacial energy loss at the cathode. It not only improves the electron transfer efficiency but also inhibits the charge carrier recombination at the contact interface. Impedance spectra revealed that the optimal device with the smallest charge transport time constant of 2.83 microseconds was achieved under the concentration of 2 mg mL −1 of PFBr, which suggests efficient electron transport on the interface between the organic active layer and the indium tin oxide cathode. Moreover, as a consequence, the power conversion efficiency of the PSCs increases to 3.83% (with PFBr as CIL) from 1.89% (without any CIL), based on the poly(3‐hexylthiophene) and [6,6]‐phenyl C 61 ‐butyric acid methyl ester bulk heterojunction active layer. Therefore, our observation can demonstrate PFBr is a prospective candidate as CIL for constructing low‐cost, large‐area, and flexible PSCs.