Premium
Lithium‐Ion‐Based Conjugated Polyelectrolyte as an Interface Material for Efficient and Stable Non‐Fullerene Organic Solar Cells
Author(s) -
Li Junli,
Liu Jikang,
Liu Xiangfu,
Wang Rongwen,
Zhang Jian,
Tu Guoli
Publication year - 2019
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201802939
Subject(s) - materials science , lithium (medication) , organic solar cell , chemical engineering , conjugated system , polyfluorene , indium tin oxide , polyelectrolyte , x ray photoelectron spectroscopy , layer (electronics) , nanotechnology , polymer , composite material , medicine , engineering , endocrinology
An eco‐friendly n‐type water/alcohol‐soluble conjugated polyelectrolyte PF EO SO 3 Li was synthesized and applied as a cathode interfacial layer in organic solar cells. The π‐delocalized polyfluorene backbone has an intimate connection with the hydrophobic active layer, and the side chain with lithium ion may move toward the ZnO layer through the self‐assembly property of conjugated polyelectrolytes. UV photoelectron spectroscopy indicated that modification with PF EO SO 3 Li dramatically lowers the work function of indium‐doped tin oxide (ITO)/ZnO and may form strong interfacial dipoles between ZnO and the active layer. Meanwhile, introduction of lithium ions as spectator cations may contribute to reduction of the intrinsic surface defects of ZnO. The green emission in the photoluminescence spectrum of ZnO disappeared after modification with PF EO SO 3 Li. In addition, the roughness of ZnO barely changed after coating with PF EO SO 3 Li, and the surface became more hydrophobic, which demonstrates that the thin conjugated polyelectrolyte layer exhibits good adhesion with both ZnO and the active layer. These phenomena indicate that the introduction of PF EO SO 3 Li makes ITO/ZnO an efficient cathode. As a result, inverted organic solar cell devices with ZnO/PF EO SO 3 Li double‐interlayers exhibit high efficiencies of 11.7 and 10.6 % for PBDB‐T:IT‐M and PBDB‐T:ITIC blend systems, respectively.