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Poly( N ‐vinylpyrrolidone)‐Decorated Reduced Graphene Oxide with ZnO Grown In Situ as a Cathode Buffer Layer for Polymer Solar Cells
Author(s) -
Hu Ting,
Chen Lie,
Yuan Kai,
Chen Yiwang
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201404025
Subject(s) - graphene , materials science , cathode , chemical engineering , oxide , nanoclusters , nanoparticle , nanocomposite , layer (electronics) , polymer solar cell , nanotechnology , polymer , composite material , chemistry , engineering , metallurgy
A ZnO@reduced graphene oxide–poly( N ‐vinylpyrrolidone) (ZnO@RGO‐PVP) nanocomposite, prepared by in situ growth of ZnO nanoparticles on PVP‐decorated RGO (RGO‐PVP) was developed as a cathode buffer layer for improving the performance of polymer solar cells (PSCs). PVP not only favors homogeneous distribution of the RGO through the strong π–π interactions between graphene and PVP molecules, but also acts as a stabilizer and bridge to control the in situ growth of sol–gel‐derived ZnO nanoparticles on the surface of the graphene. At the same time, RGO provides a conductive connection for independent dispersion of ZnO nanoparticles to form uniform nanoclusters with fewer domain boundaries and surface traps. Moreover, the LUMO level of ZnO is effectively improved by modification with RGO‐PVP. Compared to bare ZnO, a ZnO@RGO‐PVP cathode buffer layer substantially reduces the recombination of carriers, increases the electrical conductivity, and enhances electron extraction. Consequently, the power conversion efficiency of an inverted device based on thieno[3,4‐ b ]thiophene/benzodithiophene (PTB7):[6,6]‐phenyl C 71 ‐butyric acid methyl ester (PC 71 BM) with ZnO@RGO‐PVP as cathode buffer layer was greatly improved to 7.5 % with improved long‐term stability. The results reveal that ZnO@RGO‐PVP is universally applicable as a cathode buffer layer for improving the performance of PSCs.