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The Effect of Electrostatic Interaction on n‐Type Doping Efficiency of Fullerene Derivatives
Author(s) -
Liu Jian,
Maity Sudeshna,
Roosloot Nathan,
Qiu Xinkai,
Qiu Li,
Chiechi Ryan C.,
Hummelen Jan C.,
Hauff Elizabeth,
Koster L. Jan Anton
Publication year - 2019
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.201800959
Subject(s) - doping , materials science , triethylene glycol , fullerene , raman spectroscopy , organic semiconductor , organic solar cell , dopant , dissociation (chemistry) , chemical physics , chemical engineering , nanotechnology , organic chemistry , optoelectronics , polymer chemistry , polymer , chemistry , optics , physics , composite material , engineering
Abstract The molecular doping of organic semiconductors represents a key strategy for advancing organic electronic applications. However, the n‐doping of organic materials is usually less efficient than p‐doping and strategies toward the design of more efficient n‐doping still remain less explored. In this contribution, the impact of electrostatic interaction is explored on the doping efficiency of fullerene derivatives. [6,6]‐Phenyl‐C 61 ‐butyric acid methyl ester (PCBM) and a [60]fulleropyrrolidine with a more polarizable triethylene glycol type side chain (PTEG‐1) are employed for a comparative study. It is found that the doping efficiency of lightly doped PCBM layers is limited to a few percent, while doped PTEG‐1 films exhibit very high doping efficiency approaching 100%. The enhanced n‐doping of PTEG‐1 compared with that of PCBM is further substantiated by Raman and Fourier transform infrared spectroscopic studies. The activation energy for charge generation in doped PTEG‐1 is much smaller than that of doped PCBM, which confirms a higher probability for dissociation of charge transfer complexes in the former compared to the latter. The enhanced molecular n‐doping for PTEG‐1 is attributed to the electrostatic interaction between the charge transfer complex and the polar environment offered by the triethylene glycol diether side chain.