TY - JOUR
T1 - Surface-segregated monolayers
T2 - A new type of ordered monolayer for surface modification of organic semiconductors
AU - Wei, Qingshuo
AU - Tajima, Keisuke
AU - Tong, Yujin
AU - Ye, Shen
AU - Hashimoto, Kazuhito
PY - 2009/12/9
Y1 - 2009/12/9
N2 - We report a new type of ordered monolayer for the surface modification of organic semiconductors. Fullerene derivatives with fluorocarbon chains ([6,6]-phenyl-C61-buryric acid 1H,1H-perfluoro-1-alkyl ester or FCn) spontaneously segregated as a monolayer on the surface of a [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) film during a spin-coating process from the mixture solutions, as confirmed by X-ray photoelectron spectroscopy (XPS). Ultraviolet photoelectron spectroscopy (UPS) showed the shift of ionization potentials (IPs) depending on the fluorocarbon chain length, indicating the formation of surface dipole moments. Surface-sensitive vibrational spectroscopy, sum frequency generation (SFG) revealed the ordered molecular orientations of the C60 moiety in the surface FCn layers. The intensity of the SFG signals from FC n on the surface showed a clear odd-even effect when the length of the fluorocarbon chain was changed. This new concept of the surface-segregated monolayer provides a facile and versatile approach to modifying the surface of organic semiconductors and is applicable to various organic optoelectronic devices.
AB - We report a new type of ordered monolayer for the surface modification of organic semiconductors. Fullerene derivatives with fluorocarbon chains ([6,6]-phenyl-C61-buryric acid 1H,1H-perfluoro-1-alkyl ester or FCn) spontaneously segregated as a monolayer on the surface of a [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) film during a spin-coating process from the mixture solutions, as confirmed by X-ray photoelectron spectroscopy (XPS). Ultraviolet photoelectron spectroscopy (UPS) showed the shift of ionization potentials (IPs) depending on the fluorocarbon chain length, indicating the formation of surface dipole moments. Surface-sensitive vibrational spectroscopy, sum frequency generation (SFG) revealed the ordered molecular orientations of the C60 moiety in the surface FCn layers. The intensity of the SFG signals from FC n on the surface showed a clear odd-even effect when the length of the fluorocarbon chain was changed. This new concept of the surface-segregated monolayer provides a facile and versatile approach to modifying the surface of organic semiconductors and is applicable to various organic optoelectronic devices.
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U2 - 10.1021/ja9057053
DO - 10.1021/ja9057053
M3 - Article
C2 - 19911787
AN - SCOPUS:72249102153
VL - 131
SP - 17597
EP - 17604
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 48
ER -