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Abstract Faux‐hawk fullerenes are promising candidates for high‐performance organic field‐effect transistors (OFETs). They show dense molecular packing and high thermal stability. Furthermore, in contrast to most other C60derivates, functionalization of the fullerene core by the fluorinated group C6F4CF2does not increase their lowest unoccupied orbital position, which allows the use of air‐stable molecular n‐dopants to optimize their performance. The influence of n‐doping on the performance of OFETs based on the faux‐hawk fullerene 1,9‐C60(cyclo‐CF2(2‐C6F4)) (C60FHF) is studied. An analytic model for n‐doped transistors is presented and used to clarify the origin of the increase in the subthreshold swing usually observed in doped OFETs. It is shown that the increase in subthreshold swing can be minimized by using a bulk dopant layer at the gate dielectric/C60FHF layer instead of a mixed host:dopant layer. Following an optimization of the OFETs, an average electron mobility of 0.34 cm2 V−1 s−1, a subthreshold swing below 400 mV dec−1for doped transistors, and a contact resistance of 10 kΩ cm is obtained, which is among the best performance for fullerene based n‐type semiconductors.
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Probing the presence and absence of metal-fullerene electron transfer reactions in helium nanodroplets by deflection measurements
Metal-fullerene compounds are characterized by significant electron transfer to the fullerene cage, giving rise to an electric dipole moment. We use the method of electrostatic beam deflection to verify whether such reactions take place within superfluid helium nanodroplets between an embedded C 60 molecule and either alkali (heliophobic) or rare-earth (heliophilic) atoms. The two cases lead to distinctly different outcomes: C 60 Na n ( n = 1–4) display no discernable dipole moment, while C 60 Yb is strongly polar. This suggests that the fullerene and small alkali clusters fail to form a charge-transfer bond in the helium matrix despite their strong van der Waals attraction. The C 60 Yb dipole moment, on the other hand, is in agreement with the value expected for an ionic complex.
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- PAR ID:
- 10329401
- Date Published:
- Journal Name:
- Physical Chemistry Chemical Physics
- Volume:
- 24
- Issue:
- 17
- ISSN:
- 1463-9076
- Page Range / eLocation ID:
- 10378 to 10383
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D2CP00751G
