Solution processible organic transistors and circuits based on a C70 methanofullerene

Abstract

We demonstrate ambipolar charge transport in organic field-effect transistors based on the solution processible methanofullerene ͓6,6͔-phenyl-C 71 -butyric acid methyl ester ͓͑70͔PCBM͒. The electron mobility measured in the linear and saturated regimes is approximately equal and of the order of 1 ϫ 10 −3 cm 2 / V s. In the linear regime, mobility is thermally activated with a strong gate bias dependence. The p-channel hole mobility is lower with a maximum value of 2 ϫ 10 −5 cm 2 / V s. The n-and p-channel operations are characterized by a low ͑ϳ͉3͉ V͒ and a high ͑ϳ͉50͉ V͒ switch-on voltage, respectively, with the on-off current ratio on the order of 10 4 for both channels. Although the present findings are qualitatively similar to those reported previously for C 60 -methanofullerene-based transistors, ͓70͔PCBM devices are more stable and easier to reproduce. By making use of this property we are able to demonstrate functional unipolar and complementarylike logic circuits with promising operating characteristics.

Soluble fullerene derivatives: The effect of electronic structure on transistor performance and air stability

“…The graph shows two distinct regions, which shall be referred to as the moderate temperature (350 K > T > 200 K) and low temperature (T < 200 K) regions. The linear fit to the moderate temperature region is indicative of thermally-activated hopping transport and has been observed previously in both soluble fullerenes 47,48 and evaporated C 60 films. 49 The low temperature regime, where the current becomes almost temperature independent, is typically attributed to transport dominated by tunneling.…”

Air-stable ambipolar organic transistors

“…10 Realization of ambipolar organic OFETs based on a single semiconductor, on the other hand, has been proven to be much more difficult mainly due to the poor environmental stability of the n-channel operation. 1,5,9,11,12 Only recently single component air-stable ambipolar OFETs and logic circuits have been demonstrated. 4,13 In these studies the near infrared absorbing dithiolene derivative bis ͓4-dimethylaminodithiobenzyl͔-nickel was employed as the semiconductor layer.…”

“…In recent years ambipolar transport has been exploited in organic field-effect transistors ͑OFETs͒ for the fabrication of complementarylike logic circuits [1][2][3][4][5] and bifunctional devices such as lightemitting OFETs. [6][7][8][9] The majority of ambipolar organic transistors demonstrated so far are based on bulk heterojunction systems where an electron transporting ͑n-channel͒ material is mixed/blended with a hole transporting ͑p-channel͒ one, either through solution blending 1,2 or thermal coevaporation, 8 to form the heterogeneous ambipolar semiconductive layer.…”

Hydrogenation of Fullerene C60: Material Design of Organic Semiconductors by Computation

“…Although ambipolar transport in [6,6]-phenyl-C 71 -butyric acid methyl ester ([70]PCBM) was reported recently, its hole mobility (2×10 −5 cm 2 V −1 s −1 ) is much smaller than its electron mobility (2×10 −3 cm 2 V −1 s −1 ) [26]. Therefore, the enhancement of hole mobility is necessary for the practical use of fullerene derivatives as ambipolar transistor materials.…”