**Acknowledgements**

**Figure 12.** Raman spectra of PEDOT film recorded all along 1 year [41].

152 Recent Research in Polymerization

both when cooling-down and warming-up the sample.

for the conductivity as reported in Eq. (1):

limited tunnelling between grains [57, 58].

*σ* = *σ*<sup>0</sup> exp[−(

Raman spectroscopy investigation, as reported in **Figure 12**.

Performances of films have been investigated also in terms of conductivity as function of temperature. **Figure 11** shows the conductivity as a function temperature in the range 130–350 K,

The good reproducibility showed that there was no structural changes in the film, and that the temperature-dependence of the conductivity was owing to the intrinsic carrier transport mechanism in the film. The observed decreasing in conductivity, while the temperature decreases, is typical for an organic conductor, where carrier transport usually occurs by hopping conduction. In order to further investigate the carrier transport mechanism, in **Figure 11b** the natural logarithm of the conductivity as a function of the inverse temperature, 1/T have been reported. It was observed a good fit with a power, implying the following dependence

*T*\_\_0

The best fit was obtained with α = 0.63 ± 0.07. This value is far from 1/4, already reported for 3D variable range hoping (VRH), far from 1, as reported for nearest neighbour hoping, and far from 1/3, as reported for 2D variable range hoping [25, 55, 56]. The value is closer to 1/2, already reported for PEDOT:PSS and which corresponds to 1D VRH or hopping in a granular material where, the exponent α for 3D VRH varies from1/4 to 1/2 due to charging energy-

Another requirement that PEDOT film has to show is the stability of the time. PEDOT films were exposed to ambient conditions over 1 year and its chemical structure was followed by

*<sup>T</sup>* )*α*] (1)

The authors wish to express their appreciation to Mr. Noureddine Adjeroud for his contribution to RT-CVD process; to Dr. Mael Guennou, Dr. Jérôme Guillot, for performed Raman and XPS analyses respectively. Aixtron SE is also acknowledge for direct technical assistance.

This work has been funded in part by Fond National de la Recherche Luxembourg (FNR Luxembourg) through INTER/NSF/MAT/11/01 'Visible Light Nanocomposite Photocatalysts (VISICAT) project, and in part by AFR call PDR 2012-2, ref 4735153.
