Annual Report 2007 - The Australian Nanotechnology Network

In an effort to confirm the presence of the Ru 3+ species within the RuPMAS composite that was
hypothesised after examining the ESR data obtained in UoW, bulk electrolysis of the composite films was
preformed. The resultant spectra relieved the presence of the Ru 3+ absorption band emerging while the
sample was under photoirradiation. In conjunction with the ESR data, this does confirm a photo-driven
electron transfer process between the ruthenium metal centre and the conducting polymer backbone.
This body of work in combination with the ESR investigations preformed in UoW is described in a paper,
which once corrected will be submitted for publication.
To complement this research, a potential controlled experiment was preformed, although the data has yet
to be completely analysed and plotted. The potential control was also utilised to examine the electron
transfer mechanisms involved in the generation of ECL, which is a continuing collaborative research
project between the two Centres of Excellence. To obtain a more in depth understanding of these
mechanisms, Raman spectroscopy was also utilised and by combining both these techniques a complete
picture will hopefully be obtained. This investigation will hopefully be submitted for publication referencing
previous work on these composite films acknowledging funding support from the ARCNN and ARC.
Unfortunately, only the overall excited state lifetimes could be determined and as such both the SPC and
FLIM analysis of these films were comparable within experimental error. The investigation into these
films, did show some quenching of the emission, as stated above. However, the lifetime quenching could
not be determined for the solid-state samples.
During this trip, the imaging and spectroscopic characterisation of polyaniline (Pani) nanofibres was
studied. The fluorescent imaging utilising the FLIM closely related back to the TEM images obtained
during the synthesis of these fibres. The spectroscopic analysis didn’t reveal anything unusual from the
fibres and closely resembled that of Pani films, with similar UV-Vis and luminescent properties. This was
also true of the polypyrrole nanofibres. Despite this the polypyrrole nanofibres are currently undergoing
preliminary investigations, preformed with Karl Crowley and Aoife Morrin from Malcolm Symth’s research
group, to evaluate their possible use within a chemical sensor.
With the Ru-Pani and Pani nanofibres a potential controlled investigation was also completed. This did
not prove successful. The Pani component of both types of nanofibre was electrochemically active over
the potential range, -200 to 600 mV, however, above this potential the Pani was oxidised and the
nanofibre destroyed. Even on initial scans, the degradation to the Pani structure prevented the redox
couple of the ruthenium metal centre from being observed. The presence of the ruthenium could only be
confirmed spectroscopically. This observation limits the usefulness of the Ru-Pani nanofibre for any
electrochemical application.
To complete some of the spectroscopic analysis of two separate research projects carried out in UoW,
the SPC was utilised to obtain excited state lifetimes of polyazane/Pani solutions and HMWT PMAS
solutions in DMSO. The observed lifetimes were in agreement with the earlier spectroscopic data
recorded in Wollongong and will be used within any reports or publications of this body of work.
Career and Skills Developments
During this trip I received excellent training on numerous analytical techniques including the FLIM and
SPC. This expertise will be transferred to my colleagues in the IPRI. This training not only incorporated
49