Chemistry Reference
In-Depth Information
even among other nondynamic approaches such as controlled crystallisations
and so forth.
On the other hand, long-term stability and electronic robustness of gels and
xerogel films is an issue that needs further investigation. We have seen that a
controlled peeling process can be conducted on doped xerogel samples with a
conductive AFM configuration.
116
Furthermore, a clear understanding of the
gelator assembly at the nanoscale level is still required, which undoubtedly will
lead to new advanced functions. For example, it is expected that in organic
solar-cell technologies the gel approach would lead to novel and effective
molecular bulk heterojunctions with optimal charge separation, where donor-
acceptor interfaces would be considerably extended. Low-cost and flexible bulk
heterojunctions photovoltaic devices with high performance are anticipated.
Relevantly, very few examples exist in the literature where gel-based organic
solar cells are considered and relatively discrete device performances have been
achieved so far. The postassembly covalent linking of gel materials, which may
also lead to stable aerogels from molecular components, is an interesting
possibility in order to improve the applicability of gel systems. It has already
been shown that gels formed by porphyrin derivatives incorporating diacety-
lene units in the side chains next to the hydrogen-bonding group can be used to
trap the organisation by polymerisation.
158
Disulfide formation
159
or more
traditional sol-gel chemistry can also be used.
160
The proof that this paradigm
could be used to generate electronically useful materials for information pro-
cessing or sensing functions is an attractive prospect. The role of molecular
metallogels is likely to be increasingly exploited in this sense.
83-85
Clearly, many challenges remain in this nascent field of research. Therefore,
and even though great advance has been made, new breakthrough research and
further knowledge are required to properly design future emerging technologies
with gel-based materials. Nonetheless, the promise offered by the gel approach
in the coming years is immense, a myriad of applications extending beyond the
ones shown here are likely.
Acknowledgements
We are indebted to the institutions that fund our research in this area under
projects RYC-2011-08071, 2009 SGR 158 and CTQ2010-16339.
References
1. J. W. Steed, P. A. Gale (ed.), Supramolecular Chemistry: FromMolecules to
Nanomaterials, Wiley-VCH, Weinheim, 2012, ISBN: 978-0-470-74640-0.
2. A. Dawn, T. Shiraki, S. Haraguchi, S. Tamaru and S. Shinkai, Chem.
Asian J., 2011, 6, 266.
3. T. J. Barton, L. M. Bull, W. G. Klemperer, D. A. Loy, B. McEnaney,
M. Misono, P. A. Monson, G. Pez, G. W. Scherer, J. C. Vartuli and
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