SONSEUROCORES - Self Organised Hybrid Devices (SOHYD)

Lead Research Organisation: Imperial College London
Department Name: Chemistry

Abstract

Molecular electronics is emerging as a powerful technology platform and is an area that is recognised as one of the recent European success stories in science. It combines many of the attributes of present day electronics and optoelectronics with attractive possibilities for control of functionality at the molecular level. Important advantages of molecules are their versatility in design of electronic properties, their dimensions, and their organization by self-assembling techniques to obtain self-assembled monolayers (SAMs) or functional domains . In these nanostructures one has the possibility to combine active electronic components with passive ones as for example electronic conductors with insulators, or molecular assemblies with different refractive indexes for light guiding modes . Of particular interest is the development of devices using supra- and super-molecular self-organized architectures, where the limited functionalities of individual molecular components are enhanced by their organization into larger super molecular systems. Although, rapid progress has been made in the fields of supra molecular and super molecular chemistry, including the demonstrations of redox switches and light driven molecular machines it is striking that there are still only few examples of technological applications in this field . There are two key factors behind the lack of technological exploitation of such complex architectures. Firstly, whilst enhanced functionality of super molecular structures has been widely demonstrated in solution, the integration of such super molecular structures into solid state electronic or optoelectronic devices has been very limited to date . Secondly, and more importantly, there still remains a basic lack of understanding between the molecular entity and the self-organized materials structure, as well as its function in molecular electronic devices. These issues are of fundamental interest and essential to the development of 'next generation' molecular electronic and hetero supra molecular devices. This project will aim to address these issues and investigate optical and electrical phenomena arising in well defined nano-structured assemblies. We aim to explore the potential of these nanostructured assemblies in electronic device applications such as solar cells, field-effect transistors and light emitting diodes. To turn this aim into reality we will conduct a multidisaplinary research program involving novel nanomaterials synthesis, functional characterization (laser based optical pump-prope spectroscopy), and electrical device fabrication and testing.

Publications

10 25 50
 
Description Summary:

SOHYDs was a highly multidisciplinary project and collaborative effort involving research groups from United Kingdom, Spain, Germany, Switzerland and Belgium. The project focused on the basic science relating to the function and development of self-organized nanomaterials for electronic devices. A key aim of this project was to bring organic and inorganic chemists, who have expertise in synthesising and developing new self-organising molecular structures based on chemical and biological motifs, together with physical chemists and physicists, who have expertise in developing and evaluating novel hetero-supermolecular functionalities and devices. Included within the combined skills set are expertise in inorganic, organic and polymeric semiconductor synthesis and processing, fundamental materials characterisation, device fabrication and testing, device physics and modelling, project management and technology transfer. This combination of expertises has resulted in several excellent scientific contributions of which a selection is presented.

1. Charge separation and recombination in self-organizing nanostructured donor-acceptor block copolymer films. This work has shown that donor - acceptor block copolymers can be used to control both the nanomorphology and the charge photogeneration on yields. We have also demonstrated that the use of donor-acceptor block copolymers (compared to random blends) can be used to improve the performance of photovoltaic devices. A key parameter controlling charge generation yield is the molecular weight of the block copolymer. Specifically, this work focuses on the development of quantitative structure function relationships that can be used to rationally design self-organizing molecular materials for photovoltaic device applications.

2. Reducing charge recombination losses in solid state dye sensitized solar cells: the use of donor-acceptor sensitizer dyes.
This work shows that a key parameter controlling the dynamics of charge recombination in dye sensitized metal oxide films is the spatial separation between the metal oxide surface and the dye cation moiety on the dye. This work has facilitated the rational design and synthesis of molecular dyes for efficient dye sensitized solar cells. Specifically, in this work we have demonstrated that such supermolecular dye can be used to control charge recombination losses at the metal oxide / dye / organic hole conductor interface and lead to a 25% improvement in device performance. It has been highlighted in Chemical Technology: (http://www.rsc.org/Publishing/ChemTech/Volume/2007/05/super_solar_cells.asp). The paper has been citied 18 times. This work has stimulated several scientists to use this concept to improve the efficiency of solid state dye sensitized solar cells.

3. Development of light emitting diodes based upon a nanostructured hybrid metal oxide / polymer films. These new devices offer the potential of both improved performance and lifetime. This work has also contributed to the fundamental understanding of light emitting diode function.

4. CdSe quantum dot-sensitized solar cells exceeding efficiency 1% at full-sun intensity. This research has led to a better understanding of the mechanisms of charge generation at quantum dot / metal oxide interfaces. Specifically, in this work we have developed a new cobalt-complex based redox couple for use with quantum dot sensitizers.

Publications:

1. *N. Tokmoldin, N. Griffiths, D. D. C. Bradley, S. A. Haque, A hybrid inorganic- organic semiconductor light emitting diode using ZrO2 as an electron injection layer, Adv. Mater (2009), 21, 1-4, DOI: 10.1002/adma.200802594 (2008 Impact factor = 8.2)
2. *S. King, M. Sommer, S. Huetter, M. Thelakkat and S. A. Haque. Charge separation and recombination in self-organizing nanostructured donor- acceptor block copolymer films, J. Mater. Chem. (2009), 19, 5436-5441
3. *H. Leventis, S. A. Haque, Control of charge recombination at nanostructured quantum-dot sensitized TiO2 interfaces employing a multi-step redox cascade, Energy and Environmental Science, (2009) DOI:10.1039/B911527G (2008)
4. *S. Handa, H. Wietasch, M. Thelakkat, J. R. Durrant, S. A. Haque. Reducing charge recombination losses in solid state dye sensitized solar cells: the use of donor-acceptor sensitizer dyes. Chem. Commun. (2007), 17, 1725- 1727 (2008 Impact factor = 5.3)
5. *H. Lee. H. C. Leventis, S. J. Moon, P. Chen, S. Ito, S. A. Haque, T. Torres, F. Nuesch, T. Geiger, S. M. Zakeeruddin, M. Graetzel, M. K. Nazeeruddin, PbS and CdS quantum dot sensitized solid state solar cells: "old concepts, New results", Adv. Func. Mater. (2009), 19, 2735-2742
6. *H. J. Lee, J. H. Yum, H. C. Leventis, S. M. Zakeeruddin, S. A. Haque, P. Chen, S. I. Seok, M. Graetzel and M. K. Nazeeruddin. CdSe quantum-dot sensitized solar cells exceeding 1% at full-sun intensity, J. Phys. Chem. C. (2008), 112, 11600-11608.
7. *C. C. Hofmann, P. Bauer, S. A. Haque, M. Thelakkat, J. Kohler; Energy and charge transfer processes in flexible organic donor-acceptor dyads; Journal of chemical Physics, 131, 144512 (2009)
8. *C. C. Hofmann, S. Lindner, M. Ruppert, A. Hirch, S. A. Haque, M. Thelakkat, J. Kohler; The Mutual Interplay of Light Harvesting and Triplet Sensitizing in a Perylene Bisimide-Antenna Fullerene Dyad; Journal of Physical Chemistry, (2010 in press)
9. *S. King, M. Sommer, S. Huetter, M. Thelakkat and S. A. Haque. The influence of post-fabrication annealing and polymer crystallinity on the morphology and interfacial charge transfer dynamics in nanostructured donor-acceptor block copolymer solar cells, J. Am. Chem. Soc. (2010), manuscript submitted
10.10.O'Regan, B. C., and Durrant, J. R. (2009) Accounts of Chemical Research 42,1799-180811.*Morandeira, A., Lopez-Duarte, I., O'Regan, B., Martinez-Diaz, M. V., Forneli, A., Palomares, E., Torres, T., and Durrant, J. R. (2009) Journal of Materials Chemistry 19, 5016-5026
12.*O'Regan, B. C., Lopez-Duarte, I., Martinez-Diaz, M. V., Forneli, A., Albero, J., Morandeira, A., Palomares, E., Torres, T., and Durrant, J. R. (2008) Journal of the American Chemical Society 130, 2906-2907
13.*S. M., Gratzel, M., Hinsch, A., Hore, S., Wurfel, U., Sastrawan, R., Durrant, J. R., Palomares, E., Pettersson, H., Gruszecki, T., Walter, J., Skupien, K., and Tulloch, G. E. (2007) Progress in Photovoltaics 15, 1
14.*Morandeira, A., Lopez-Duarte, I., Martinez-Diaz, M. V., O'Regan, B., Shuttle, C., Haji-Zainulabidin, N. A., Torres, T., Palomares, E., and Durrant, J. R. (2007) Journal of the American Chemical Society 129, 9250-+
15.*Clifford, J. N., Palomares, E., Nazeeruddin, M. K., Gratzel, M., and Durrant, J. R. (2007) Journal of Physical Chemistry C 111, 6561-6567
Exploitation Route The scientific and technological advances in this project have been provided above. These findings should help advance the current fundamental understanding of device operation mechanisms in optoelectronic device technology e.g. solar cells and should lead to advances in device performance.

Additionally it is pertinent to note that the findings of this research project have led to number of publications as indicated in key findings section. This project has also led to continued collaboration between research partners and in some cases further funding.
Sectors Chemicals

Electronics

Energy

Environment

 
Description The findings of this research project have led to number of publications as indicated in key findings section. This project has also led to continued collaboration between research partners and in some cases further funding.