Apertureless scanning near-field optical studies of energy and charge transfer in molecular materials for opto-electronic devices.
Lead Research Organisation:
University of Sheffield
Department Name: Physics and Astronomy
Abstract
The development of highly efficient electronic devices is a major goal of molecular electronics. To achieve this we need to fully understand how energy is passed from one molecule to another. Theoretically this is a simple problem to understand for two small molecules. However, in electronic devices made from blends of semi-conducting polymers energy transfer occurs at the boundaries between different polymer domains. At these boundaries many processes that occur on length scales of several nanometres can play an important role in the efficiency of the energy transfer process. To study the effect these processes have on device efficiency, I aim to develop an apertureless scanning near field microscope (A-SNOM). This microscope will allow me to study the optical properties of a variety of materials at a resolution high enough to resolve individual molecules.Using the A-SNOM I will study a variety of opto-electronic systems based on conjugated polymers. Firstly I will study blends of conjugated polymers. These polymers can be blended with other polymers or small molecules and be used as the active material in light emitting diodes or photo-voltaic devices. This will lead to a greater understanding of energy transfer in these systems and can be used to improve the efficiency of devices based on blends of conjugated polymers. The second group materials I will study will consist of light harvesting complexes (LHC) derived from specialised bacteria combined with conjugated polymers, in order that the polymers protect the bacteria while facilitating energy transfer from the polymer to the bacteria. This will represent one of the first nanoscale studies of the use of bacterial compounds in molecular electronics. Finally the A-SNOM will be used to study small numbers of interacting molecules. The high resolution of A-SNOM will allow me to image the optical properties of single molecules acting as either (energy) donor or acceptor molecules. This can be used to improve our understanding in the electronic interactions between these molecules. Studying single molecules (or two interacting molecules) will be of interest to theoreticians and will shed light on processes that occur in real devices. This is not possible using other conventional measurement techniques. Finally it will also be possible to directly correlate a molecules morphology with its energy transfer ability. The A-SNOM will allow me to make simultaneous measurements of a molecules morphology and optical properties. The results from these studies will be used in conjunction with a model photovoltaic device which will permit me to understand fundamental process which limit device performance. The device will consist of patterned strips of alternating low and high bang-gap polymers. It will be possible to incorporate results obtained during the studies outlined above to increase device efficiency.
People |
ORCID iD |
Ashley Cadby (Principal Investigator) |
Publications
Wang L
(2012)
Highly confined surface imaging by solid immersion total internal reflection fluorescence microscopy.
in Optics express
Tsoi W
(2008)
Observation of the ß -Phase in Two Short-Chain Oligofluorenes
in Advanced Functional Materials
Higgins A
(2008)
The Impact of Interfacial Mixing on Förster Transfer at Conjugated Polymer Heterojunctions
in Advanced Functional Materials
Adams PG
(2013)
Comparison of the physical characteristics of chlorosomes from three different phyla of green phototrophic bacteria.
in Biochimica et biophysica acta
Description | In this work we discovered new techniques to improve the optical resolution of optical microcopy. Specifically we can trace, with very high precision, the flow of energy through single nano wires. |
Exploitation Route | This work is now being applied to the study of energy transfer in light harvesting protein structures. |
Sectors | Electronics Energy Manufacturing including Industrial Biotechology |
Description | Active Filter for tip enhanced Microscopy |
Amount | £40,000 (GBP) |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 01/2012 |
End | 01/2013 |
Description | Active Filter for tip enhanced Microscopy |
Amount | £40,000 (GBP) |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 01/2012 |
End | 06/2013 |
Description | Novel STORM microscope |
Amount | £75,000 (GBP) |
Organisation | Higher Education Funding Council for England |
Sector | Public |
Country | United Kingdom |
Start | 01/2012 |
End | 01/2013 |
Description | Novel STORM microscope |
Amount | £75,000 (GBP) |
Organisation | Higher Education Funding Council for England |
Sector | Public |
Country | United Kingdom |
Start | 01/2012 |
End | 05/2012 |
Description | Storm Force Microscopy |
Amount | £120,000 (GBP) |
Funding ID | BB/I023518/1 |
Organisation | Biotechnology and Biological Sciences Research Council (BBSRC) |
Sector | Public |
Country | United Kingdom |
Start | 09/2011 |
End | 09/2012 |
Description | Andor |
Organisation | Andor Technology |
Country | United Kingdom |
Sector | Private |
PI Contribution | We have worked closely with Andor over a number of years. We have helped them informally process data and given them an understanding of the application of their technologies to the Bio-Physics community. I have spent time at Andor as part of an Industrial Sabbatical. |
Collaborator Contribution | Andor have provided us with extra cameras when needed and also given a couple of extra cameras to us. |
Impact | I have spent time at Andor as part of an Industrial Sabbatical. |
Start Year | 2009 |
Description | Collaboration with Hamamatsu photonics |
Organisation | PMT Hamamatsu Photonics K.K. |
Country | Japan |
Sector | Private |
PI Contribution | Working closely with Hamamatsu we aim to help define the meaning of resolution in high resolution microscopy techniques such as STORM, PALM and SNOM. Hamamatsu invested money in to Sheffield 45K and allowed us access to its engineers and technology, which we estimate to be worth 55K. |
Start Year | 2012 |