Structural Nanoprobes of Organic Semiconductor Devices
Lead Research Organisation:
University of Cambridge
Department Name: Physics
Abstract
Organic semiconductors are an exciting new class of material that combine the electronic properties traditionally only associated with inorganic materials, with the mechanical properties and processibility of polymers (plastics) and small organic molecules. In particular, the ability to process active semiconductor layers through solution processing has led to the commercialisation of organic light-emitting diode-based displays. Commercial potential has also been demonstrated by organic transistors and organic solar cells, where both technologies have the advantage of low-cost processing and the ability to be incorporated into flexible architectures.However, as organic semiconductors are a relatively new class of material, there are still many fundamental questions governing key processes that affect device performance. For example, organic semiconductor films are typically less ordered than their inorganic counterparts and the influence of domain structure, molecular orientation and molecular alignment on charge transport is not fully understood. Additionally, for organic solar cells, where typically two different materials are blended together to form efficient networks for charge separation and transport, the influence of material mixing on charge separation and transport are still being discovered.Since organic semiconductors have vastly different properties compared to inorganic semiconductors, the development and application of new techniques to probe the properties of this new class of material is required. This research programme will adapt state-of-the-art microscopes and utilize advanced X-ray analytical techniques to probe structure and device action in organic devices with unprecedented precision and clarity. This further understanding of device operation will allow for the identification of physical processes that limit device performance and hence promote future device optimisation.
Publications
Collins B
(2010)
Molecular Miscibility of Polymer-Fullerene Blends
in The Journal of Physical Chemistry Letters
Brenner T
(2011)
Phase-Dependent Photocurrent Generation in Polymer/Fullerene Bulk Heterojunction Solar Cells
in The Journal of Physical Chemistry C
Brenner T
(2011)
Spatially Resolved Spectroscopic Mapping of Photocurrent and Photoluminescence in Polymer Blend Photovoltaic Devices
in The Journal of Physical Chemistry C
GĂ©linas S
(2011)
The Binding Energy of Charge-Transfer Excitons Localized at Polymeric Semiconductor Heterojunctions
in The Journal of Physical Chemistry C
He X
(2014)
Influence of Fluorination and Molecular Weight on the Morphology and Performance of PTB7:PC 71 BM Solar Cells
in The Journal of Physical Chemistry C
Gann E
(2014)
Near-edge X-ray absorption fine-structure spectroscopy of naphthalene diimide-thiophene co-polymers.
in The Journal of chemical physics
Swaraj S
(2009)
The utility of resonant soft x-ray scattering and reflectivity for the nanoscale characterization of polymers
in The European Physical Journal Special Topics
Hwang I
(2014)
Evolution of phase separation upon annealing and the influence on photocurrent generation in ternary blend organic solar cells
in Synthetic Metals
He X
(2012)
Studying polymer/fullerene intermixing and miscibility in laterally patterned films with X-ray spectromicroscopy.
in Small (Weinheim an der Bergstrasse, Germany)
McNeill CR
(2010)
Structure of phase-separated ferroelectric/semiconducting polymer blends for organic non-volatile memories.
in Small (Weinheim an der Bergstrasse, Germany)
Flesch H
(2009)
Charge transport properties and microstructure of polythiophene/polyfluorene blends
in Organic Electronics
Friedel B
(2011)
Influence of solution heating on the properties of PEDOT:PSS colloidal solutions and impact on the device performance of polymer solar cells
in Organic Electronics
Collins BA
(2012)
Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films.
in Nature materials
McNeill C
(2008)
Evolution of the nanomorphology of photovoltaic polyfluorene blends: sub-100 nm resolution with x-ray spectromicroscopy
in Nanotechnology
Swaraj S
(2010)
Nanomorphology of bulk heterojunction photovoltaic thin films probed with resonant soft X-ray scattering.
in Nano letters
Campbell AR
(2008)
Low-temperature control of nanoscale morphology for high performance polymer photovoltaics.
in Nano letters
Marsh RA
(2008)
A unified description of current-voltage characteristics in organic and hybrid photovoltaics under low light intensity.
in Nano letters
McNeill C
(2009)
Evolution of Laterally Phase-Separated Polyfluorene Blend Morphology Studied by X-ray Spectromicroscopy
in Macromolecules
Burke K
(2009)
Role of Solvent Trapping Effects in Determining the Structure and Morphology of Ternary Blend Organic Devices
in Macromolecules
Schuettfort T
(2011)
Surface and Bulk Structural Characterization of a High-Mobility Electron-Transporting Polymer
in Macromolecules
Friedel B
(2009)
Effects of Layer Thickness and Annealing of PEDOT:PSS Layers in Organic Photodetectors
in Macromolecules
Collins B
(2011)
Fullerene-Dependent Miscibility in the Silole-Containing Copolymer PSBTBT-08
in Macromolecules
Watts B
(2010)
Simultaneous Surface and Bulk Imaging of Polymer Blends with X-ray Spectromicroscopy.
in Macromolecular rapid communications
Zhang F
(2013)
Critical role of alkyl chain branching of organic semiconductors in enabling solution-processed N-channel organic thin-film transistors with mobility of up to 3.50 cm² V(-1) s(-1).
in Journal of the American Chemical Society
Schuettfort T
(2013)
Observation of a distinct surface molecular orientation in films of a high mobility conjugated polymer.
in Journal of the American Chemical Society
Description | This EPSRC Advanced Fellowship for Dr Chris McNeill allowed him to develop a series of advanced structural probes, including synchrotron-based techniques, for characterisation of the microstructure of polymer electronics devices, particularly transistors and solar cells. Combined with device physics studies, this work has furthered our understanding of charge transport and photophysics relevant to improving device performance. |
Exploitation Route | The work will inform the optimisation of practical organic electronic devices, and provides structural probes that are of interest to researchers in other fields. |
Sectors | Electronics Energy |
Description | The findings have assisted in the optimisation of polymer solar cells and transistors, accelerating their commercial application. |
First Year Of Impact | 2010 |
Sector | Electronics,Energy |
Impact Types | Economic |