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
McNeill C
(2009)
Photocurrent transients in all-polymer solar cells: Trapping and detrapping effects
in Journal of Applied Physics
Marsh RA
(2008)
A unified description of current-voltage characteristics in organic and hybrid photovoltaics under low light intensity.
in Nano letters
Li Z
(2011)
Comparison of the Operation of Polymer/Fullerene, Polymer/Polymer, and Polymer/Nanocrystal Solar Cells: A Transient Photocurrent and Photovoltage Study
in Advanced Functional Materials
Li Z
(2011)
Transient photocurrent measurements of PCDTBT:PC70BM and PCPDTBT:PC70BM Solar Cells: Evidence for charge trapping in efficient polymer/fullerene blends
in Journal of Applied Physics
Li Z
(2013)
Voltage-dependent photocurrent transients of PTB7:PC70BM solar cells: Experiment and numerical simulation
in Journal of Applied Physics
Hwang I
(2014)
Evolution of phase separation upon annealing and the influence on photocurrent generation in ternary blend organic solar cells
in Synthetic Metals
Hwang I
(2009)
Drift-diffusion modeling of photocurrent transients in bulk heterojunction solar cells
in Journal of Applied Physics
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
He X
(2012)
Studying polymer/fullerene intermixing and miscibility in laterally patterned films with X-ray spectromicroscopy.
in Small (Weinheim an der Bergstrasse, Germany)
GĂ©linas S
(2011)
The Binding Energy of Charge-Transfer Excitons Localized at Polymeric Semiconductor Heterojunctions
in The Journal of Physical Chemistry C
Gwinner MC
(2012)
Highly efficient single-layer polymer ambipolar light-emitting field-effect transistors.
in Advanced materials (Deerfield Beach, Fla.)
Gwinner M
(2012)
Organic field-effect transistors and solar cells using novel high electron-affinity conjugated copolymers based on alkylbenzotriazole and benzothiadiazole
in Journal of Materials Chemistry
Gao F
(2014)
Trap-induced losses in hybrid photovoltaics.
in ACS nano
Gann E
(2014)
Near-edge X-ray absorption fine-structure spectroscopy of naphthalene diimide-thiophene co-polymers.
in The Journal of chemical physics
Friend RH
(2012)
Excitons and charges at organic semiconductor heterojunctions.
in Faraday discussions
Friedel B
(2009)
Effects of Layer Thickness and Annealing of PEDOT:PSS Layers in Organic Photodetectors
in Macromolecules
Friedel B
(2010)
Influence of Alkyl Side-Chain Length on the Performance of Poly(3-alkylthiophene)/Polyfluorene All-Polymer Solar Cells
in Chemistry of Materials
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
Flesch H
(2009)
Charge transport properties and microstructure of polythiophene/polyfluorene blends
in Organic Electronics
Dalgleish S
(2011)
Indole-substituted nickel dithiolene complexes in electronic and optoelectronic devices
in Journal of Materials Chemistry
Collins BA
(2012)
Polarized X-ray scattering reveals non-crystalline orientational ordering in organic films.
in Nature materials
Collins B
(2011)
Fullerene-Dependent Miscibility in the Silole-Containing Copolymer PSBTBT-08
in Macromolecules
Collins B
(2012)
Absolute Measurement of Domain Composition and Nanoscale Size Distribution Explains Performance in PTB7:PC 71 BM Solar Cells
in Advanced Energy Materials
Collins B
(2010)
Molecular Miscibility of Polymer-Fullerene Blends
in The Journal of Physical Chemistry Letters
Campbell AR
(2008)
Low-temperature control of nanoscale morphology for high performance polymer photovoltaics.
in Nano letters
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 |