Origin of the Strong Induced Chiroptical Effect in Semiconducting Polymer/Helicene Blends
Lead Research Organisation:
University of Sheffield
Department Name: Materials Science and Engineering
Abstract
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People |
ORCID iD |
Xiangbing Zeng (Principal Investigator) | |
Goran Ungar (Co-Investigator) |
Publications
Chen C
(2020)
Chirality Induction through Nano-Phase Separation: Alternating Network Gyroid Phase by Thermotropic Self-Assembly of X-Shaped Bolapolyphiles.
in Angewandte Chemie (International ed. in English)
Cheng H
(2018)
Trigonal columnar self-assembly of bent phasmid mesogens.
in Chemical communications (Cambridge, England)
Fall W
(2019)
An Ising transition of chessboard tilings in a honeycomb liquid crystal
in Molecular Systems Design & Engineering
Fall WS
(2018)
Molecular ejection transition in liquid crystal columns self-assembled from wedge-shaped minidendrons.
in Soft matter
Huang N
(2021)
Self-organisation of rhombitruncated cuboctahedral hexagonal columns from an amphiphilic Janus dendrimer
in Molecular Physics
Kobayashi T
(2021)
Gyroid-Nanostructured All-Solid Polymer Films Combining High H+ Conductivity with Low H2 Permeability.
in Macromolecular rapid communications
Kobayashi T
(2019)
Gyroid structured aqua-sheets with sub-nanometer thickness enabling 3D fast proton relay conduction.
in Chemical science
Lehmann A
(2018)
Transition between tangential and co-axial liquid crystalline honeycombs in the self-assembly of Y-shaped bolapolyphiles.
in Chemical communications (Cambridge, England)
Li Y
(2022)
A case of antiferrochirality in a liquid crystal phase of counter-rotating staircases
in Nature Communications
Li YX
(2019)
New Type of Columnar Liquid Crystal Superlattice in Double-Taper Ionic Minidendrons.
in Chemistry (Weinheim an der Bergstrasse, Germany)
Title | A cover picture for Chemistry A European Journal |
Description | A new approach aimed at widening the range and complexity of potential mesophases by introducing double-taper shaped molecules is reported. In such molecules based on simple model minidendrons, a new type of hexagonal columnar liquid-crystal superlattice consisting of two kinds of columns, ionic and non-ionic, has been obtained. This points the way to creating complex self-assembly of mixed columns, mixed spheres, or mixed columns and spheres, and novel materials with double functionality. |
Type Of Art | Artwork |
Year Produced | 2019 |
Impact | Increased readership of the particular paper of ours. |
URL | https://onlinelibrary.wiley.com/doi/full/10.1002/chem.201904203 |
Title | Cover image for W.S.Fall et al, Soft Matter, 2019, 15, 22. |
Description | Artistic impression of the molecular ejection transitions in columnar LCs. |
Type Of Art | Image |
Year Produced | 2019 |
Impact | Promoting the findings in the publication to a wider audience. |
URL | https://pubs.rsc.org/en/content/articlepdf/2019/sm/c8sm01851k |
Title | Cover image for paper A. Lehmann et al. ChemComm 2018, 54, 12306. |
Description | A cover image showing the molecular models of different phases formed by Y-shaped molecules and their transitions, with the POM pictures of the phases as the background. |
Type Of Art | Image |
Year Produced | 2018 |
Impact | Promoting the findings in the publication to a wider audience. |
URL | https://pubs.rsc.org/en/content/articlepdf/2018/cc/c8cc06281a |
Description | The key development so far is that we have established the processing conditions that would maximize the chiral-optical properties of the polymer films doped with chiral dopant, including the control of dopant concentration, film thickness and most importantly, thermal annealing temperature and time. Unprecedentedly high CD (Circular Dichroism) properties in such thin film samples, that they absorb left-handed and right-handed circular polarized light very differently, have been realized. We are also coming to a better understanding the structural origin of such strong induced chiral-optical properties, and how it can be controlled in the thermal annealing process. We have further identified different crystalline phases F8BT polymers could form and how their formation can be controlled by their preparation and thermal history. The different behaviour, and different phases shown, in bulk and in thin films have been recognized. The key to the best chiroptical behaviour relies on the propagation of chiral order, which can only be achieved by annealing above the glass transition of the polymer, from a homogeneously mixed polymer/helicene system. Crystallization reduces the chiral order, so prolonged thermal annealing which leads to crystallization should be avoided. |
Exploitation Route | The extremely high CD properties of the film can be made into filters of left- or right-handed Circular polarized light for applications. We are currently working with our collaborators to fabricate organic OLEDs on the basis of such films, with the potential of emitting pure circularly polarized light. This should have vast translational potential in photonic technologies, including optical communication, quantum-based optical computing, as highly efficient liquid crystal display (LCD) backlights, and in active matrix OLED (AMOLED) displays. For example, current AMOLED displays employ a circular polarising filter (consisting of a linear polariser and quarter wave plate/film) to improve contrast by reducing external reflected light. However, nearly 50% of the transmitted light from the OLED emission is cut out by the filter, dramatically reducing overall display efficiency. An electroluminescent material that directly emits circularly polarised light will result in lower losses in brightness at the filter, and improve both efficiency and lifetime. |
Sectors | Chemicals,Digital/Communication/Information Technologies (including Software),Electronics |
Description | Spontaneous Induction and Amplification of Macroscopic Homochirality in Isotropic Liquid and Liquid Crystals |
Amount | £412,149 (GBP) |
Funding ID | EP/T003294/1 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 02/2020 |
End | 02/2023 |
Description | Imperial College London, Department of Physics and Department of Chemistry |
Organisation | Cambridge Display Technology |
Country | United Kingdom |
Sector | Private |
PI Contribution | We are working on investigating the various crystalline/liquid crystalline polymorphs present in the semiconducting polymers, and how they are affected by doping and processing conditions. These involves detailed XRD studies, on bulk, thin film and fibre samples, a lot of times involve the use of synchrotron radiation sources. Molecular modelling, simulation of diffraction patterns are also included. In addition, synchrotron radiation CD spectroscopy which enables direct in-situ observation of development of chirality in doped thin films, will be carried out as well. In the future, samples prepared in device configuration will be studied in full detail as well. |
Collaborator Contribution | Our collaborators at Department of Physics, ICL will investigate the sample preparation conditions and their effect on the device properties such as CP electro-luminescences. Constant discussions between us helps us to find the best route to prepare low-cost high quality CP emitting devices. Partners from Department of Chemistry ICL provide us with helicene and other chiral dopants for the project. CDT supplies us with semiconducting polymers of different molar mass and dispersity. |
Impact | Helicene compounds have been synthesized and provided by our collaborator. Initial combined CD and XRD studies have clarified the origin of the induced chirality in semi-conducting polymers, that it is the formation of a particular crystalline structure, presumely chiral but in pure compound it is a racemic mixture, and the inclusion of chiral dopants serving as nucleation agents and so either left- or right-handed version of the crystal dominates. |
Start Year | 2017 |
Description | Imperial College London, Department of Physics and Department of Chemistry |
Organisation | Imperial College London |
Department | Department of Chemistry |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We are working on investigating the various crystalline/liquid crystalline polymorphs present in the semiconducting polymers, and how they are affected by doping and processing conditions. These involves detailed XRD studies, on bulk, thin film and fibre samples, a lot of times involve the use of synchrotron radiation sources. Molecular modelling, simulation of diffraction patterns are also included. In addition, synchrotron radiation CD spectroscopy which enables direct in-situ observation of development of chirality in doped thin films, will be carried out as well. In the future, samples prepared in device configuration will be studied in full detail as well. |
Collaborator Contribution | Our collaborators at Department of Physics, ICL will investigate the sample preparation conditions and their effect on the device properties such as CP electro-luminescences. Constant discussions between us helps us to find the best route to prepare low-cost high quality CP emitting devices. Partners from Department of Chemistry ICL provide us with helicene and other chiral dopants for the project. CDT supplies us with semiconducting polymers of different molar mass and dispersity. |
Impact | Helicene compounds have been synthesized and provided by our collaborator. Initial combined CD and XRD studies have clarified the origin of the induced chirality in semi-conducting polymers, that it is the formation of a particular crystalline structure, presumely chiral but in pure compound it is a racemic mixture, and the inclusion of chiral dopants serving as nucleation agents and so either left- or right-handed version of the crystal dominates. |
Start Year | 2017 |
Description | Imperial College London, Department of Physics and Department of Chemistry |
Organisation | Imperial College London |
Department | Department of Physics |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | We are working on investigating the various crystalline/liquid crystalline polymorphs present in the semiconducting polymers, and how they are affected by doping and processing conditions. These involves detailed XRD studies, on bulk, thin film and fibre samples, a lot of times involve the use of synchrotron radiation sources. Molecular modelling, simulation of diffraction patterns are also included. In addition, synchrotron radiation CD spectroscopy which enables direct in-situ observation of development of chirality in doped thin films, will be carried out as well. In the future, samples prepared in device configuration will be studied in full detail as well. |
Collaborator Contribution | Our collaborators at Department of Physics, ICL will investigate the sample preparation conditions and their effect on the device properties such as CP electro-luminescences. Constant discussions between us helps us to find the best route to prepare low-cost high quality CP emitting devices. Partners from Department of Chemistry ICL provide us with helicene and other chiral dopants for the project. CDT supplies us with semiconducting polymers of different molar mass and dispersity. |
Impact | Helicene compounds have been synthesized and provided by our collaborator. Initial combined CD and XRD studies have clarified the origin of the induced chirality in semi-conducting polymers, that it is the formation of a particular crystalline structure, presumely chiral but in pure compound it is a racemic mixture, and the inclusion of chiral dopants serving as nucleation agents and so either left- or right-handed version of the crystal dominates. |
Start Year | 2017 |