1
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Gray V, Toolan DTW, Dowland S, Allardice JR, Weir MP, Zhang Z, Xiao J, Klimash A, Winkel JF, Holland EK, Fregoso GM, Anthony JE, Bronstein H, Friend R, Ryan AJ, Jones RAL, Greenham NC, Rao A. Ligand-Directed Self-Assembly of Organic-Semiconductor/Quantum-Dot Blend Films Enables Efficient Triplet Exciton-Photon Conversion. J Am Chem Soc 2024; 146:7763-7770. [PMID: 38456418 PMCID: PMC10958494 DOI: 10.1021/jacs.4c00125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 03/09/2024]
Abstract
Blends comprising organic semiconductors and inorganic quantum dots (QDs) are relevant for many optoelectronic applications and devices. However, the individual components in organic-QD blends have a strong tendency to aggregate and phase-separate during film processing, compromising both their structural and electronic properties. Here, we demonstrate a QD surface engineering approach using electronically active, highly soluble semiconductor ligands that are matched to the organic semiconductor host material to achieve well-dispersed inorganic-organic blend films, as characterized by X-ray and neutron scattering, and electron microscopies. This approach preserves the electronic properties of the organic and QD phases and also creates an optimized interface between them. We exemplify this in two emerging applications, singlet-fission-based photon multiplication (SF-PM) and triplet-triplet annihilation-based photon upconversion (TTA-UC). Steady-state and time-resolved optical spectroscopy shows that triplet excitons can be transferred with near unity efficiently across the organic-inorganic interface, while the organic films maintain efficient SF (190% yield) in the organic phase. By changing the relative energy between organic and inorganic components, yellow upconverted emission is observed upon 790 nm NIR excitation. Overall, we provide a highly versatile approach to overcome longstanding challenges in the blending of organic semiconductors with QDs that have relevance for many optical and optoelectronic applications.
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Affiliation(s)
- Victor Gray
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K.
- Department
of Chemistry, Ångström Laboratory, Uppsala University, Box 532, SE-751 20 Uppsala, Sweden
| | - Daniel T. W. Toolan
- Department
of Chemistry, The University of Sheffield, Sheffield S3 7HF, U.K.
- Department
of Materials, The University of Manchester, Engineering Building A, Booth Street
East, Manchester M13 9PL, U.K.
| | - Simon Dowland
- Cambridge
Photon Technology, J.
J. Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Jesse R. Allardice
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Michael P. Weir
- School of
Physics and Astronomy, The University of
Nottingham, University Park, Nottingham NG7 2RD, U.K.
| | - Zhilong Zhang
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - James Xiao
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Anastasia Klimash
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield
Road, Cambridge CB2 1EW, U.K.
| | - Jurjen F. Winkel
- Cambridge
Photon Technology, J.
J. Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Emma K. Holland
- Center
for Applied Energy Research, University
of Kentucky, Research Park Drive, Lexington, Kentucky 40511, United States
| | - Garrett M. Fregoso
- Center
for Applied Energy Research, University
of Kentucky, Research Park Drive, Lexington, Kentucky 40511, United States
| | - John E. Anthony
- Center
for Applied Energy Research, University
of Kentucky, Research Park Drive, Lexington, Kentucky 40511, United States
| | - Hugo Bronstein
- Yusuf
Hamied Department of Chemistry, University
of Cambridge, Lensfield
Road, Cambridge CB2 1EW, U.K.
| | - Richard Friend
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Anthony J. Ryan
- Department
of Chemistry, The University of Sheffield, Sheffield S3 7HF, U.K.
| | - Richard A. L. Jones
- John
Owens Building, The University of Manchester, Oxford Road, Manchester M13 9PL, U.K.
| | - Neil C. Greenham
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K.
| | - Akshay Rao
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K.
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2
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Gray V, Drake W, Allardice JR, Zhang Z, Xiao J, Congrave DG, Royakkers J, Zeng W, Dowland S, Greenham NC, Bronstein H, Anthony JE, Rao A. Triplet transfer from PbS quantum dots to tetracene ligands: is faster always better? J Mater Chem C Mater 2022; 10:16321-16329. [PMID: 36562020 PMCID: PMC9648495 DOI: 10.1039/d2tc03470k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 09/28/2022] [Indexed: 06/17/2023]
Abstract
Quantum dot-organic semiconductor hybrid materials are gaining increasing attention as spin mixers for applications ranging from solar harvesting to spin memories. Triplet energy transfer between the inorganic quantum dot (QD) and organic semiconductor is a key step to understand in order to develop these applications. Here we report on the triplet energy transfer from PbS QDs to four energetically and structurally similar tetracene ligands. Even with similar ligands we find that the triplet energy transfer dynamics can vary significantly. For TIPS-tetracene derivatives with carboxylic acid, acetic acid and methanethiol anchoring groups on the short pro-cata side we find that triplet transfer occurs through a stepwise process, mediated via a surface state, whereas for monosubstituted TIPS-tetracene derivative 5-(4-benzoic acid)-12-triisopropylsilylethynyl tetracene (BAT) triplet transfer occurs directly, albeit slower, via a Dexter exchange mechanism. Even though triplet transfer is slower with BAT the overall yield is greater, as determined from upconverted emission using rubrene emitters. This work highlights that the surface-mediated transfer mechanism is plagued with parasitic loss pathways and that materials with direct Dexter-like triplet transfer are preferred for high-efficiency applications.
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Affiliation(s)
- Victor Gray
- Cavendish Laboratory, University of Cambridge J. J. Thomson Avenue Cambridge CB3 0HE UK
- Department of Chemistry - Ångström Laboratory, Uppsala University Box 523 751 20 Uppsala Sweden
| | - William Drake
- Cavendish Laboratory, University of Cambridge J. J. Thomson Avenue Cambridge CB3 0HE UK
| | - Jesse R Allardice
- Cavendish Laboratory, University of Cambridge J. J. Thomson Avenue Cambridge CB3 0HE UK
| | - Zhilong Zhang
- Cavendish Laboratory, University of Cambridge J. J. Thomson Avenue Cambridge CB3 0HE UK
| | - James Xiao
- Cavendish Laboratory, University of Cambridge J. J. Thomson Avenue Cambridge CB3 0HE UK
| | - Daniel G Congrave
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Jeroen Royakkers
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Weixuan Zeng
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Simon Dowland
- Cambridge Photon Technology J. J. Thomson Avenue Cambridge CB3 0HE UK
| | - Neil C Greenham
- Cavendish Laboratory, University of Cambridge J. J. Thomson Avenue Cambridge CB3 0HE UK
| | - Hugo Bronstein
- Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - John E Anthony
- University of Kentucky Center for Applied Energy Research 2582 Research Park Dr Lexington Kentucky 40511 USA
| | - Akshay Rao
- Cavendish Laboratory, University of Cambridge J. J. Thomson Avenue Cambridge CB3 0HE UK
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Lee CH, Gray V, Teo JMN, Tam AR, Fong CHY, Lui DTW, Pang P, Chan KH, Hung IFN, Tan KCB, Ling GS. Comparing the B and T cell-mediated immune responses in patients with type 2 diabetes receiving mRNA or inactivated COVID-19 vaccines. Front Immunol 2022; 13:1018393. [PMID: 36304475 PMCID: PMC9592994 DOI: 10.3389/fimmu.2022.1018393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 09/26/2022] [Indexed: 12/05/2022] Open
Abstract
Acquiring protective immunity through vaccination is essential, especially for patients with type 2 diabetes who are vulnerable for adverse clinical outcomes during coronavirus disease 2019 (COVID-19) infection. Type 2 diabetes (T2D) is associated with immune dysfunction. Here, we evaluated the impact of T2D on the immunological responses induced by mRNA (BNT162b2) and inactivated (CoronaVac) vaccines, the two most commonly used COVID-19 vaccines. The study consisted of two parts. In Part 1, the sera titres of IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) alpha receptor binding domain (RBD), their neutralizing capacity, and antigen-specific CD4+T and CD8+T cell responses at 3-6 months after vaccination were compared between BNT162b2 (n=60) and CoronaVac (n=50) vaccinees with or without T2D. Part 2 was a time-course study investigating the initial B and T cell responses induced by BNT162b2 among vaccinees (n=16) with or without T2D. Our data showed that T2D impaired both cellular and humoral immune responses induced by CoronaVac. For BNT162b2, T2D patients displayed a reduction in CD4+T-helper 1 (Th1) differentiation following their first dose. However, this initial defect was rectified by the second dose of BNT162b2, resulting in comparable levels of memory CD4+ and CD8+T cells, anti-RBD IgG, and neutralizing antibodies with healthy individuals at 3-6 months after vaccination. Hence, T2D influences the effectiveness of COVID-19 vaccines depending on their platform. Our findings provide a potential mechanism for the susceptibility of developing adverse outcomes observed in COVID-19 patients with T2D and received either CoronaVac or just one dose of BNT162b2.
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Affiliation(s)
- Chi-Ho Lee
- Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Victor Gray
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Jia Ming Nickolas Teo
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Anthony Raymond Tam
- Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Carol Ho-Yi Fong
- Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - David Tak-Wai Lui
- Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Polly Pang
- Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Kwok Hung Chan
- Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Ivan Fan-Ngai Hung
- Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
- *Correspondence: Guang Sheng Ling, ; Ivan Fan-Ngai Hung, ; Kathryn Choon-Beng Tan,
| | - Kathryn Choon-Beng Tan
- Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
- *Correspondence: Guang Sheng Ling, ; Ivan Fan-Ngai Hung, ; Kathryn Choon-Beng Tan,
| | - Guang Sheng Ling
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
- *Correspondence: Guang Sheng Ling, ; Ivan Fan-Ngai Hung, ; Kathryn Choon-Beng Tan,
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4
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Martinez EG, Zuniga C, Gray V. Qualitative Evaluation of CalFresh Healthy Living (SNAP-Ed) Implementation Across Eight Universities. J Acad Nutr Diet 2022. [DOI: 10.1016/j.jand.2022.08.109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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5
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Gorman J, Orsborne SRE, Sridhar A, Pandya R, Budden P, Ohmann A, Panjwani NA, Liu Y, Greenfield JL, Dowland S, Gray V, Ryan STJ, De Ornellas S, El-Sagheer AH, Brown T, Nitschke JR, Behrends J, Keyser UF, Rao A, Collepardo-Guevara R, Stulz E, Friend RH, Auras F. Deoxyribonucleic Acid Encoded and Size-Defined π-Stacking of Perylene Diimides. J Am Chem Soc 2021; 144:368-376. [PMID: 34936763 PMCID: PMC8759064 DOI: 10.1021/jacs.1c10241] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
![]()
Natural photosystems
use protein scaffolds to control intermolecular
interactions that enable exciton flow, charge generation, and long-range
charge separation. In contrast, there is limited structural control
in current organic electronic devices such as OLEDs and solar cells.
We report here the DNA-encoded assembly of π-conjugated perylene
diimides (PDIs) with deterministic control over the number of electronically
coupled molecules. The PDIs are integrated within DNA chains using
phosphoramidite coupling chemistry, allowing selection of the DNA
sequence to either side, and specification of intermolecular DNA hybridization.
In this way, we have developed a “toolbox” for construction
of any stacking sequence of these semiconducting molecules. We have
discovered that we need to use a full hierarchy of interactions: DNA
guides the semiconductors into specified close proximity, hydrophobic–hydrophilic
differentiation drives aggregation of the semiconductor moieties,
and local geometry and electrostatic interactions define intermolecular
positioning. As a result, the PDIs pack to give substantial intermolecular
π wave function overlap, leading to an evolution of singlet
excited states from localized excitons in the PDI monomer to excimers
with wave functions delocalized over all five PDIs in the pentamer.
This is accompanied by a change in the dominant triplet forming mechanism
from localized spin–orbit charge transfer mediated intersystem
crossing for the monomer toward a delocalized excimer process for
the pentamer. Our modular DNA-based assembly reveals real opportunities
for the rapid development of bespoke semiconductor architectures with
molecule-by-molecule precision.
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Affiliation(s)
- Jeffrey Gorman
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Sarah R E Orsborne
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Akshay Sridhar
- Department of Applied Physics, Science for Life Laboratory, KTH Royal Institute of Technology, 171 21 Solna, Sweden
| | - Raj Pandya
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Peter Budden
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Alexander Ohmann
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Naitik A Panjwani
- Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Yun Liu
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Jake L Greenfield
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Simon Dowland
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Victor Gray
- Department of Chemistry, Ångström Laboratory, Uppsala University, 751 20 Uppsala, Sweden
| | - Seán T J Ryan
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Sara De Ornellas
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Afaf H El-Sagheer
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Tom Brown
- Department of Chemistry, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Jonathan R Nitschke
- Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, United Kingdom
| | - Jan Behrends
- Berlin Joint EPR Lab, Fachbereich Physik, Freie Universität Berlin, 14195 Berlin, Germany
| | - Ulrich F Keyser
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | | | - Eugen Stulz
- Department of Chemistry & Institute for Life Sciences, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Richard H Friend
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Florian Auras
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
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6
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Olesund A, Gray V, Mårtensson J, Albinsson B. Diphenylanthracene Dimers for Triplet-Triplet Annihilation Photon Upconversion: Mechanistic Insights for Intramolecular Pathways and the Importance of Molecular Geometry. J Am Chem Soc 2021; 143:5745-5754. [PMID: 33835789 PMCID: PMC8154513 DOI: 10.1021/jacs.1c00331] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Novel approaches
to modify the spectral output of the sun have
seen a surge in interest recently, with triplet–triplet annihilation
driven photon upconversion (TTA-UC) gaining widespread recognition
due to its ability to function under low-intensity, noncoherent light.
Herein, four diphenylanthracene (DPA) dimers are investigated to explore
how the structure of these dimers affects upconversion efficiency.
Also, the mechanism responsible for intramolecular upconversion is
elucidated. In particular, two models are compared using steady-state
and time-resolved simulations of the TTA-UC emission intensities and
kinetics. All dimers perform TTA-UC efficiently in the presence of
the sensitizer platinum octaethylporphyrin. The meta-coupled dimer
1,3-DPA2 performs best yielding a 21.2% upconversion quantum
yield (out of a 50% maximum), which is close to that of the reference
monomer DPA (24.0%). Its superior performance compared to the other
dimers is primarily ascribed to the longer triplet lifetime of this
dimer (4.7 ms), thus reinforcing the importance of this parameter.
Comparisons between simulations and experiments reveal that the double-sensitization
mechanism is part of the mechanism of intramolecular upconversion
and that this additional pathway could be of great significance under
specific conditions. The results from this study can thus act as a
guide not only in terms of annihilator design but also for the design
of future solid-state systems where intramolecular exciton migration
is anticipated to play a major role.
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Affiliation(s)
- Axel Olesund
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Victor Gray
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden.,Department of Chemistry, Ångström Laboratory, Uppsala University, Box 532, 751 20 Uppsala, Sweden
| | - Jerker Mårtensson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Bo Albinsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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7
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Congrave DG, Drummond BH, Gray V, Bond AD, Rao A, Friend RH, Bronstein H. Suppressing aggregation induced quenching in anthracene based conjugated polymers. Polym Chem 2021. [DOI: 10.1039/d1py00118c] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We demonstrate an anthracene based conjugated polymer with a solid state PLQY that is effectively unchanged compared to solution measurements, alongside an identical PL 0–0 transition wavelength in solution and thin film.
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Affiliation(s)
| | | | - Victor Gray
- Cavendish Laboratory
- University of Cambridge
- Cambridge
- UK
- Department of Chemistry – Ångström Laboratory
| | - Andrew D. Bond
- Department of Chemistry
- University of Cambridge
- Cambridge
- UK
| | - Akshay Rao
- Cavendish Laboratory
- University of Cambridge
- Cambridge
- UK
| | | | - Hugo Bronstein
- Department of Chemistry
- University of Cambridge
- Cambridge
- UK
- Cavendish Laboratory
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8
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Barbosa de Mattos DF, Dreos A, Johnstone MD, Runemark A, Sauvée C, Gray V, Moth-Poulsen K, Sundén H, Abrahamsson M. Covalent incorporation of diphenylanthracene in oxotriphenylhexanoate organogels as a quasi-solid photon upconversion matrix. J Chem Phys 2020; 153:214705. [PMID: 33291902 DOI: 10.1063/5.0029307] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Triplet-triplet annihilation photon upconversion (TTA-UC) in solid state assemblies are desirable since they can be easily incorporated into devices such as solar cells, thus utilizing more of the solar spectrum. Realizing this is, however, a significant challenge that must circumvent the need for molecular diffusion, poor exciton migration, and detrimental back energy transfer among other hurdles. Here, we show that the above-mentioned issues can be overcome using the versatile and easily synthesized oxotriphenylhexanoate (OTHO) gelator that allows covalent incorporation of chromophores (or other functional units) at well-defined positions. To study the self-assembly properties as well as its use as a TTA-UC platform, we combine the benchmark couple platinum octaethylporphyrin as a sensitizer and 9,10-diphenylanthracene (DPA) as an annihilator, where DPA is covalently linked to the OTHO gelator at different positions. We show that TTA-UC can be achieved in the chromophore-decorated gels and that the position of attachment affects the photophysical properties as well as triplet energy transfer and triplet-triplet annihilation. This study not only provides proof-of-principle for the covalent approach but also highlights the need for a detailed mechanistic insight into the photophysical processes underpinning solid state TTA-UC.
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Affiliation(s)
- Deise F Barbosa de Mattos
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Ambra Dreos
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Mark D Johnstone
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - August Runemark
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Claire Sauvée
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Victor Gray
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Kasper Moth-Poulsen
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Henrik Sundén
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Maria Abrahamsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, Sweden
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9
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Huang Z, Xu Z, Huang T, Gray V, Moth-Poulsen K, Lian T, Tang ML. Evolution from Tunneling to Hopping Mediated Triplet Energy Transfer from Quantum Dots to Molecules. J Am Chem Soc 2020; 142:17581-17588. [DOI: 10.1021/jacs.0c07727] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Zhiyuan Huang
- Department of Chemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Zihao Xu
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Tingting Huang
- Department of Chemistry, University of California, Riverside, Riverside, California 92521, United States
| | - Victor Gray
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
- Department of Chemistry − Ångström Laboratory, Uppsala University, Box
523, 751 20 Uppsala, Sweden
| | - Kasper Moth-Poulsen
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Tianquan Lian
- Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States
| | - Ming Lee Tang
- Department of Chemistry, University of California, Riverside, Riverside, California 92521, United States
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10
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Gray V, Zhang Z, Dowland S, Allardice JR, Alvertis AM, Xiao J, Greenham NC, Anthony JE, Rao A. Thiol-Anchored TIPS-Tetracene Ligands with Quantitative Triplet Energy Transfer to PbS Quantum Dots and Improved Thermal Stability. J Phys Chem Lett 2020; 11:7239-7244. [PMID: 32787302 DOI: 10.1021/acs.jpclett.0c02031] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Triplet energy transfer between inorganic quantum dots (QDs) and organic materials plays a fundamental role in many optoelectronic applications based on these nanocomposites. Attaching organic molecules to the QD as transmitter ligands has been shown to facilitate transfer both to and from QDs. Here we show that the often disregarded thiol anchoring group can achieve quantitative triplet energy transfer yields in a PbS QD system with 6,11-bis[(triisopropylsilyl)ethynyl]tetracene-2-methylthiol (TET-SH) ligands. We demonstrate efficient triplet transfer in a singlet fission-based photon multiplication system with 5,12-bis[(triisopropylsilyl)ethynyl]tetracene generating triplets in solution that transfer to the PbS QDs via the thiol ligand TET-SH. Importantly, we demonstrate the increased thermal stability of the PbS/TET-SH system, compared to the traditional carboxylic acid counterpart, allowing for higher photoluminescence quantum yields.
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Affiliation(s)
- Victor Gray
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
- Ångström Laboratory, Department of Chemistry, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | - Zhilong Zhang
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Simon Dowland
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Jesse R Allardice
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Antonios M Alvertis
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - James Xiao
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - Neil C Greenham
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
| | - John E Anthony
- University of Kentucky Center for Applied Energy Research, 2582 Research Park Drive, Lexington, Kentucky 40511, United States
| | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, U.K
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11
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Gray V, Allardice JR, Zhang Z, Dowland S, Xiao J, Petty A, Anthony JE, Greenham NC, Rao A. Correction to Direct vs Delayed Triplet Energy Transfer from Organic Semiconductors to Quantum Dots and Implications for Luminescent Harvesting of Triplet Excitons. ACS Nano 2020; 14:10748-10749. [PMID: 32806041 PMCID: PMC7853634 DOI: 10.1021/acsnano.0c06432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Indexed: 06/11/2023]
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12
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Sakakibara N, Clavijo P, George A, Gray V, King K, Ponnamperuma R, Van Waes C, Allen C, Weinberg W. 111 Defining the immune tumor microenvironment in a genetic mouse model of multistep squamous cell carcinogenesis. J Invest Dermatol 2020. [DOI: 10.1016/j.jid.2020.03.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Gray V, Allardice JR, Zhang Z, Dowland S, Xiao J, Petty AJ, Anthony JE, Greenham NC, Rao A. Direct vs Delayed Triplet Energy Transfer from Organic Semiconductors to Quantum Dots and Implications for Luminescent Harvesting of Triplet Excitons. ACS Nano 2020; 14:4224-4234. [PMID: 32181633 PMCID: PMC7199217 DOI: 10.1021/acsnano.9b09339] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 03/17/2020] [Indexed: 05/31/2023]
Abstract
Hybrid inorganic-organic materials such as quantum dots (QDs) coupled with organic semiconductors have a wide range of optoelectronic applications, taking advantage of the respective materials' strengths. A key area of investigation in such systems is the transfer of triplet exciton states to and from QDs, which has potential applications in the luminescent harvesting of triplet excitons generated by singlet fission, in photocatalysis and photochemical upconversion. While the transfer of energy from QDs to the triplet state of organic semiconductors has been intensely studied in recent years, the mechanism and materials parameters controlling the reverse process, triplet transfer to QDs, have not been well investigated. Here, through a combination of steady-state and time-resolved optical spectroscopy we study the mechanism and energetic dependence of triplet energy transfer from an organic ligand (TIPS-tetracene carboxylic acid) to PbS QDs. Over an energetic range spanning from exothermic (-0.3 eV) to endothermic (+0.1 eV) triplet energy transfer we find that the triplet energy transfer to the QD occurs through a single step process with a clear energy dependence that is consistent with an electron exchange mechanism as described by Marcus-Hush theory. In contrast, the reverse process, energy transfer from the QD to the triplet state of the ligand, does not show any energy dependence in the studied energy range; interestingly, a delayed formation of the triplet state occurs relative to the quantum dots' decay. Based on the energetic dependence of triplet energy transfer we also suggest design criteria for future materials systems where triplet excitons from organic semiconductors are harvested via QDs, for instance in light emitting structures or the harvesting of triplet excitons generated via singlet fission.
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Affiliation(s)
- Victor Gray
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
- Department
of Chemistry—Ångström Laboratory, Uppsala University, Box 523, 751 20 Uppsala, Sweden
| | - Jesse R. Allardice
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Zhilong Zhang
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Simon Dowland
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - James Xiao
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Anthony J. Petty
- Department
of Chemistry, University of Kentucky, 161 Jacobs Science Building, Lexington, Kentucky 40506-0174, United States
| | - John E. Anthony
- Department
of Chemistry, University of Kentucky, 161 Jacobs Science Building, Lexington, Kentucky 40506-0174, United States
| | - Neil C. Greenham
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Akshay Rao
- Cavendish
Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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14
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Ye C, Gray V, Kushwaha K, Kumar Singh S, Erhart P, Börjesson K. Optimizing photon upconversion by decoupling excimer formation and triplet triplet annihilation. Phys Chem Chem Phys 2020; 22:1715-1720. [PMID: 31895392 DOI: 10.1039/c9cp06561j] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Perylene is a promising annihilator candidate for triplet-triplet annihilation photon upconversion, which has been successfully used in solar cells and in photocatalysis. Perylene can, however, form excimers, reducing the energy conversion efficiency and hindering further development of TTA-UC systems. Alkyl substitution of perylene can suppress excimer formation, but decelerate triplet energy transfer and triplet-triplet annihilation at the same time. Our results show that mono-substitution with small alkyl groups selectively blocks excimer formation without severly compromising the TTA-UC efficiency. The experimental results are complemented by DFT calculations, which demonstrate that excimer formation is suppressed by steric repulsion. The results demonstrate how the chemical structure can be modified to block unwanted intermolecular excited state relaxation pathways with minimal effect on the preferred ones.
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Affiliation(s)
- Chen Ye
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg, Sweden.
| | - Victor Gray
- Department of Chemistry-Ångström Laboratory, Uppsala University, 75120, Uppsala, Sweden and Department of Physics, Cavendish Laboratory, University of Cambridge, 19 JJ Thompson Avenue, Cambridge, CB3 0HE, UK
| | - Khushbu Kushwaha
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg, Sweden.
| | - Sandeep Kumar Singh
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Paul Erhart
- Department of Physics, Chalmers University of Technology, 41296 Gothenburg, Sweden
| | - Karl Börjesson
- Department of Chemistry and Molecular Biology, University of Gothenburg, 41296 Gothenburg, Sweden.
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15
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Edhborg F, Küçüköz B, Gray V, Albinsson B. Singlet Energy Transfer in Anthracene-Porphyrin Complexes: Mechanism, Geometry, and Implications for Intramolecular Photon Upconversion. J Phys Chem B 2019; 123:9934-9943. [PMID: 31647236 DOI: 10.1021/acs.jpcb.9b07991] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this work we show that the mechanism for singlet excitation energy transfer (SET) in coordination complexes changes upon changing a single atom. SET is governed by two different mechanisms; Förster resonance energy transfer (FRET) based on Coulombic, through-space interactions, or Dexter energy transfer relying on exchange, through-bond interactions. On the basis of time-resolved fluorescence and transient absorption measurements, we conduct a mechanistic study of SET from a set of photoexcited anthracene donors to axially coordinated porphyrin acceptors, revealing the effect of coordination geometry and a very profound effect of the porphyrin central metal atom. We found that FRET is the dominating mechanism of SET for complexes with zinc-octaethylporphyrin (ZnOEP) as the acceptor, while Dexter energy transfer is the dominating mechanism of SET in a corresponding ruthenium complex (RuOEP). In addition, by analyzing the coordination geometry of the complexes and its temperature dependence, the binding angle potential energy of axially coordinated porphyrin complexes could be estimated. The results of this study are of fundamental importance and are discussed with respect to the consequences for developing intramolecular triplet-triplet annihilation photon upconversion in coordination complexes.
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Affiliation(s)
- Fredrik Edhborg
- Department of Chemistry and Chemical Engineering , Chalmers University of Technology , Gothenburg , Sweden
| | - Betül Küçüköz
- Department of Chemistry and Chemical Engineering , Chalmers University of Technology , Gothenburg , Sweden
| | - Victor Gray
- Department of Chemistry and Chemical Engineering , Chalmers University of Technology , Gothenburg , Sweden
| | - Bo Albinsson
- Department of Chemistry and Chemical Engineering , Chalmers University of Technology , Gothenburg , Sweden
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16
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Allardice JR, Thampi A, Dowland S, Xiao J, Gray V, Zhang Z, Budden P, Petty AJ, Davis NJLK, Greenham NC, Anthony JE, Rao A. Correction to “Engineering Molecular Ligand Shells on Quantum Dots for Quantitative Harvesting of Triplet Excitons Generated by Singlet Fission”. J Am Chem Soc 2019; 141:17949. [PMID: 31651167 PMCID: PMC8154535 DOI: 10.1021/jacs.9b10981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Weir MP, Toolan DTW, Kilbride RC, Penfold NJW, Washington AL, King SM, Xiao J, Zhang Z, Gray V, Dowland S, Winkel J, Greenham NC, Friend RH, Rao A, Ryan AJ, Jones RAL. Ligand Shell Structure in Lead Sulfide-Oleic Acid Colloidal Quantum Dots Revealed by Small-Angle Scattering. J Phys Chem Lett 2019; 10:4713-4719. [PMID: 31362504 PMCID: PMC7007257 DOI: 10.1021/acs.jpclett.9b01008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 07/30/2019] [Indexed: 05/18/2023]
Abstract
Nanocrystal quantum dots are generally coated with an organic ligand layer. These layers are a necessary consequence of their chemical synthesis, and in addition they play a key role in controlling the optical and electronic properties of the system. Here we describe a method for quantitative measurement of the ligand layer in 3 nm diameter lead sulfide-oleic acid quantum dots. Complementary small-angle X-ray and neutron scattering (SAXS and SANS) studies give a complete and quantitative picture of the nanoparticle structure. We find greater-than-monolayer coverage of oleic acid and a significant proportion of ligand remaining in solution, and we demonstrate reversible thermal cycling of the oleic acid coverage. We outline the effectiveness of simple purification procedures with applications in preparing dots for efficient ligand exchange. Our method is transferrable to a wide range of colloidal nanocrystals and ligand chemistries, providing the quantitative means to enable the rational design of ligand-exchange procedures.
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Affiliation(s)
- Michael P. Weir
- Department
of Physics and Astronomy, The University
of Sheffield, Sheffield S3 7RH, United Kingdom
- E-mail:
| | - Daniel T. W. Toolan
- Department
of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Rachel C. Kilbride
- Department
of Physics and Astronomy, The University
of Sheffield, Sheffield S3 7RH, United Kingdom
| | | | - Adam L. Washington
- ISIS
Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United
Kingdom
| | - Stephen M. King
- ISIS
Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United
Kingdom
| | - James Xiao
- Cavendish
Laboratory, Cambridge University, Cambridge CB3 0HE, United Kingdom
| | - Zhilong Zhang
- Cavendish
Laboratory, Cambridge University, Cambridge CB3 0HE, United Kingdom
| | - Victor Gray
- Cavendish
Laboratory, Cambridge University, Cambridge CB3 0HE, United Kingdom
| | - Simon Dowland
- Cavendish
Laboratory, Cambridge University, Cambridge CB3 0HE, United Kingdom
| | - Jurjen Winkel
- Cavendish
Laboratory, Cambridge University, Cambridge CB3 0HE, United Kingdom
| | - Neil C. Greenham
- Cavendish
Laboratory, Cambridge University, Cambridge CB3 0HE, United Kingdom
| | - Richard H. Friend
- Cavendish
Laboratory, Cambridge University, Cambridge CB3 0HE, United Kingdom
| | - Akshay Rao
- Cavendish
Laboratory, Cambridge University, Cambridge CB3 0HE, United Kingdom
| | - Anthony J. Ryan
- Department
of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Richard A. L. Jones
- Department
of Physics and Astronomy, The University
of Sheffield, Sheffield S3 7RH, United Kingdom
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18
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Allardice JR, Thampi A, Dowland S, Xiao J, Gray V, Zhang Z, Budden P, Petty AJ, Davis NJLK, Greenham NC, Anthony JE, Rao A. Engineering Molecular Ligand Shells on Quantum Dots for Quantitative Harvesting of Triplet Excitons Generated by Singlet Fission. J Am Chem Soc 2019; 141:12907-12915. [PMID: 31336046 PMCID: PMC7007228 DOI: 10.1021/jacs.9b06584] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
![]()
Singlet
fission is an exciton multiplication process in organic
molecules in which a photogenerated spin-singlet exciton is rapidly
and efficiently converted to two spin-triplet excitons. This process
offers a mechanism to break the Shockley–Queisser limit by
overcoming the thermalization losses inherent to all single-junction
photovoltaics. One of the most promising methods to harness the singlet
fission process is via the efficient extraction of the dark triplet
excitons into quantum dots (QDs) where they can recombine radiatively,
thereby converting high-energy photons to pairs of low-energy photons,
which can then be captured in traditional inorganic PVs such as Si.
Such a singlet fission photon multiplication (SF-PM) process could
increase the efficiency of the best Si cells from 26.7% to 32.5%,
breaking the Shockley–Queisser limit. However, there has been
no demonstration of such a singlet fission photon multiplication (SF-PM)
process in a bulk system to date. Here, we demonstrate a solution-based
bulk SF-PM system based on the singlet fission material TIPS-Tc combined
with PbS QDs. Using a range of steady-state and time-resolved measurements
combined with analytical modeling we study the dynamics and mechanism
of the triplet harvesting process. We show that the system absorbs
>95% of incident photons within the singlet fission material to
form
singlet excitons, which then undergo efficient singlet fission in
the solution phase (135 ± 5%) before quantitative harvesting
of the triplet excitons (95 ± 5%) via a low concentration of
QD acceptors, followed by the emission of IR photons. We find that
in order to achieve efficient triplet harvesting it is critical to
engineer the surface of the QD with a triplet transfer ligand and
that bimolecular decay of triplets is potentially a major loss pathway
which can be controlled via tuning the concentration of QD acceptors.
We demonstrate that the photon multiplication efficiency is maintained
up to solar fluence. Our results establish the solution-based SF-PM
system as a simple and highly tunable platform to understand the dynamics
of a triplet energy transfer process between organic semiconductors
and QDs, one that can provide clear design rules for new materials.
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Affiliation(s)
- Jesse R Allardice
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Arya Thampi
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Simon Dowland
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - James Xiao
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Victor Gray
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom.,Department of Chemistry, Ångström Laboratory , Uppsala University , Box 532, Uppsala SE-751 20 , Sweden
| | - Zhilong Zhang
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Peter Budden
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - Anthony J Petty
- Center for Applied Energy Research , University of Kentucky , Research Park Drive , Lexington , Kentucky 40511 , United States
| | - Nathaniel J L K Davis
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom.,The MacDiarmid Institute for Advanced Materials and Nanotechnology, The Dodd-Walls Centre for Photonic and Quantum Technologies, School of Chemical and Physical Sciences , Victoria University of Wellington , Wellington 6140 , New Zealand
| | - Neil C Greenham
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
| | - John E Anthony
- Center for Applied Energy Research , University of Kentucky , Research Park Drive , Lexington , Kentucky 40511 , United States
| | - Akshay Rao
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , United Kingdom
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19
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Ye C, Gray V, Mårtensson J, Börjesson K. Annihilation Versus Excimer Formation by the Triplet Pair in Triplet-Triplet Annihilation Photon Upconversion. J Am Chem Soc 2019; 141:9578-9584. [PMID: 31131601 PMCID: PMC6608582 DOI: 10.1021/jacs.9b02302] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The triplet pair is the key functional unit in triplet-triplet annihilation photon upconversion. The same molecular properties that stabilize the triplet pair also allow dimers to form on the singlet energy surface, creating an unwanted energy relaxation pathway. Here we show that excimer formation most likely is a consequence of a triplet dimer formed before the annihilation event. Polarity-dependent studies were performed to elucidate how to promote wanted emission pathways over excimer formation. Furthermore, we show that the yield of triplet-triplet annihilation is increased in higher-viscosity solvents. The results will bring new insights in how to increase the upconversion efficiency and how to avoid energy-loss channels.
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Affiliation(s)
- Chen Ye
- Department of Chemistry and Molecular Biology , University of Gothenburg , Kemigården 4 , Gothenburg , Sweden
| | - Victor Gray
- Department of Chemical and Biological Engineering/Organic Chemistry , Chalmers University of Technology , SE-412 96 Gothenburg , Sweden.,Department of Chemistry-Ångström Laboratory , Uppsala University , Box 523, 751 20 Uppsala , Sweden.,Department of Physics, Cavendish Laboratory , University of Cambridge , 19 JJ Thompson Avenue , Cambridge CB3 0HE , U.K
| | - Jerker Mårtensson
- Department of Chemical and Biological Engineering/Organic Chemistry , Chalmers University of Technology , SE-412 96 Gothenburg , Sweden
| | - Karl Börjesson
- Department of Chemistry and Molecular Biology , University of Gothenburg , Kemigården 4 , Gothenburg , Sweden
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20
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Nishimura N, Allardice JR, Xiao J, Gu Q, Gray V, Rao A. Photon upconversion utilizing energy beyond the band gap of crystalline silicon with a hybrid TES-ADT/PbS quantum dots system. Chem Sci 2019; 10:4750-4760. [PMID: 31160951 PMCID: PMC6510314 DOI: 10.1039/c9sc00821g] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 03/22/2019] [Indexed: 12/18/2022] Open
Abstract
The recent introduction of inorganic semiconductor quantum dots (QDs) as triplet sensitizers for molecular semiconductors has led to significant interest in harvesting low energy photons, which can then be used for photon upconversion (PUC), via triplet-triplet annihilation (TTA). A key goal is the harvesting of photons from below the bandgap of crystalline silicon 1.12 eV (≈1100 nm) and their upconversion into the visible region. In practice, the systems demonstrated so far have been limited to harvesting photons with energies above 1.2 eV (≈1 μm), due to two reasons: firstly the need to use transmitter ligands which allow efficient energy harvesting from the QD but introduce an energy loss of larger than 200 meV in transmission from the QD to the annihilator, and secondly due to the use of molecules such as tetracene which cannot accept smaller energy than 1.2 eV. Here, we introduce a new strategy to overcome these difficulties by using a low energy triplet annihilator that also harvests excitations efficiently from QDs. Specifically, we show that 5,11-bis(triethylsilylethynyl)anthradithiophene (TES-ADT, triplet energy of 1.08 eV: ca. 1150 nm) functions as a triplet annihilator (20% TTA efficiency) while also rapidly extracting triplet excitons from lead sulfide (PbS) QDs with a rate constant of k = ca. 2 × 10-8 s-1 with an excitation at 1064 nm. This rate is consistent with an orbital overlap between TES-ADT and PbS QDs, which we propose is due to the thiophene group of TES-ADT, which enables a close association with the PbS surface, allowing this system to function both as annihilator and transmitter. Our results pave the way for the design of triplet annihilators that can closely associate with the QD surface and harvest low energy excitons with minute losses in energy during the TET process, with the ultimate goal of efficiently utilizing photon energy beyond the bandgap of crystalline silicon.
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Affiliation(s)
- Naoyuki Nishimura
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge , CB3 0HE , UK . .,Corporate Research & Development , Asahi-Kasei Corporation , 2-1 Samejima, Fuji , Shizuoka , 416-8501 , Japan
| | - Jesse R Allardice
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge , CB3 0HE , UK .
| | - James Xiao
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge , CB3 0HE , UK .
| | - Qifei Gu
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge , CB3 0HE , UK .
| | - Victor Gray
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge , CB3 0HE , UK . .,Department of Chemistry , Ångström Laboratory , Uppsala University , Box 532 , SE-751 20 Uppsala , Sweden
| | - Akshay Rao
- Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge , CB3 0HE , UK .
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21
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Chiong R, Gray V. Qualitative Findings of a Nutrition Education Intervention Pilot. J Acad Nutr Diet 2018. [DOI: 10.1016/j.jand.2018.06.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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22
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Goh V, Petersen S, Gray V, Barrack M, Wiss D, Wang L. Eating Disorder Risk Evaluation for Males in Substance Abuse Recovery. J Acad Nutr Diet 2018. [DOI: 10.1016/j.jand.2018.06.285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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23
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Goh V, La Rose M, Gray V, Wang L, Hill M. The Relationship Between Dietary Fat and Cognitive Status in Older Adults. J Acad Nutr Diet 2018. [DOI: 10.1016/j.jand.2018.06.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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24
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Lin S, Gray V, Galvan C, Ede A, Rodriguez A. Impacts of a Nutrition and Fitness Intervention on Adolescent Girls in a Leadership Academy. J Acad Nutr Diet 2018. [DOI: 10.1016/j.jand.2018.06.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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25
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Gray V, Küçüköz B, Edhborg F, Abrahamsson M, Moth-Poulsen K, Albinsson B. Singlet and triplet energy transfer dynamics in self-assembled axial porphyrin–anthracene complexes: towards supra-molecular structures for photon upconversion. Phys Chem Chem Phys 2018; 20:7549-7558. [DOI: 10.1039/c8cp00884a] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Singlet and triplet energy transfer dynamics in anthracene–ruthenium porphyrin complexes, and their application to photon upconversion.
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Affiliation(s)
- Victor Gray
- Chalmers University of Technology, Department of Chemistry and Chemical Engineering
- Gothenburg
- Sweden
| | - Betül Küçüköz
- Chalmers University of Technology, Department of Chemistry and Chemical Engineering
- Gothenburg
- Sweden
| | - Fredrik Edhborg
- Chalmers University of Technology, Department of Chemistry and Chemical Engineering
- Gothenburg
- Sweden
| | - Maria Abrahamsson
- Chalmers University of Technology, Department of Chemistry and Chemical Engineering
- Gothenburg
- Sweden
| | - Kasper Moth-Poulsen
- Chalmers University of Technology, Department of Chemistry and Chemical Engineering
- Gothenburg
- Sweden
| | - Bo Albinsson
- Chalmers University of Technology, Department of Chemistry and Chemical Engineering
- Gothenburg
- Sweden
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26
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Osterman S, Barrack M, Gray V. A Qualitative and Quantitative Evaluation of Dietary Supplement Topics Prioritized by Collegiate Athletes. J Acad Nutr Diet 2017. [DOI: 10.1016/j.jand.2017.06.338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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27
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Lin S, Rafferty A, Nguyen J, Gray V, Nguyen-Rodriguez S, Barrack M. Parental Perceptions of Snacking Environments in Youth Sports. J Acad Nutr Diet 2017. [DOI: 10.1016/j.jand.2017.06.269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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28
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29
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Minkow S, Gray V, Reiboldt W, Gonitzke D. Cooking Attitudes, Behaviors, and Self-Efficacy in Relation to Fruit and Vegetable Intake Among Young Adults. J Acad Nutr Diet 2017. [DOI: 10.1016/j.jand.2017.06.232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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30
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Gray V, Xia P, Huang Z, Moses E, Fast A, Fishman DA, Vullev VI, Abrahamsson M, Moth-Poulsen K, Lee Tang M. CdS/ZnS core-shell nanocrystal photosensitizers for visible to UV upconversion. Chem Sci 2017; 8:5488-5496. [PMID: 28970929 PMCID: PMC5613741 DOI: 10.1039/c7sc01610g] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 05/30/2017] [Indexed: 12/29/2022] Open
Abstract
Herein we report the first example of nanocrystal (NC) sensitized triplet-triplet annihilation based photon upconversion from the visible to ultraviolet (vis-to-UV). Many photocatalyzed reactions, such as water splitting, require UV photons in order to function efficiently. Upconversion is one possible means of extending the usable range of photons into the visible. Vis-to-UV upconversion is achieved with CdS/ZnS core-shell NCs as the sensitizer and 2,5-diphenyloxazole (PPO) as annihilator and emitter. The ZnS shell was crucial in order to achieve any appreciable upconversion. From time resolved photoluminescence and transient absorption measurements we conclude that the ZnS shell affects the NC and triplet energy transfer (TET) from NC to PPO in two distinct ways. Upon ZnS growth the surface traps are passivated thus increasing the TET. The shell, however, also acts as a tunneling barrier for TET, reducing the efficiency. This leads to an optimal shell thickness where the upconversion quantum yield (Φ'UC) is maximized. Here the maximum Φ'UC was determined to be 5.2 ± 0.5% for 4 monolayers of ZnS shell on CdS NCs.
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Affiliation(s)
- Victor Gray
- Department of Chemistry and Chemical Engineering , Chalmers University of Technology , 412 96 Gothenburg , Sweden
| | - Pan Xia
- Materials Science & Engineering Program , University of California, Riverside , 900 University Ave. , Riverside , CA 92521 , USA
| | - Zhiyuan Huang
- Department of Chemistry , University of California, Riverside , 900 University Ave. , Riverside , CA 92521 , USA .
| | - Emily Moses
- Department of Chemistry , University of California, Riverside , 900 University Ave. , Riverside , CA 92521 , USA .
| | - Alexander Fast
- Department of Chemistry , University of California , Irvine , CA 92697 , USA
| | - Dmitry A Fishman
- Department of Chemistry , University of California , Irvine , CA 92697 , USA
| | - Valentine I Vullev
- Department of Chemistry , University of California, Riverside , 900 University Ave. , Riverside , CA 92521 , USA .
| | - Maria Abrahamsson
- Department of Chemistry and Chemical Engineering , Chalmers University of Technology , 412 96 Gothenburg , Sweden
| | - Kasper Moth-Poulsen
- Department of Chemistry and Chemical Engineering , Chalmers University of Technology , 412 96 Gothenburg , Sweden
| | - Ming Lee Tang
- Department of Chemistry , University of California, Riverside , 900 University Ave. , Riverside , CA 92521 , USA .
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Gray V, Dreos A, Erhart P, Albinsson B, Moth-Poulsen K, Abrahamsson M. Loss channels in triplet–triplet annihilation photon upconversion: importance of annihilator singlet and triplet surface shapes. Phys Chem Chem Phys 2017; 19:10931-10939. [DOI: 10.1039/c7cp01368j] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Differences in triplet–triplet annihilation photon upconversion efficiencies between structurally similar annihilators can be understood in terms of singlet and triplet surface shapes.
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Affiliation(s)
- Victor Gray
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
| | - Ambra Dreos
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
| | - Paul Erhart
- Department of Physics
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
| | - Bo Albinsson
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
| | - Kasper Moth-Poulsen
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
| | - Maria Abrahamsson
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- 412 96 Gothenburg
- Sweden
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Iro MA, Sadarangani M, Absoud M, Chong WK, Clark CA, Easton A, Gray V, Kneen R, Lim M, Pike M, Solomon T, Vincent A, Willis L, Yu LM, Pollard AJ. ImmunoglobuliN in the Treatment of Encephalitis (IgNiTE): protocol for a multicentre randomised controlled trial. BMJ Open 2016; 6:e012356. [PMID: 27810972 PMCID: PMC5129051 DOI: 10.1136/bmjopen-2016-012356] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
INTRODUCTION Infectious and immune-mediated encephalitides are important but under-recognised causes of morbidity and mortality in childhood, with a 7% death rate and up to 50% morbidity after prolonged follow-up. There is a theoretical basis for ameliorating the immune response with intravenous immunoglobulin (IVIG), which is supported by empirical evidence of a beneficial response following its use in the treatment of viral and autoimmune encephalitis. In immune-mediated encephalitis, IVIG is often used after a delay (by weeks in some cases), while diagnosis is confirmed. Wider use of IVIG in infectious encephalitis and earlier use in immune-mediated encephalitis could improve outcomes for these conditions. We describe the protocol for the first ever randomised control trial of IVIG treatment for children with all-cause encephalitis. METHODS AND ANALYSIS 308 children (6 months to 16 years) with a diagnosis of acute/subacute encephalitis will be recruited in ∼30 UK hospitals and randomised to receive 2 doses (1 g/kg/dose) of either IVIG or matching placebo, in addition to standard treatment. Recruitment will be over a 42-month period and follow-up of each participant will be for 12 months post randomisation. The primary outcome is 'good recovery' (score of 2 or lower on the Glasgow Outcome Score Extended-paediatric version), at 12 months after randomisation. Additional secondary neurological measures will be collected at 4-6 weeks after discharge from acute care and at 6 and 12 months after randomisation. Safety, radiological, other autoimmune and tertiary outcomes will also be assessed. ETHICS AND DISSEMINATION This trial has been approved by the UK National Research Ethics committee (South Central-Oxford A; REC 14/SC/1416). Current protocol: V4.0 (10/03/2016). The findings will be presented at national and international meetings and conferences and published in peer-reviewed journals. TRIAL REGISTRATION NUMBERS NCT02308982, EudraCT201400299735 and ISRCTN15791925; Pre-results.
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Affiliation(s)
- M A Iro
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and NIHR Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - M Sadarangani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and NIHR Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Department of Paediatrics, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Vaccine Evaluation Center, BC Children's Hospital Research Institute, University of British Columbia, Vancouver BC, Canada
| | - M Absoud
- Department of Children's Neurosciences, Evelina London Children's Hospital at Guy's and St Thomas’ NHS Foundation Trust, King's Health Partners Academic Health Science Centre, London, UK
| | - W K Chong
- Department of Radiology, Great Ormond Street Hospital for Children, London, UK
| | - C A Clark
- Institute of Child Health, University College London, London, UK
| | - A Easton
- The Encephalitis Society, Malton, North Yorkshire, UK
| | - V Gray
- Psychological services (Paediatrics), Alder Hey Children's NHS Foundation Trust, Liverpool, UK
| | - R Kneen
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
- Littlewoods Neuroscience Foundation, Department of Neurology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK
| | - M Lim
- Department of Children's Neurosciences, Evelina London Children's Hospital at Guy's and St Thomas’ NHS Foundation Trust, King's Health Partners Academic Health Science Centre, London, UK
| | - M Pike
- Department of Paediatric Neurology, Oxford University Hospitals NHS Trust, Oxford, UK
| | - T Solomon
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
- National Institute for Health Research Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool, UK
- Walton Centre NHS Foundation Trust, Liverpool, UK
| | - A Vincent
- Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - L Willis
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and NIHR Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - L-M Yu
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
| | - A J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and NIHR Biomedical Research Centre, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Department of Paediatrics, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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Abstract
Photon upconversion has the potential to increase the efficiency of single bandgap solar cells beyond the Shockley Queisser limit. Efficient light management is an important point in this context. Here we demonstrate that the direction of upconverted emission can be controlled in a reversible way, by embedding anthracene derivatives together with palladium porphyrin in a liquid crystalline matrix. The system is employed in a triplet-triplet annihilation photon upconversion scheme demonstrating controlled switching of directional anti Stokes emission. Using this approach an emission ratio of 0.37 between the axial and longitudinal emission directions and a directivity of 1.52 is achieved, reasonably close to the theoretical maximal value of 2 obtained from a perfectly oriented sample. The system can be switched for multiple cycles without any visible degradation and the speed of switching is only limited by the intrinsic rate of alignment of the liquid crystalline matrix. Photon upconversion can be used to harvest low energy photons, which are otherwise lost in solar cells. Here, Börjesson et al. use a well-oriented liquid crystal matrix to host the upconversion system in order to emit upconverted photons in a preferential direction, where the solar cells would be located.
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Affiliation(s)
- K Börjesson
- Department of Chemistry and Molecular Biology, University of Gothenburg, Kemigården 4, 412 96 Gothenburg, Sweden.,Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - P Rudquist
- Department of Microtechnology and Nanoscience, MC2, Chalmers University of Technology, Kemivägen 9, 412 96 Gothenburg, Sweden
| | - V Gray
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - K Moth-Poulsen
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
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Lennartson A, Lundin A, Börjesson K, Gray V, Moth-Poulsen K. Tuning the photochemical properties of the fulvalene-tetracarbonyl-diruthenium system. Dalton Trans 2016; 45:8740-4. [DOI: 10.1039/c6dt01343k] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In a Molecular Solar–Thermal Energy Storage (MOST) system, solar energy is converted to chemical energy using a compound that undergoes reversible endothermic photoisomerization.
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Affiliation(s)
- Anders Lennartson
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- SE-412 96 Gothenburg
- Sweden
| | - Angelica Lundin
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- SE-412 96 Gothenburg
- Sweden
| | - Karl Börjesson
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- SE-412 96 Gothenburg
- Sweden
- Present address: Department of Chemistry and Molecular Biology
| | - Victor Gray
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- SE-412 96 Gothenburg
- Sweden
| | - Kasper Moth-Poulsen
- Department of Chemistry and Chemical Engineering
- Chalmers University of Technology
- SE-412 96 Gothenburg
- Sweden
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Gray V, Barrack M, Sauceda A, Singh-Carlson S. Parent Perceptions of Healthy Snack Guidelines Implemented in a Southern California Youth Soccer Organization. J Acad Nutr Diet 2015. [DOI: 10.1016/j.jand.2015.06.293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Börjesson K, Ćoso D, Gray V, Grossman JC, Guan J, Harris CB, Hertkorn N, Hou Z, Kanai Y, Lee D, Lomont JP, Majumdar A, Meier SK, Moth-Poulsen K, Myrabo RL, Nguyen SC, Segalman RA, Srinivasan V, Tolman WB, Vinokurov N, Vollhardt KPC, Weidman TW. Exploring the Potential of Fulvalene Dimetals as Platforms for Molecular Solar Thermal Energy Storage: Computations, Syntheses, Structures, Kinetics, and Catalysis. Chemistry 2014; 20:15587-604. [DOI: 10.1002/chem.201404170] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Indexed: 11/11/2022]
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Gray V. Incorporation of Globally-Focused Public Health Readings into an Advanced Community Nutrition Course: Impact on Student Understanding and Engagement. J Acad Nutr Diet 2014. [DOI: 10.1016/j.jand.2014.06.233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Skwierczynski R, Curry P, Gray V, Krämer J, Stippler E, Suggett J, Mirza T, Brown W. Revision of the Dissolution Procedure: Development and Validation <1092>. DISSOLUT TECHNOL 2014. [DOI: 10.14227/dt210114p6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Gray V, Dzebo D, Abrahamsson M, Albinsson B, Moth-Poulsen K. Triplet–triplet annihilation photon-upconversion: towards solar energy applications. Phys Chem Chem Phys 2014; 16:10345-52. [DOI: 10.1039/c4cp00744a] [Citation(s) in RCA: 233] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This perspective discusses recent progress in photon upconversion systems and devices for solar energy applications.
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Affiliation(s)
- Victor Gray
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- 412 96 Gothenburg, Sweden
| | - Damir Dzebo
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- 412 96 Gothenburg, Sweden
| | - Maria Abrahamsson
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- 412 96 Gothenburg, Sweden
| | - Bo Albinsson
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- 412 96 Gothenburg, Sweden
| | - Kasper Moth-Poulsen
- Department of Chemical and Biological Engineering
- Chalmers University of Technology
- 412 96 Gothenburg, Sweden
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Gray V, Lennartson A, Ratanalert P, Börjesson K, Moth-Poulsen K. Diaryl-substituted norbornadienes with red-shifted absorption for molecular solar thermal energy storage. Chem Commun (Camb) 2014; 50:5330-2. [DOI: 10.1039/c3cc47517d] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Abstract
BACKGROUND There is limited information on the causes of neurological disorders in an Australian rural setting. METHODS This study reports on a prospective cohort of 160 patients (95 women and 65 men) with a mean age of 55.1 years (standard deviation 19.78 years, range 12-92 years) receiving a neurological work-up from one neurologist attending the Geraldton and Midwest region of Western Australia over a 12-month period. RESULTS Patients were divided into 15 diagnostic classifications. Movement disorders were the most common diagnostic classification (38 of 160 or 23.75%) and Parkinson's disease was the most common movement disorder (30 of 38 or 78.95%) with an estimated period of prevalence of 187.5 persons per 1000. Of the other neurological disorder diagnosis classifications the following number of patients per group was observed: epilepsy (27 or 16.87%); neuromuscular disorders (22 or 13.75%); multiple sclerosis (12 or 7.5%); cerebrovascular disease (10 or 6.25%); headaches (7 or 4.37%); neurodegenerative (7 or 4.37%); dementias (6 or 3.75%); memory dysfunction (6 or 3.75%); gait disorders (4 or 2.5%); vestibular syndrome (3 or 1.87%); pain syndrome (3 or 1.87%); sensory syndrome (2 or 1.25%); brain injury (1 or 0.62%) and miscellaneous (12 or 7.5%). A high number of persons having Parkinson's disease was found. CONCLUSION Possible risk factors for Parkinson's disease for individuals living in Geraldton and Midwest region need to be investigated. This study raises issues pertaining to the provision of services and allocation of resources in rural areas, especially for patients with Parkinson's disease.
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Affiliation(s)
- P K Panegyres
- Neurodegenerative Disorders Research, Perth, Western Australia, Australia.
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Thompson LJ, Gray V, Lindsay D, von Holy A. Carbon : nitrogen : phosphorus ratios influence biofilm formation byEnterobacter cloacaeandCitrobacter freundii. J Appl Microbiol 2006; 101:1105-13. [PMID: 17040234 DOI: 10.1111/j.1365-2672.2006.03003.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
AIMS To test the effects of C : N : P ratio modification of a well-known nutrient medium formulation, the Endo formulation on biofilm formation by Enterobacter cloacae Ecl and Citrobacter freundii Cf1 in both single-species and binary species biofilms. METHODS AND RESULTS The C : N : P atom : atom ratio of a well-known nutrient medium formulation, the Endo formulation, that has been applied in fermentative biohydrogen studies, was modified to include two different C concentrations, one containing 17.65 g l(-1) and the other 8.84 g l(-1) sucrose, each containing four different C : N : P ratios, two at higher C : N : P ratios (334 : 84 : 16.8 and 334 : 84 : 3) and two at lower C : N : P ratios (334 : 28 : 5.6 and 334 : 28 : 1). Attached cells were enumerated after dislodging the biofilms that had formed on granular activated carbon (GAC). The modified medium containing 17.65 g l(-1) sucrose and having a C : N : P ratio of 334 : 28 : 5.6 resulted in significantly (P < 0.05) higher counts of attached cells for both single-species biofilms at 7.73 log(10) CFU g(-1) GAC and 9.3 log(10)CFU g(-1) GAC for Ent. cloacae Ecl and Cit. freundii Cf1, respectively, and binary species biofilms at 8.2 log(10) CFU g(-1) GAC and 6.34 log(10) CFU g(-1) GAC for Ent. cloacae Ecl and Cit. freundii Cf1, respectively. Scanning electron micrographs showed qualitative evidence that the 334 : 28 : 5.6 ratio encouraged more complex and extensive biofilm growth for both single-species and binary species biofilms. CONCLUSIONS The differences in the attachment numbers between the different ratios were found not to be a result of the individual actions of the bacterial isolates involved but rather because of the effects of the various C : N : P ratios. The 334 : 28 : 5.6 ratio showed significantly (P < 0.05) higher counts of attached cells for both single-species and binary species biofilms. SIGNIFICANCE AND IMPACT OF THE STUDY This study indicates that C : N : P ratios should be a key consideration with regard to maximizing biofilm formation in shake flask and fluidized bed bioreactor studies as well as understanding fundamental factors affecting biofilm growth in natural environments.
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Affiliation(s)
- L J Thompson
- School of Molecular and Cell Biology, University of the Witwatersrand, Gauteng, South Africa
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Abstract
We developed a rapid and reliable PCR assay with genus-specific primers for the detection of Salmonella in food samples. With these primers, no primer-specific amplicons were detected when challenged with cultures of microorganisms other than salmonellae, and positive results, i.e., Salmonella-specific bands, were obtained with pure cultures of all 125 Salmonella isolates tested, which represented 100 serovars. The PCR assay was optimized using both pure cultures and artificially inoculated food samples. The assay results were compared with those of the Australian standard culture methods, using more than 500 "naturally" contaminated food samples, over a period of 9 years. Food samples were subjected to nonselective preenrichment in buffered peptone water followed by selective enrichment in Rappaport Vassiliadis (RV) broth and mannitol selenite cystine (MSC) broth. A simple sample preparation method was developed based on concentrating bacterial cells from 1 ml of RV or MSC broths. The PCR results were in perfect agreement with the results of the standard culture methods; no false-positive or false-negative results were obtained. However, the PCR assay was extremely rapid, and results could be obtained within 4 h of testing of enrichment broths.
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Affiliation(s)
- N S Bansal
- Institute of Clinical Pathology and Medical Research, Division of Analytical Laboratories, Western Sydney Area Health Services, Lidcombe, New South Wales, Australia.
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Marotta A, Tan C, Gray V, Malik S, Gallinger S, Sanghera J, Dupuis B, Owen D, Dedhar S, Salh B. Dysregulation of integrin-linked kinase (ILK) signaling in colonic polyposis. Oncogene 2001; 20:6250-7. [PMID: 11593435 DOI: 10.1038/sj.onc.1204791] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2001] [Revised: 06/26/2001] [Accepted: 07/05/2001] [Indexed: 12/21/2022]
Abstract
Mutation of the adenomatous polyposis coli (APC) gene and the subsequent dysregulation of beta-catenin are well-documented abnormalities in familial adenomatous polyposis (FAP), as well as sporadic polyposis. Intriguingly, overexpression of the integrin-linked kinase (ILK) has been shown to modulate beta-catenin subcellular localization and function. However, the significance of this finding for human carcinogenesis remains unclear. Here, we report the increased biochemical activity and expression of ILK protein in polyps from FAP patients. Furthermore, dramatic increases in ILK immunoreactivity were observed in all abnormal crypts from sporadic polyps, when compared with the normal appearing crypts within the same resected specimens. As sulindac and aspirin are the two most important therapeutic/chemopreventative agents demonstrated in colorectal carcinogenesis, in both humans and animals, further investigation revealed that these non-steroidal anti-inflammatory drugs (NSAIDs) target ILK and ILK-mediated events in vivo. These include inhibition of, both the biochemical activation of ILK, inhibition of serine 9 GSK3beta phosphorylation and the enhancement of TCF-4 transcriptional activity. In conclusion, ILK protein hyperexpression appears to be an early event in colonic polyposis. Additionally, ILK signaling is shown to undergo modulation by sulindac (and aspirin) for the first time, indicating that it is likely to be one of the targets affected by these agents in vivo.
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Affiliation(s)
- A Marotta
- Jack Bell Research Center, 2660 Oak Street, Vancouver, BC, Canada V6H 3Z6
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Persad S, Attwell S, Gray V, Mawji N, Deng JT, Leung D, Yan J, Sanghera J, Walsh MP, Dedhar S. Regulation of protein kinase B/Akt-serine 473 phosphorylation by integrin-linked kinase: critical roles for kinase activity and amino acids arginine 211 and serine 343. J Biol Chem 2001; 276:27462-9. [PMID: 11313365 DOI: 10.1074/jbc.m102940200] [Citation(s) in RCA: 385] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Protein kinase B (PKB/Akt) is a regulator of cell survival and apoptosis. To become fully activated, PKB/Akt requires phosphorylation at two sites, threonine 308 and serine 473, in a phosphatidylinositol (PI) 3-kinase-dependent manner. The kinase responsible for phosphorylation of threonine 308 is the PI 3-kinase-dependent kinase-1 (PDK-1), whereas phosphorylation of serine 473 has been suggested to be regulated by PKB/Akt autophosphorylation in a PDK-1-dependent manner. However, the integrin-linked kinase (ILK) has also been shown to regulate phosphorylation of serine 473 in a PI 3-kinase-dependent manner. Whether ILK phosphorylates this site directly or functions as an adapter molecule has been debated. We now show by in-gel kinase assay and matrix-assisted laser desorption-ionization time-of-flight mass spectrometry that biochemically purified ILK can phosphorylate PKB/Akt directly. Co-immunoprecipitation analysis of cell extracts demonstrates that ILK can complex with PKB/Akt as well as PDK-1 and that ILK can disrupt PDK-1/PKB association. The amino acid residue serine 343 of ILK within the activation loop is required for kinase activity as well as for its interaction with PKB/Akt. Mutational analysis of ILK further shows a crucial role for arginine 211 of ILK within the phosphoinositide phospholipid binding domain in the regulation of PKB- serine 473 phosphorylation. A highly selective small molecule inhibitor of ILK activity also inhibits the ability of ILK to phosphorylate PKB/Akt in vitro and in intact cells. These data demonstrate that ILK is an important upstream kinase for the regulation of PKB/Akt.
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Affiliation(s)
- S Persad
- British Columbia Cancer Agency, Vancouver Hospital Health Sciences Centre, Jack Bell Research Centre, Vancouver, British Columbia V6H 3Z6, Canada
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Gray V. Care of older people. Prof Nurse 2001; 16:1331. [PMID: 12026824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/18/2023]
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Aubry AF, Sebastian D, Hobson T, Xu JQ, Rabel S, Xie M, Gray V. In-use testing of extemporaneously prepared suspensions of second generation non-nucleoside reversed transcriptase inhibitors in support of phase I clinical studies. J Pharm Biomed Anal 2000; 23:535-42. [PMID: 10933547 DOI: 10.1016/s0731-7085(00)00337-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
DPC 961 and 963 are two of a series of prospective second generation non-nucleoside reverse transcriptase inhibitors (NNRTIs) being considered for the treatment of HIV infections. The 'powder in a bottle' approach was used for drug administration for Phase I clinical studies. This new approach consists of compounding the active drug as a suspension or solution at the clinical site immediately before dosing. Prior to clinical use, studies were conducted to determine the compatibility of the drugs with the suspending agent, the recovery of the drugs using the administration procedure and the dissolution profile of the suspensions. The stability of the DPC 961 and 963 in the dosing formulation was followed over a 24-h period using a stability indicating HPLC method. In addition, the dissolution profiles of the suspensions were established for future comparison with solid dosage forms. Although the two drugs have very similar chemical structures, they clearly exhibited different behaviors in liquid/liquid extraction and dissolution experiments. These differences could be related to the physical characteristics of the powders, such as particle size and surface area. The results of the in-use testing of the suspension showed adequate recovery of the drugs from the bottle at two drug levels. The stability of DPC 961 and 963 in the suspending agent was sufficient for constitution and administration of the suspensions at the clinical site.
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Affiliation(s)
- A F Aubry
- Pharmaceutical Research and Development Experimental Station, DuPont Pharmaceuticals Company, Wilmington, DE 19880-0353, USA
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Persad S, Attwell S, Gray V, Delcommenne M, Troussard A, Sanghera J, Dedhar S. Inhibition of integrin-linked kinase (ILK) suppresses activation of protein kinase B/Akt and induces cell cycle arrest and apoptosis of PTEN-mutant prostate cancer cells. Proc Natl Acad Sci U S A 2000; 97:3207-12. [PMID: 10716737 PMCID: PMC16217 DOI: 10.1073/pnas.97.7.3207] [Citation(s) in RCA: 264] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
PTEN is a tumor suppressor gene located on chromosome 10q23 that encodes a protein and phospholipid phosphatase. Somatic mutations of PTEN are found in a number of human malignancies, and loss of expression, or mutational inactivation of PTEN, leads to the constitutive activation of protein kinase B (PKB)/Akt via enhanced phosphorylation of Thr-308 and Ser-473. We recently have demonstrated that the integrin-linked kinase (ILK) can phosphorylate PKB/Akt on Ser-473 in a phosphoinositide phospholipid-dependent manner. We now demonstrate that the activity of ILK is constitutively elevated in a serum- and anchorage-independent manner in PTEN-mutant cells, and transfection of wild-type (WT) PTEN into these cells inhibits ILK activity. Transfection of a kinase-deficient, dominant-negative form of ILK or exposure to a small molecule ILK inhibitor suppresses the constitutive phosphorylation of PKB/Akt on Ser-473, but not on Thr-308, in the PTEN-mutant prostate carcinoma cell lines PC-3 and LNCaP. Transfection of dominant-negative ILK and WT PTEN into these cells also results in the inhibition of PKB/Akt kinase activity. Furthermore, dominant-negative ILK or WT PTEN induces G(1) phase cycle arrest and enhanced apoptosis. Together, these data demonstrate a critical role for ILK in PTEN-dependent cell cycle regulation and survival and indicate that inhibition of ILK may be of significant value in PTEN-mutant tumor therapy.
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Affiliation(s)
- S Persad
- British Columbia Cancer Agency and Jack Bell Research Centre, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada
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Delcommenne M, Tan C, Gray V, Rue L, Woodgett J, Dedhar S. Phosphoinositide-3-OH kinase-dependent regulation of glycogen synthase kinase 3 and protein kinase B/AKT by the integrin-linked kinase. Proc Natl Acad Sci U S A 1998; 95:11211-6. [PMID: 9736715 PMCID: PMC21621 DOI: 10.1073/pnas.95.19.11211] [Citation(s) in RCA: 874] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Integrin-linked kinase (ILK) is an ankyrin-repeat containing serine-threonine protein kinase capable of interacting with the cytoplasmic domains of integrin beta1, beta2, and beta3 subunits. Overexpression of ILK in epithelial cells disrupts cell-extracellular matrix as well as cell-cell interactions, suppresses suspension-induced apoptosis (also called Anoikis), and stimulates anchorage-independent cell cycle progression. In addition, ILK induces nuclear translocation of beta-catenin, where the latter associates with a T cell factor/lymphocyte enhancer-binding factor 1 (TCF/LEF-1) to form an activated transcription factor. We now demonstrate that ILK activity is rapidly, but transiently, stimulated upon attachment of cells to fibronectin, as well as by insulin, in a phosphoinositide-3-OH kinase [Pi(3)K]-dependent manner. Furthermore, phosphatidylinositol(3,4,5)trisphosphate specifically stimulates the activity of ILK in vitro, and in addition, membrane targetted constitutively active Pi(3)K activates ILK in vivo. We also demonstrate here that ILK is an upstream effector of the Pi(3)K-dependent regulation of both protein kinase B (PKB/AKT) and glycogen synthase kinase 3 (GSK-3). Specifically, ILK can directly phosphorylate GSK-3 in vitro and when stably, or transiently, overexpressed in cells can inhibit GSK-3 activity, whereas the overexpression of kinase-deficient ILK enhances GSK-3 activity. In addition, kinase-active ILK can phosphorylate PKB/AKT on serine-473, whereas kinase-deficient ILK severely inhibits endogenous phosphorylation of PKB/AKT on serine-473, demonstrating that ILK is involved in agonist stimulated, Pi(3)K-dependent, PKB/AKT activation. ILK is thus a receptor-proximal effector for the Pi(3)K-dependent, extracellular matrix and growth factor mediated, activation of PKB/AKT, and inhibition of GSK-3.
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Affiliation(s)
- M Delcommenne
- British Columbia Cancer Agency, Jack Bell Research Centre, 2660 Oak Street, Vancouver, British Columbia V6H 3Z6 Canada
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Affiliation(s)
- R Kohr
- London Health Sciences Centre, Ontario
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