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Novel Organometallic Complexes and Polymers Based Luminescent Materials

English title Novel Organometallic Complexes and Polymers Based Luminescent Materials
Applicant Venkatesan Koushik
Number 135488
Funding scheme Project funding (Div. I-III)
Research institution Institut für Chemie Universität Zürich
Institution of higher education University of Zurich - ZH
Main discipline Inorganic Chemistry
Start/End 01.02.2012 - 31.01.2015
Approved amount 186'910.00
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All Disciplines (2)

Discipline
Inorganic Chemistry
Organic Chemistry

Keywords (4)

Polymers; light emitting devices; Organometallic small molecules ; Phosphorescence

Lay Summary (English)

Lead
Organometallic materials are of particular interest in applications that demand light emission, for example, as active materials in organic light-emitting diodes (OLEDs), optical sensors and sensor protectors. OLEDs are emerging as the leading technology for the new generation of full color flat panel display and lighting applications. Much of the research work done until now has relied on compounds consisting of cyclometalated Iridium(III) and Platinum(II) as part of the molecular scaffold. The wide dissipation of the OLED technology relies on the development of stable and highly efficient blue triplet emitting molecules and also in systems that can be solution processed, which would allow for easy deployment of large-scale manufacturing.
Lay summary

In this project, we have developed a new conceptual approach to achieve highly efficient and stable blue emitting platinum(II) compounds that do not have cyclometalation as part of the molecular scaffold. The initially fabricated OLED devices reveal these compounds as promising materials and further optimization of the device construction is on-going to accomplish high external quantum efficiencies. We have also identified a suitable molecular structure which will be used for the development of the polymers in the next phase of the project.  We had investigated into gold(III) cyclometalated compounds as an alternative to the existing iridium(III) and platinum(II). Luminescent gold(III) complexes is still at its infancy, however, we have developed monocyclometalated gold(III) compounds that have highly tunable and efficient emission properties. Although we have been able to address some aspects of the stability issues, further improvements in stability as well as emission efficiency is required, which is being pursued. Overall, the project has contributed new fundamental findings via creating a design paradigm that could aid the development of triplet emitters suitable for OLED devices and has set-up a strong base for the development of organometallic polymeric materials that will be highly valuable for application in the field of phosphorescent based organic light emitting devices (PHOLEDs), optical limiting materials and sensors.

Direct link to Lay Summary Last update: 12.03.2015

Responsible applicant and co-applicants

Employees

Publications

Publication
Monocyclometalated Gold(III) Complexes Bearing pi-Accepting Cyanide Ligands: Syntheses, Structural, Photophysical, and Electrochemical Investigations
Szentkuti Alexander, Garg Jai Anand, Blacque Olivier, Venkatesan Koushik (2015), Monocyclometalated Gold(III) Complexes Bearing pi-Accepting Cyanide Ligands: Syntheses, Structural, Photophysical, and Electrochemical Investigations, in INORGANIC CHEMISTRY, 54(22), 10748-10760.
Stable and color tunable emission properties based on non-cyclometalated gold(III) complexes
Bachmann Michael, Blacque Olivier, Venkatesan Koushik (2015), Stable and color tunable emission properties based on non-cyclometalated gold(III) complexes, in DALTON TRANSACTIONS, 44(21), 10003-10013.
Anticancer Profile of a Series of Gold(III) (2-phenyl)pyridine Complexes
Rubbiani Riccardo, Zehnder Thomas N., Mari Cristina, Blacque Olivier, Venkatesan Koushik, Gasser Gilles (2014), Anticancer Profile of a Series of Gold(III) (2-phenyl)pyridine Complexes, in CHEMMEDCHEM, 9(12), 2781-2790.
Luminescent monocyclometalated cationic gold(III) complexes: synthesis, photophysical characterization and catalytic investigations
Zehnder Thomas N., Blacque Olivier, Venkatesan Koushik (2014), Luminescent monocyclometalated cationic gold(III) complexes: synthesis, photophysical characterization and catalytic investigations, in DALTON TRANSACTIONS, 43(31), 11959-11972.
Monocyclometalated Gold(III) Monoaryl Complexes-A New Class of Triplet Phosphors with Highly Tunable and Efficient Emission Properties
Szentkuti Alexander, Bachmann Michael, Garg Jai Anand, Blacque Olivier, Venkatesan Koushik (2014), Monocyclometalated Gold(III) Monoaryl Complexes-A New Class of Triplet Phosphors with Highly Tunable and Efficient Emission Properties, in Chemistry - A European Journal, 2585-2596.
Tuning the Luminescent Properties of Pt(II) Acetylide Complexes through Varying the Electronic Properties of N-Heterocyclic Carbene Ligands
Zhang Yuzhen, Clavadetscher Jessica, Bachmann Michael, Blacque Olivier, Venkatesan Koushik (2014), Tuning the Luminescent Properties of Pt(II) Acetylide Complexes through Varying the Electronic Properties of N-Heterocyclic Carbene Ligands, in INORGANIC CHEMISTRY, 53(2), 756-771.
Highly Efficient Deep-Blue Emitters Based on cis and trans N-Heterocyclic Carbene Pt-II Acetylide Complexes: Synthesis, Photophysical Properties, and Mechanistic Studies
Zhang Yuzhen, Blacque Olivier, Venkatesan Koushik (2013), Highly Efficient Deep-Blue Emitters Based on cis and trans N-Heterocyclic Carbene Pt-II Acetylide Complexes: Synthesis, Photophysical Properties, and Mechanistic Studies, in CHEMISTRY-A EUROPEAN JOURNAL, 19(46), 15689-15701.
(Benzimidazolin-2-ylidene)-AuI-Alkynyl Complexes: Syntheses, Structure, and Photophysical Properties
Garg JA, Blacque O, Heier J, Venkatesan K (2012), (Benzimidazolin-2-ylidene)-AuI-Alkynyl Complexes: Syntheses, Structure, and Photophysical Properties, in EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, (11), 1750-1763.

Collaboration

Group / person Country
Types of collaboration
Prof. Trisha Andrew/ University of Wisconsin Madison United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
EMPA Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
248th American Chemical Society National Meeting, San Franscisco, USA, August 10-14, 2014 Talk given at a conference Rational Design Approaches to Next Generation Gold(III) Luminophores 10.08.2014 San Francisco, United States of America Venkatesan Koushik;
Young faculty meeting Individual talk Conceptual Design Approaches to Electronic Materials 05.06.2014 Bern, Switzerland Venkatesan Koushik;
9. Koordinationchemie treffen 2013 Talk given at a conference Investigations into neutral Gold(III) triplet phosphors 25.02.2013 Bayreuth, Germany Szentkuti Alexander; Venkatesan Koushik;
Swiss Chemical Society, Fall meeting Talk given at a conference Engineering Novel Gold(III) Luminophores 13.09.2012 Zurich, Switzerland Venkatesan Koushik;


Associated projects

Number Title Start Funding scheme
156967 Novel Organometallic Complexes and Polymers Based Luminescent Materials 01.02.2015 Project funding (Div. I-III)
144964 Upgrade of the UZH NMR Core Facility 01.12.2012 R'EQUIP

Abstract

The primary objective of this project is to investigate the syntheses and photophysical properties of platinum (Pt) and gold (Au) based organometallic complexes and conjugated polymers that could potentially lead to highly efficient luminescent materials. Emphasis will be laid on the development of new synthetic methodologies for preparing the proposed new compounds and polymers with novel structural features. Subsequently, extensive photophysical characterization would be carried out to obtain structure related properties that could aid in the development of new class of emissive materials. As specific objectives, we plan to synthesize and investigate the luminescent properties of a) Au(III) cyclometallated complexes and (b) Au(I) carbene complexes, (c) Platinum(II) carbene complexes and their conjugated polymers. These metal centers in specific oxidation states coupled with unique ligand environments would be utilized to tailor the emissive nature of the materials. Several strategies are herein proposed towards the improvement of luminescence efficiencies and tackle application oriented issues such as long-term thermal and photostability for these particular classes of materials. Design strategy is adopted in such a way so as to prepare novel phosphorescent small molecule entities, and later utilize the same with little structural modification for building polymers and correlate the properties of model compounds (small molecules) to polymers. The unique electronic properties that arise from conjugated polymers can be advantageously used for a variety of optoelectronic applications, with proper attention paid to the design of the polymers in order to obtain good properties both in solution and solid-state. A combination of luminescent properties and novel structures of the organometallic complexes and polymers could lead to potential applications in the field of phosphorescent based organic light emitting devices (PHOLEDs), optical limiting materials and sensors.
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