Thermally Activated Delayed Fluorescence (TADF) and Self-Healing Ultra-Stable Luminophores for Bioimaging

• Applicant: Dr. Rafal Czerwieniec
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Inorganic Molecular Chemistry - Synthesis and Characterisation ; Biomaterials ; Synthesis and Properties of Functional Materials ; Organic Molecular Chemistry - Synthesis and Characterisation
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 389797483

• Final Report Year: 2023

Final Report Abstract

The project aimed at the synthesis and photophysical characterization of chromophores with high emission quantum yields useful for applications in bioimaging, oxygen sensing, or OLEDs. In order to minimize the detrimental effects of blinking or photobleaching in fluorescence emitters, the “dark” triplet state should have a short lifetime and preferentially decay via temperature activated delayed fluorescence (TADF). The results can be grouped into three sub-projects: A) TADF compounds depopulate the “dark” triplet state of fluorescent emitters through thermal equilibrium with the emitting singlet state. In addition to two metal-organic prototypes, a family of organic compounds was synthesized by functionalising 2,5-di(N,N0- carbazolyl)terephthalonitrile or 2,3,5,6-tetra(N,N0-carbazolyl)terephthalonitrile with alkoxy chains. Their TADF properties were examined, and tested in an OLED device. B) Compounds with slow ISC rates can show fluorescence and phosphorescence simultaneously. We designed several binuclear metal-organic compounds with specific bridging ligands which show substantial emission quantum yields both for fluorescence and phosphorescence. The latter is readily quenched by oxygen, hence these compounds are potentially useful as oxygen sensors providing an intrinsic reference. C) Highly efficient phosphorescence emitters are useful for OLED applications, but could also be used for bioimaging. We presented more than 10 new compounds with quantum yields exceeding 85%, mostly by bringing two metal centers into resonance.

Publications

• Excited-State Switching between Ligand-Centered and Charge Transfer Modulated by Metal–Carbon Bonds in Cyclopentadienyl Iridium Complexes. Inorganic Chemistry, 57(24), 15445-15461.
  Deaton, Joseph C.; Taliaferro, Chelsea M.; Pitman, Catherine L.; Czerwieniec, Rafał; Jakubikova, Elena; Miller, Alexander J. M. & Castellano, Felix N.
  
• An efficient heterodinuclear Ir(iii)/Pt(ii) complex: synthesis, photophysics and application in light-emitting electrochemical cells. Journal of Materials Chemistry C, 7(34), 10672-10682.
  Shafikov, Marsel Z.; Tang, Shi; Larsen, Christian; Bodensteiner, Michael; Kozhevnikov, Valery N. & Edman, Ludvig
  
• Can Coumarins Break Kasha’s Rule?. The Journal of Physical Chemistry Letters, 10(21), 6468-6471.
  Shafikov, Marsel Z.; Brandl, Fabian; Dick, Bernhard & Czerwieniec, Rafał
  
• Design of a New Mechanism beyond Thermally Activated Delayed Fluorescence toward Fourth Generation Organic Light Emitting Diodes. Chemistry of Materials, 31(16), 6110-6116.
  Yersin, Hartmut; Mataranga-Popa, Larisa; Czerwieniec, Rafał & Dovbii, Yan
  
• Dinuclear Design of a Pt(II) Complex Affording Highly Efficient Red Emission: Photophysical Properties and Application in Solution-Processible OLEDs. ACS Applied Materials & Interfaces, 11(8), 8182-8193.
  Shafikov, Marsel Z.; Daniels, Ruth; Pander, Piotr; Dias, Fernando B.; Williams, J. A. Gareth & Kozhevnikov, Valery N.
  
• Luminescent pyrenyl-GNA nucleosides: synthesis, photophysics and confocal microscopy studies in cancer HeLa cells. Photochemical & Photobiological Sciences, 18(10), 2449-2460.
  Skiba, Joanna; Kowalczyk, Aleksandra; Fik, Marta A.; Gapiñska, Magdalena; Trzybiñski, Damian; Woźniak, Krzysztof; Vrček, Valerije; Czerwieniec, Rafai & Kowalski, Konrad
  
• Unusually Fast Phosphorescence from Ir(III) Complexes via Dinuclear Molecular Design. The Journal of Physical Chemistry Letters, 10(22), 7015-7024.
  Shafikov, Marsel Z.; Daniels, Ruth & Kozhevnikov, Valery N.
  
• Near Infrared Phosphorescent Dinuclear Ir(III) Complex Exhibiting Unusually Slow Intersystem Crossing and Dual Emissive Behavior. The Journal of Physical Chemistry Letters, 11(15), 5849-5855.
  Shafikov, Marsel Z.; Zaytsev, Andrey V.; Suleymanova, Alfiya F.; Brandl, Fabian; Kowalczyk, Aleksandra; Gapińska, Magdalena; Kowalski, Konrad; Kozhevnikov, Valery N. & Czerwieniec, Rafał
  
• Cyclometalation Geometry of the Bridging Ligand as a Tuning Tool for Photophysics of Dinuclear Ir(III) Complexes. The Journal of Physical Chemistry C, 125(37), 20531-20537.
  Shafikov, Marsel Z.; Zaytsev, Andrey V. & Kozhevnikov, Valery N.
  
• Dual emissive dinuclear Pt(ii) complexes and application to singlet oxygen generation. Journal of Materials Chemistry C, 9(17), 5808-5818.
  Shafikov, Marsel Z.; Suleymanova, Alfiya F.; Kutta, Roger J.; Brandl, Fabian; Gorski, Aleksander & Czerwieniec, Rafał
  
• Extended ligand conjugation and dinuclearity as a route to efficient platinum-based near-infrared (NIR) triplet emitters and solution-processed NIR-OLEDs. Journal of Materials Chemistry C, 9(1), 127-135.
  Shafikov, Marsel Z.; Pander, Piotr; Zaytsev, Andrey V.; Daniels, Ruth; Martinscroft, Ross; Dias, Fernando B.; Williams, J. A. Gareth & Kozhevnikov, Valery N.
  
• Halide-Enhanced Spin–Orbit Coupling and the Phosphorescence Rate in Ir(III) Complexes. Inorganic Chemistry, 60(2), 642-650.
  Shafikov, Marsel Z.; Zaytsev, Andrey V. & Kozhevnikov, Valery N.
  
• Liquid-crystalline TADF materials based on substituted carbazoles and terephthalonitrile. Journal of Materials Chemistry C, 9(20), 6528-6535.
  Suleymanova, Alfiya F.; Shafikov, Marsel Z.; Whitwood, Adrian C.; Czerwieniec, Rafał & Bruce, Duncan W.
  
• Non-Stereogenic Dinuclear Ir(III) Complex with a Molecular Rack Design to Afford Efficient Thermally Enhanced Red Emission. Inorganic Chemistry, 60(3), 1780-1789.
  Shafikov, Marsel Z.; Martinscroft, Ross; Hodgson, Craig; Hayer, Anna; Auch, Armin & Kozhevnikov, Valery N.
  
• Synthesis and structural characterization of bis-cyclometalated compounds [Ir(dFppy)2(Me4phen)]PF6 and [Ir(dF(CF3)ppy)2(Me4phen)]PF6. Inorganica Chimica Acta, 527, 120554.
  Graf, Marion; Czerwieniec, Rafał; Mayer, Peter & Böttcher, Hans-Christian
  
• Applications of Metal Complexes in Organic Light-Emitting Diodes (Oleds). Springer Handbooks, 1737-1775. Springer International Publishing.
  Czerwieniec, Rafał
  
• Benzannulation of a ditopic ligand to afford mononuclear and dinuclear Ir(iii) complexes with intense phosphorescence: applications in singlet oxygen generation and bioimaging. Journal of Materials Chemistry C, 10(5), 1870-1877.
  Shafikov, Marsel Z.; Hodgson, Craig; Gorski, Aleksander; Kowalczyk, Aleksandra; Gapińska, Magdalena; Kowalski, Konrad; Czerwieniec, Rafał & Kozhevnikov, Valery N.
  
• Chemistry of glycol nucleic acid (GNA): Synthesis, photophysical characterization and insight into the biological activity of phenanthrenyl GNA constituents. Bioorganic Chemistry, 125, 105847.
  Kowalczyk, Aleksandra; Piotrowicz, Michał; Gapińska, Magdalena; Trzybiński, Damian; Woźniak, Krzysztof; Golding, Taryn M.; Stringer, Tameryn; Smith, Gregory S.; Czerwieniec, Rafał & Kowalski, Konrad
  
• Construction and performance of OLED devices prepared from liquid-crystalline TADF materials. Physical Chemistry Chemical Physics, 24(36), 22115-22121.
  Suleymanova, Alfiya F.; Shafikov, Marsel Z.; Chen, Xinrui; Wang, Yafei; Czerwieniec, Rafal & Bruce, Duncan W.
  
• Ligand design and nuclearity variation towards dual emissive Pt(ii) complexes for singlet oxygen generation, dual channel bioimaging, and theranostics. Journal of Materials Chemistry C, 10(14), 5636-5647.
  Shafikov, Marsel Z.; Suleymanova, Alfiya F.; Kutta, Roger J.; Gorski, Alexander; Kowalczyk, Aleksandra; Gapińska, Magdalena; Kowalski, Konrad & Czerwieniec, Rafał
  
• Aligning π-Extended π-Deficient Ligands to Afford Submicrosecond Phosphorescence Radiative Decay Time of Mononuclear Ir(III) Complexes. Inorganic Chemistry, 62(2), 810-822.
  Shafikov, Marsel Z.; Zaytsev, Andrey V.; Kozhevnikov, Valery N. & Czerwieniec, Rafał