Skip to main content

Research Repository

Advanced Search

Outputs (123)

Sonocrystallization induced thermally activated delayed fluorescence via distortion of molecular geometry † (2024)
Journal Article
Maggiore, A., Qu, Y., Pander, P., Dias, F. B., Clavier, G., Guillot, R., …Miomandre, F. (2024). Sonocrystallization induced thermally activated delayed fluorescence via distortion of molecular geometry †. Journal of Materials Chemistry C Materials for optical and electronic devices, https://doi.org/10.1039/d4tc00245h

In this work, we present three donor–acceptor thermally activated delayed fluorescence (TADF) molecules comprising a 2,3,5,6-tetrafluorobenzonitrile acceptor with various electron donor units: phenoxazine (Phx-BzN), phenothiazine (Pht-BzN), and carba... Read More about Sonocrystallization induced thermally activated delayed fluorescence via distortion of molecular geometry †.

Slow magnetic relaxation and luminescence properties in β-diketonate lanthanide( iii ) complexes. Preparation of Eu( iii ) and Yb( iii ) OLED devices † (2024)
Journal Article
Tubau, À., Rodríguez, L., Pander, P., Weatherill, L., Dias, F. B., Font-Bardía, M., & Vicente, R. (2024). Slow magnetic relaxation and luminescence properties in β-diketonate lanthanide( iii ) complexes. Preparation of Eu( iii ) and Yb( iii ) OLED devices †. Journal of Materials Chemistry C Materials for optical and electronic devices, https://doi.org/10.1039/d4tc00902a

The reaction of [Ln(btfa)3(H2O)2] (btfa− = 4,4,4-trifluoro-1-phenyl-1,3-butanedionate) with 4,4′-dinonyl-2,2′-bipyridyl (4,4′-dinonylbipy) in ethanol allows isolation of mononuclear complexes [Ln(btfa)3(4,4′-dinonylbipy)] Ln = Sm (1-Sm), Eu (2-Eu), T... Read More about Slow magnetic relaxation and luminescence properties in β-diketonate lanthanide( iii ) complexes. Preparation of Eu( iii ) and Yb( iii ) OLED devices †.

9-Borafluoren-9-yl and diphenylboron tetracoordinate complexes of 8-quinolinolato ligands with heavy-atoms substituents: synthesis, fluorescence and application in OLED devices (2024)
Journal Article
Fialho, C. B., Cruz, T., Calhorda, M., Vieira Ferreira, L., Pander, P., Dias, F. B., …Gomes, P. (2024). 9-Borafluoren-9-yl and diphenylboron tetracoordinate complexes of 8-quinolinolato ligands with heavy-atoms substituents: synthesis, fluorescence and application in OLED devices. Dyes and Pigments, 112174. https://doi.org/10.1016/j.dyepig.2024.112174

This work describes the synthesis and characterisation of new tetrahedral boron complexes, incorporating bromine- or iodine-substituted 8-quinolinolato chelate chromophores connected to 9-borafluoren-9-yl or diphenylboron orthogonal fragments. The mo... Read More about 9-Borafluoren-9-yl and diphenylboron tetracoordinate complexes of 8-quinolinolato ligands with heavy-atoms substituents: synthesis, fluorescence and application in OLED devices.

Nanostructured Channel for Improving Emission Efficiency of Hybrid Light-Emitting Field-Effect Transistors (2023)
Journal Article
Galán-González, A., Pander, P., MacKenzie, R. C. I., Bowen, L., Zeze, D. A., Borthwick, R. J., …Chaudhry, M. U. (2023). Nanostructured Channel for Improving Emission Efficiency of Hybrid Light-Emitting Field-Effect Transistors. ACS Photonics, 10(12), 4315-4321. https://doi.org/10.1021/acsphotonics.3c01080

We report on the mechanism of enhancing the luminance and external quantum efficiency (EQE) by developing nanostructured channels in hybrid (organic/inorganic) light-emitting transistors (HLETs) that combine a solution-processed oxide and a polymer h... Read More about Nanostructured Channel for Improving Emission Efficiency of Hybrid Light-Emitting Field-Effect Transistors.

Thermally activated delayed fluorescence in a deep red dinuclear iridium( iii ) complex: a hidden mechanism for short luminescence lifetimes † (2023)
Journal Article
Pander, P., Zaytsev, A. V., Sil, A., Baryshnikov, G. V., Siddique, F., Williams, J. A. G., …Kozhevnikov, V. N. (2023). Thermally activated delayed fluorescence in a deep red dinuclear iridium( iii ) complex: a hidden mechanism for short luminescence lifetimes †. Chemical Science, 14, 13934-13943. https://doi.org/10.1039/d3sc04450e

The high luminescence efficiency of cyclometallated iridium(iii) complexes, including those widely used in OLEDs, is typically attributed solely to the formally spin-forbidden phosphorescence process being facilitated by spin–orbit coupling with the... Read More about Thermally activated delayed fluorescence in a deep red dinuclear iridium( iii ) complex: a hidden mechanism for short luminescence lifetimes †.

Unusual Excimer/Dimer Behavior of a Highly Soluble C,N Platinum(II) Complex with a Spiro-Fluorene Motif. (2023)
Journal Article
Pander, P., Zaytsev, A. V., Franca, L. G., Dias, F. B., & Kozhevnikov, V. N. (2023). Unusual Excimer/Dimer Behavior of a Highly Soluble C,N Platinum(II) Complex with a Spiro-Fluorene Motif. Inorganic Chemistry, 62, 18465 - 18473. https://doi.org/10.1021/acs.inorgchem.3c02667

In this work, we introduce a spiro-fluorene unit into a phenylpyridine (CN)-type ligand as a simple way to deplanarize the structure and increase the solubility of the final platinum(II)···complex. Using a spiro-fluorene unit, orthogonal to the main... Read More about Unusual Excimer/Dimer Behavior of a Highly Soluble C,N Platinum(II) Complex with a Spiro-Fluorene Motif..

Rigidly linked dinuclear platinum( ii ) complexes showing intense, excimer-like, near-infrared luminescence (2023)
Journal Article
Pander, P., Walden, M. T., Salthouse, R. J., Sil, A., Yufit, D. S., Dias, F. B., & Williams, J. A. G. (2023). Rigidly linked dinuclear platinum( ii ) complexes showing intense, excimer-like, near-infrared luminescence. Journal of Materials Chemistry C Materials for optical and electronic devices, 11(43), 15335-15346. https://doi.org/10.1039/d3tc03432a

Many luminescent platinum(ii) complexes undergo face-to-face interactions between neighbouring molecules, leading to bimolecular excited states that may emit at lower energy (dimers and/or excimers). Detailed photophysical studies are reported on din... Read More about Rigidly linked dinuclear platinum( ii ) complexes showing intense, excimer-like, near-infrared luminescence.

9-Borafluoren-9-yl and diphenylboron tetracoordinate complexes of F- and Cl-substituted 8-quinolinolato ligands: synthesis, molecular and electronic structures, fluorescence and application in OLED devices (2023)
Journal Article
Fialho, C. B., Cruz, T. F. C., Rodrigues, A. I., Calhorda, M. J., Vieira Ferreira, L. F., Dias, F. B., …Gomes, P. T. (2023). 9-Borafluoren-9-yl and diphenylboron tetracoordinate complexes of F- and Cl-substituted 8-quinolinolato ligands: synthesis, molecular and electronic structures, fluorescence and application in OLED devices. Dalton Transactions, 52(15), 4933-4953. https://doi.org/10.1039/d3dt00496a

Six new four-coordinate tetrahedral boron complexes, containing 9-borafluoren-9-yl and diphenylboron cores attached to orthogonal fluorine- and chlorine-substituted 8-quinolinolato ligand chromophores, have been synthesised, characterised, and applie... Read More about 9-Borafluoren-9-yl and diphenylboron tetracoordinate complexes of F- and Cl-substituted 8-quinolinolato ligands: synthesis, molecular and electronic structures, fluorescence and application in OLED devices.

Zinc Phthalocyanine Sensing Mechanism Quantification for Potential Application in Chemical Warfare Agent Detectors (2022)
Journal Article

Rapid and accurate detection of lethal volatile compounds is an emerging requirement to ensure the security of the current and future society. Since the threats are becoming more complex, the assurance of future sensing devices’ performance can be ob... Read More about Zinc Phthalocyanine Sensing Mechanism Quantification for Potential Application in Chemical Warfare Agent Detectors.

Near-infrared electroluminescence beyond 940 nm in Pt(N^C^N)X complexes: influencing aggregation with the ancillary ligand X (2022)
Journal Article

We present a study of aggregate excited states formed by complexes of the type Pt(N^C^N)X, where N^C^N represents a tridentate cyclometallating ligand, and X = SCN or I. These materials display near-infrared (NIR) photoluminescence in film and electr... Read More about Near-infrared electroluminescence beyond 940 nm in Pt(N^C^N)X complexes: influencing aggregation with the ancillary ligand X.

Excimer or aggregate? Near infrared electro- and photoluminescence from multimolecular excited states of N^C^N-coordinated platinum(ii) complexes (2022)
Journal Article

We present an experimental and theoretical study of aggregate excited states formed by complexes of the type Pt(N^C^N)Cl, which display near-infrared (NIR) photoluminescence in film and NIR electroluminescence in OLED devices. Here, N^C^N represents... Read More about Excimer or aggregate? Near infrared electro- and photoluminescence from multimolecular excited states of N^C^N-coordinated platinum(ii) complexes.

Novel Easy to Synthesize Benzonitrile Compounds with Mixed Carbazole and Phenoxazine Substituents Exhibiting Dual Emission and TADF Properties (2022)
Journal Article

The photophysical and electrochemical properties of a new class of fluorinated benzonitrile compounds substituted with mixed phenoxazine and carbazole units have been investigated. When absorbing in a large range of the UV–vis spectrum due to both lo... Read More about Novel Easy to Synthesize Benzonitrile Compounds with Mixed Carbazole and Phenoxazine Substituents Exhibiting Dual Emission and TADF Properties.

TADF dendronized polymer with vibrationally enhanced direct spin-flip between charge-transfer states for efficient non-doped solution-processed OLEDs (2022)
Journal Article

A novel type of thermally activated delayed fluorescence (TADF) dendronized polymer was designed and synthesized. Firstly, one side of the asymmetric TADF unit was encapsulated by 3,6-di-tert-butylcarbazole via a conjugated linkage with strong twiste... Read More about TADF dendronized polymer with vibrationally enhanced direct spin-flip between charge-transfer states for efficient non-doped solution-processed OLEDs.

Asymmetrical‐Dendronized TADF Emitters for Efficient Non‐doped Solution‐Processed OLEDs by Eliminating Degenerate Excited States and Creating Solely Thermal Equilibrium Routes (2022)
Journal Article

Two asymmetric “half-dendronized” and “half-dendronized-half-encapsulated” TADF emitters eliminate degenerate excited states, assuring a solely thermal equilibrium route for an effective spin-flip process. AEE properties can minimize the exciton quen... Read More about Asymmetrical‐Dendronized TADF Emitters for Efficient Non‐doped Solution‐Processed OLEDs by Eliminating Degenerate Excited States and Creating Solely Thermal Equilibrium Routes.

Applying TADF Emitters in Bioimaging and Sensing—A Novel Approach Using Liposomes for Encapsulation and Cellular Uptake (2021)
Journal Article

A new method for facilitating the delivery, uptake and intracellular localisation of thermally activated delayed fluorescence (TADF) complexes was developed. First, confinement of TADF complexes in liposomes was demonstrated, which were subsequently... Read More about Applying TADF Emitters in Bioimaging and Sensing—A Novel Approach Using Liposomes for Encapsulation and Cellular Uptake.

The Role of Dinuclearity in Promoting Thermally Activated Delayed Fluorescence (TADF) in Cyclometallated, N^C^N-coordinated Platinum(II) Complexes (2021)
Journal Article

In this work we present synthesis and an in-depth photophysical analysis of a di-Pt(II) complex with a ditopic bis-N^C^N ligand. The complex exhibits a dual luminescent behaviour by emitting simultaneously delayed fluorescence and phosphorescence. By... Read More about The Role of Dinuclearity in Promoting Thermally Activated Delayed Fluorescence (TADF) in Cyclometallated, N^C^N-coordinated Platinum(II) Complexes.

Intramolecular interchromophore singlet-singlet and triplet-singlet energy transfer in a metal-free donor-acceptor emitter (2021)
Journal Article

In this work we demonstrate the occurrence of singlet to singlet, and triplet to singlet, intramolecular energy transfer between two thiophene-comprising donors (D) and a central perylene bisimide acceptor (A) covalently linked to each other trough a... Read More about Intramolecular interchromophore singlet-singlet and triplet-singlet energy transfer in a metal-free donor-acceptor emitter.

Acridone-amine D-A-D thermally activated delayed fluorescence emitters with narrow resolved electroluminescence and their electrochromic properties (2021)
Journal Article

Acridones have found their role in luminescent materials for OLEDs. Most interestingly, showing potential as weak charge transfer thermally activated delayed fluorescence (TADF) emitters, providing narrow photoluminescence. In this work, we present a... Read More about Acridone-amine D-A-D thermally activated delayed fluorescence emitters with narrow resolved electroluminescence and their electrochromic properties.

Exceptionally Fast Radiative Decay of a Dinuclear Platinum Complex Through Thermally Activated Delayed Fluorescence (2021)
Journal Article

A novel dinuclear platinum(II) complex featuring a ditopic, bis-tetradentate ligand has been prepared. The ligand offers each metal ion a planar O^N^C^N coordination environment, with the two metal ions bound to the nitrogen atoms of a bridging pyrim... Read More about Exceptionally Fast Radiative Decay of a Dinuclear Platinum Complex Through Thermally Activated Delayed Fluorescence.

Enhancement of thermally activated delayed fluorescence properties by substitution of ancillary halogen in a multiple resonance-like diplatinum(ii) complex (2021)
Journal Article

We present an in-depth investigation of the influence of chloro-to-iodo exchange on the thermally activated delayed fluorescence (TADF) of a dinuclear platinum(II) complex featuring monodentate halide ancillary ligands. The complexes are constructed... Read More about Enhancement of thermally activated delayed fluorescence properties by substitution of ancillary halogen in a multiple resonance-like diplatinum(ii) complex.

Cyclophane Molecules Exhibiting Thermally Activated Delayed Fluorescence: Linking Donor Units to Influence Molecular Conformation (2020)
Journal Article

The synthetic methodology to covalently link donors to form cyclophane-based thermally activated delayed fluorescence (TADF) molecules is presented. These are the first reported examples of TADF cyclophanes with “electronically innocent” bridges betw... Read More about Cyclophane Molecules Exhibiting Thermally Activated Delayed Fluorescence: Linking Donor Units to Influence Molecular Conformation.

Extended ligand conjugation and dinuclearity as a route to efficient platinum-based near-infrared (NIR) triplet emitters and solution-processed NIR-OLEDs (2020)
Journal Article

Near infrared (NIR) emission from molecular materials is typically targeted by using more extended conjugated systems compared to visible-emitting materials. But efficiencies usually fall off due to the combined effects of increasing non-radiative an... Read More about Extended ligand conjugation and dinuclearity as a route to efficient platinum-based near-infrared (NIR) triplet emitters and solution-processed NIR-OLEDs.

Benzannulation via the use of 1,2,4-triazines extends aromatic system of cyclometallated Pt(II) complexes to achieve candle light electroluminescence (2020)
Journal Article

This work describes an application of 1,2,4-triazine methodology for the synthesis of novel cyclometallated Pt (II) complexes of C^N type. It is shown that addition of a cyclopenteno unit into the complex structure not only facilitates the fabricatio... Read More about Benzannulation via the use of 1,2,4-triazines extends aromatic system of cyclometallated Pt(II) complexes to achieve candle light electroluminescence.

Luminescent halogen-substituted 2-(N-arylimino)pyrrolyl boron complexes: the internal heavy-atom effect (2020)
Journal Article

A group of new boron complexes [BPh2{2N,N’-NC4H3-2-C(H)=N-C6H4X}] (X= 4-Cl 4c, 4-Br 4d, 4-I 4e, 3-Br 4f, 2-Br 4g, 2-I 4h) containing different halogens as substituents in the N-aryl ring have been synthesized and characterized in terms of their mole... Read More about Luminescent halogen-substituted 2-(N-arylimino)pyrrolyl boron complexes: the internal heavy-atom effect.

Toward Efficient Toxic-Gas Detectors: Exploring Molecular Interactions of Sarin and Dimethyl Methylphosphonate with Metal-Centered Phthalocyanine Structures (2020)
Journal Article

The rapid and reliable detection of lethal agents such as sarin is of increasing importance. Here, density-functional theory (DFT) is used to compare the interaction of sarin with single-metal-centered phthalocyanine (MPc) and MPc layer structures to... Read More about Toward Efficient Toxic-Gas Detectors: Exploring Molecular Interactions of Sarin and Dimethyl Methylphosphonate with Metal-Centered Phthalocyanine Structures.

Donor-acceptor 1,2,4,5-Tetrazines Prepared by Buchwald-Hartwig Cross-Coupling Reaction and Their Photoluminescence Turn-on Property by Inverse Electron Demand Diels-Alder Reaction (2020)
Journal Article

A facile efficient synthetic tool, Buchwald-Hartwig cross-coupling reaction, for the functionalization of 1,2,4,5-tetrazines is presented. Important factors affecting the Buchwald-Hartwig cross-coupling reaction have been optimized. Seven new donor-a... Read More about Donor-acceptor 1,2,4,5-Tetrazines Prepared by Buchwald-Hartwig Cross-Coupling Reaction and Their Photoluminescence Turn-on Property by Inverse Electron Demand Diels-Alder Reaction.

Balancing charge-transfer strength and triplet states for deep-blue thermally activated delayed fluorescence with an unconventional electron rich dibenzothiophene acceptor (2019)
Journal Article

Manipulation of the emission properties of deep-blue emitters exhibiting thermally activated delayed fluorescence (TADF) through molecular design is challenging. We present an effective strategy to probe deeper into the role of localized (LE) and cha... Read More about Balancing charge-transfer strength and triplet states for deep-blue thermally activated delayed fluorescence with an unconventional electron rich dibenzothiophene acceptor.

Achieving Conformational Control in RTP and TADF Emitters by Functionalization of the Central Core (2019)
Journal Article

Three new symmetrical donor–acceptor–donor (D–A–D)-type molecules were prepared with phenothiazine (PTZ) as electron donors and 9,9-dimethylthioxanthene (TX) as the electron acceptor. The PTZ groups are attached at different positions on the acceptor... Read More about Achieving Conformational Control in RTP and TADF Emitters by Functionalization of the Central Core.

Impact of Methoxy Substituents on Thermally Activated Delayed Fluorescence and Room-Temperature Phosphorescence in All-Organic Donor–Acceptor Systems (2019)
Journal Article

Thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) are known to occur in organic D–A–D and D–A systems where the donor group contains the phenothiazine unit and the acceptor is dibenzothiophene-S,S-dioxide. Thi... Read More about Impact of Methoxy Substituents on Thermally Activated Delayed Fluorescence and Room-Temperature Phosphorescence in All-Organic Donor–Acceptor Systems.

Homoleptic platinum(ii) complexes with pyridyltriazole ligands: excimer-forming phosphorescent emitters for solution-processed OLEDs (2019)
Journal Article

Two new homoleptic platinum(II) complexes are reported that feature aryl-appended 5-(2-pyridyl)-1,2,4- triazole chelates acting as N^N ligating ions, PtL1 2 and PtL2 2. Readily prepared from easily accessible proligands, they offer good solubility in... Read More about Homoleptic platinum(ii) complexes with pyridyltriazole ligands: excimer-forming phosphorescent emitters for solution-processed OLEDs.

Realizing 20% External Quantum Efficiency in Electroluminescence with Efficient Thermally Activated Delayed Fluorescence from an Exciplex (2019)
Journal Article

Herein we report the investigation of non-doped exciplex formed in blends of 2,4,6-Tris[3-(diphenylphosphinyl)phenyl]-1,3,5-triazine (PO-T2T), working as the one-electron acceptor molecule, with different electron donors. The emission of these excipl... Read More about Realizing 20% External Quantum Efficiency in Electroluminescence with Efficient Thermally Activated Delayed Fluorescence from an Exciplex.

Blue TADF Emitters Based on Indenocarbazole Derivatives with High Photoluminescence and Electroluminescence Efficiencies (2019)
Journal Article

A series of blue thermally activated delayed fluorescence (TADF) emitters were designed and synthesized, using 2,4,6-triphenyl-1,3,5-triazine as the acceptor unit, and indenocarbazole derivatives as the electron-donating moiety. In contrast with othe... Read More about Blue TADF Emitters Based on Indenocarbazole Derivatives with High Photoluminescence and Electroluminescence Efficiencies.

Dinuclear Design of a Pt(II) Complex Affording Highly Efficient Red Emission: Photophysical Properties and Application in Solution-Processible OLEDs (2019)
Journal Article

The light-emitting efficiency of luminescent materials is invariably compromised on moving to the red and near-infrared regions of the spectrum due to the transfer of electronic excited-state energy into vibrations. We describe how this undesirable “... Read More about Dinuclear Design of a Pt(II) Complex Affording Highly Efficient Red Emission: Photophysical Properties and Application in Solution-Processible OLEDs.

Dynamics of aggregated states resolved by gated fluorescence in films of room temperature phosphorescent emitters (2019)
Journal Article

Phenazine derivative molecules were studied using steady state and time resolved fluorescence techniques and demonstrated to lead to strong formation of aggregated species, identified as dimers by time dependent density functional theory calculations... Read More about Dynamics of aggregated states resolved by gated fluorescence in films of room temperature phosphorescent emitters.

Time-resolved Photophysical Characterization of Triplet-Harvesting Organic Compounds at Oxygen-Free Environment Using an iCCD Camera (2018)
Journal Article

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables the acquisition of photoluminescence spectra covering the time regime from nanoseconds up to 0.1... Read More about Time-resolved Photophysical Characterization of Triplet-Harvesting Organic Compounds at Oxygen-Free Environment Using an iCCD Camera.

An iminodibenzyl–quinoxaline–iminodibenzyl scaffold as a mechanochromic and dual emitter: donor and bridge effects on optical properties (2018)
Journal Article

The influence of phenyl linkage and donor strength on the photophysical properties of new derivatives of quinoxaline-containing iminodibenzyl and iminostilbene moieties is studied. The donor–acceptor derivatives showed dual thermally activated delaye... Read More about An iminodibenzyl–quinoxaline–iminodibenzyl scaffold as a mechanochromic and dual emitter: donor and bridge effects on optical properties.

Intramolecular Charge Transfer Controls Switching Between Room Temperature Phosphorescence and Thermally Activated Delayed Fluorescence (2018)
Journal Article

Chemical modification of phenothiazine–benzophenone derivatives is shown to tune the emission behavior from triplet states by selecting the molecular geometry of the intramolecular charge transfer (ICT) state. A fundamental principle of planar ICT (P... Read More about Intramolecular Charge Transfer Controls Switching Between Room Temperature Phosphorescence and Thermally Activated Delayed Fluorescence.

Bond Rotations and Heteroatom Effects in Donor-Acceptor-Donor Molecules: Implications for Thermally Activated Delayed Fluorescence and Room Temperature Phosphorescence (2018)
Journal Article

The synthesis of 1-methylphenoxazine via CO2-directed lithiation chemistry is reported. This electron donor was coupled with 2,8-dibenzothiophene-S,S-dioxide with Buchwald–Hartwig chemistry to give a new D–A–D charge-transfer fluorescent molecule 1b.... Read More about Bond Rotations and Heteroatom Effects in Donor-Acceptor-Donor Molecules: Implications for Thermally Activated Delayed Fluorescence and Room Temperature Phosphorescence.

Observation of Dual Room Temperature Fluorescence-Phosphorescence in Air, in the Crystal Form of a Thianthrene Derivative (2018)
Journal Article

Thianthrenes have been nearly forgotten as phosphors in recent years, but are now coming back, showing their strong potential in luminescent applications. Here, we present a comprehensive photophysical study of a carbazolyl derivative of thianthrene... Read More about Observation of Dual Room Temperature Fluorescence-Phosphorescence in Air, in the Crystal Form of a Thianthrene Derivative.

Intermolecular Interactions in Molecular Crystals and Their Effect on Thermally Activated Delayed Fluorescence of Helicene-Based Emitters (2018)
Journal Article

Here, we discuss the influence of the crystal structure on the photophysical properties of two new TADF emitters containing a non-planar helical moiety. The presence of solvent in the crystal lattice of a diaza[5]helicene-based compound alters molecu... Read More about Intermolecular Interactions in Molecular Crystals and Their Effect on Thermally Activated Delayed Fluorescence of Helicene-Based Emitters.

The influence of molecular conformation on the photophysics of organic room temperature phosphorescent luminophores (2018)
Journal Article

A series of novel donor–acceptor–donor (D–A–D) compounds featuring dibenzothiophene (DBT) and phenothiazine (PTZ) units are presented. A different degree of steric hindrance between the donor and acceptor fragments is achieved by the systematic chang... Read More about The influence of molecular conformation on the photophysics of organic room temperature phosphorescent luminophores.

Thermally-Activated Delayed Fluorescence in Polymer-Small Molecule Exciplex Blends for Solution-Processed Organic Light-Emitting Diodes (2018)
Journal Article

The photophysics of an exciplex state, formed between a small molecule and a polymer, is investigated in this work. The results obtained with this blend show the strong potential of polymer-small molecule blends for triplet harvesting in organic ligh... Read More about Thermally-Activated Delayed Fluorescence in Polymer-Small Molecule Exciplex Blends for Solution-Processed Organic Light-Emitting Diodes.

1,2,4-Triazines in the Synthesis of Bipyridine Bisphenolate O^N^N^O Ligands and Their Highly Luminescent Tetradentate Pt(II) Complexes for Solution-Processable OLEDs (2018)
Journal Article

Easily accessible bis-1,2,4-triazines can be converted to corresponding pyridines by the Boger reaction, opening up convenient synthesis pathways to salen-type tetradentate dianionic ligands. The new ligands were used to prepare highly luminescent ON... Read More about 1,2,4-Triazines in the Synthesis of Bipyridine Bisphenolate O^N^N^O Ligands and Their Highly Luminescent Tetradentate Pt(II) Complexes for Solution-Processable OLEDs.

Multicolor Luminescence Switching and Controllable Thermally Activated Delayed Fluorescence Turn on/Turn off in Carbazole–Quinoxaline–Carbazole Triads (2018)
Journal Article

We report a series of thermally activated delayed fluorescence (TADF) molecules with mechanochromic luminescence properties and reversible TADF turn on/off properties in solid state that are induced by the transition between amorphous and crystalline... Read More about Multicolor Luminescence Switching and Controllable Thermally Activated Delayed Fluorescence Turn on/Turn off in Carbazole–Quinoxaline–Carbazole Triads.

Solution-Processable Thermally Activated Delayed Fluorescence White OLEDs Based on Dual-Emission Polymers with Tunable Emission Colors and Aggregation Enhanced Emission Properties (2017)
Journal Article

Thermally activated delayed fluorescence (TADF) white organic light-emitting diodes (WOLEDs) have drawn tremendous interest and have been extensively studied because of harvesting both triplet and singlet excitons without heavy metals. However, singl... Read More about Solution-Processable Thermally Activated Delayed Fluorescence White OLEDs Based on Dual-Emission Polymers with Tunable Emission Colors and Aggregation Enhanced Emission Properties.

Thermally Activated Delayed Fluorescence in Cu(I) Complexes Originating from Restricted Molecular Vibrations (2017)
Journal Article

The mechanism of thermally activated delayed fluorescence (TADF) in molecules in aggregated or condensed solid states has been rarely studied and is not well understood. Nevertheless, many applications of TADF emitters are strongly affected by their... Read More about Thermally Activated Delayed Fluorescence in Cu(I) Complexes Originating from Restricted Molecular Vibrations.

The Contributions of Molecular Vibrations and Higher Triplet Levels to the Intersystem Crossing Mechanism in Metal-Free Organic Emitters (2017)
Journal Article

Intense, simultaneous, room temperature phosphorescence (RTP) and thermally activated delayed fluorescence (TADF) is observed in a series of donor-acceptor-donor (D–A–D) molecules. This dual-luminescence is stronger in the “angular” isomers, compared... Read More about The Contributions of Molecular Vibrations and Higher Triplet Levels to the Intersystem Crossing Mechanism in Metal-Free Organic Emitters.

Regio- and conformational isomerization critical to design of efficient thermally-activated delayed fluorescence emitters (2017)
Journal Article

Regio- and conformational isomerization are fundamental in chemistry, with profound effects upon physical properties, however their role in excited state properties is less developed. Here two regioisomers of bis(10H-phenothiazin-10-yl)dibenzo[b,d]th... Read More about Regio- and conformational isomerization critical to design of efficient thermally-activated delayed fluorescence emitters.

Indirect consequences of exciplex states on the phosphorescence lifetime of phenazine-based 1,2,3-triazole luminescent probes (2016)
Journal Article

The optical properties of phenazine derivative probe solutions involving intersystem crossing from singlet to triplet states were investigated by time resolved spectroscopy. The room temperature phosphorescence emission presented different time respo... Read More about Indirect consequences of exciplex states on the phosphorescence lifetime of phenazine-based 1,2,3-triazole luminescent probes.

Pendant Homopolymer and Copolymers as Solution-Processable Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes (2016)
Journal Article

Materials that display thermally activated delayed fluorescence (TADF) have recently been identified as the third generation emitters for organic light-emitting diodes (OLEDs). However, there are only a few reported examples of polymeric TADF materia... Read More about Pendant Homopolymer and Copolymers as Solution-Processable Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes.

The Role of Local Triplet Excited States and D-A Relative Orientation in Thermally Activated Delayed Fluorescence: Photophysics and Devices (2016)
Journal Article

Here, a comprehensive photophysical investigation of a the emitter molecule DPTZ-DBTO2, showing thermally activated delayed fluorescence (TADF), with near-orthogonal electron donor (D) and acceptor (A) units is reported. It is shown that DPTZ-DBTO2 h... Read More about The Role of Local Triplet Excited States and D-A Relative Orientation in Thermally Activated Delayed Fluorescence: Photophysics and Devices.

Rational Design of TADF Polymers Using a Donor–Acceptor Monomer with Enhanced TADF Efficiency Induced by the Energy Alignment of Charge Transfer and Local Triplet Excited States (2016)
Journal Article

The photophysics of thermally activated delayed fluorescence (TADF) in phenothiazine-dibenzothiophene-S,S-dioxide (PTZ-DBTO2) molecule is investigated in detail. First, it is shown that the proximity of local triplet excited states (3LE), e.g., 3D or... Read More about Rational Design of TADF Polymers Using a Donor–Acceptor Monomer with Enhanced TADF Efficiency Induced by the Energy Alignment of Charge Transfer and Local Triplet Excited States.

The interplay of thermally activated delayed fluorescence (TADF) and room temperature organic phosphorescence in sterically-constrained donor–acceptor charge-transfer molecules (2016)
Journal Article

A series of phenothiazine–dibenzothiophene-S,S-dioxide charge-transfer molecules have been synthesized. Increasing steric restriction around the donor–acceptor bond significantly alters contributions from TADF and phosphorescence. Bulky substituents... Read More about The interplay of thermally activated delayed fluorescence (TADF) and room temperature organic phosphorescence in sterically-constrained donor–acceptor charge-transfer molecules.

Generating Light from Upper Excited Triplet States: A Contribution to the Indirect Singlet Yield of a Polymer OLED, Helping to Exceed the 25% Singlet Exciton Limit (2015)
Journal Article

The mechanisms by which light is generated in an organic light emitting diode have slowly been elucidated over the last ten years. The role of triplet annihilation has demonstrated how the “spin statistical limit” can be surpassed, but it cannot acco... Read More about Generating Light from Upper Excited Triplet States: A Contribution to the Indirect Singlet Yield of a Polymer OLED, Helping to Exceed the 25% Singlet Exciton Limit.

Kinetics of thermal-assisted delayed fluorescence in blue organic emitters with large singlet–triplet energy gap (2015)
Journal Article

The kinetics of thermally activated delayed fluorescence (TADF) is investigated in dilute solutions of organic materials with application in blue light-emitting diodes (OLEDs). A method to accurately determine the energy barrier (ΔEa) and the rate of... Read More about Kinetics of thermal-assisted delayed fluorescence in blue organic emitters with large singlet–triplet energy gap.

Inter/intrachain interactions behind the formation of charge transfer states in polyspirobifluorene: A case study for complex excited-state dynamics in different polarity index solvents (2015)
Journal Article

In this work, we demonstrate the complex excited-state nature of the conjugated polymer, polyspirobifluorene (PSBF), using steady-state and time-resolved spectroscopy techniques to understand the origin of excited charge transfer state (CT) formation... Read More about Inter/intrachain interactions behind the formation of charge transfer states in polyspirobifluorene: A case study for complex excited-state dynamics in different polarity index solvents.

Triplet Harvesting with 100% Efficiency by Way of Thermally Activated Delayed Fluorescence in Charge Transfer OLED Emitters. (2013)
Journal Article

Organic light-emitting diodes (OLEDs) have their performance limited by the number of emissive singlet states created upon charge recombination (25%). Recently, a novel strategy has been proposed, based on thermally activated up-conversion of triplet... Read More about Triplet Harvesting with 100% Efficiency by Way of Thermally Activated Delayed Fluorescence in Charge Transfer OLED Emitters..

Deep Blue Exciplex Organic Light-Emitting Diodes with Enhanced Efficiency; P-type or E-type Triplet Conversion to Singlet Excitons? (2013)
Journal Article

Simple trilayer, deep blue, fluorescent exciplex organic light-emitting diodes (OLEDs) are reported. These OLEDs emit from an exciplex state formed between the highest occupied molecular orbital (HOMO) of N,N′-bis(1-naphthyl)N,N′-diphenyl-1,1′-biphen... Read More about Deep Blue Exciplex Organic Light-Emitting Diodes with Enhanced Efficiency; P-type or E-type Triplet Conversion to Singlet Excitons?.

The contribution of triplet-triplet annihilation to the lifetime and efficiency of fluorescent polymer organic light emitting diodes (2011)
Journal Article

We demonstrate that the fast initial decay of a prototypical fluorescent polymer based organic light emitting diode device is related to the contribution that triplet-triplet annihilation makes to the device efficiency. We show that, during typical o... Read More about The contribution of triplet-triplet annihilation to the lifetime and efficiency of fluorescent polymer organic light emitting diodes.

Exploiting a Dual-Fluorescence Process in Fluorene-Dibenzothiophene-S,S-dioxide Co-Polymers to Give Efficient Single Polymer LEDs with Broadened Emission. (2009)
Journal Article

A description of the synthesis of random (9,9-dioctylfluorene-2,7-diyl)-dibenzothiophene-S,S-dioxide-3,7-diyl) co-polymers (p(F-S)x) by palladium- catalyzed Suzuki cross-coupling polymerization where the feed ration of the latter is varied from 2 to... Read More about Exploiting a Dual-Fluorescence Process in Fluorene-Dibenzothiophene-S,S-dioxide Co-Polymers to Give Efficient Single Polymer LEDs with Broadened Emission..

Exciton Diffusion in Polyfluorene Copolymer Thin Films: Kinetics, Energy Disorder and Thermally Assisted Hopping (2009)
Journal Article

A series of {(9,9-dioctylfluorene)(0.7-x)-(dibenzothiophene-S,S-dioxide)(0.3)-[4,7-b is(2-thienyl)-2,1,3-benzothiadiazole](x)} (PFS30-TBTx), where x represents the minor percentage of the red emitter 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole (TBT) ra... Read More about Exciton Diffusion in Polyfluorene Copolymer Thin Films: Kinetics, Energy Disorder and Thermally Assisted Hopping.

Enhanced triplet formation by twisted intramolecular charge-transfer excited states in conjugated oligomers and polymers. (2008)
Journal Article

The triplet yield and intersystem crossing rate of a set of conjugated oligomers and polymers that, in polar solvents, form a charge-transfer state with a twisted conformation has been investigated. It was observed that in these dibenzothiophene-fluo... Read More about Enhanced triplet formation by twisted intramolecular charge-transfer excited states in conjugated oligomers and polymers..

Intramolecular charge transfer assisted by conformational changes in the excited state of fluorene-dibenzothiophene-S,S-dioxide co-oligomers (2006)
Journal Article

The strong solvatochromism observed for two fluorene-dibenzothiophene-S,S-dioxide oligomers in polar solvents has been investigated using steady-state and time-resolved fluorescence techniques. A low-energy absorption band, attributed to a charge-tra... Read More about Intramolecular charge transfer assisted by conformational changes in the excited state of fluorene-dibenzothiophene-S,S-dioxide co-oligomers.

Fast and slow time regimes of fluorescence quenching in conjugated polyfluorene-fluorenone random copolymers: The role of exciton hopping and dexter transfer along the polymer backbone (2006)
Journal Article

The luminescence decay kinetics of polyfluorene copolymers containing fluorenone units randomly distributed along the polymer chain have been Studied by steady-state and time-resolved fluorescence techniques in toluene solution. The typical green emi... Read More about Fast and slow time regimes of fluorescence quenching in conjugated polyfluorene-fluorenone random copolymers: The role of exciton hopping and dexter transfer along the polymer backbone.

Bridged diiridium complexes for electrophosphorescent OLEDs : synthesis, X-ray crystal structures, photophysics, and devices. (2006)
Journal Article

Results are presented which challenge the accepted view that dinuclear transition metal–ligand complexes are unsuitable for organic light-emitting device (OLED) applications due to their low luminescence quantum efficiencies. We establish for the fir... Read More about Bridged diiridium complexes for electrophosphorescent OLEDs : synthesis, X-ray crystal structures, photophysics, and devices..

Oligo(fluorenyl) pyridine ligands and their tris-cyclometalated iridium(III) complexes: synthesis, photophysical properties and electrophosphorescent devices (2005)
Journal Article

The new extended tri- and penta-fluorenylpyridine ligands Fl(3)Py 2 and Fl(5)Py 3 and their tris-cyclometalated iridium(III) complexes Ir[Fl(3)Py](3) 5 and Ir[Fl(5)Py](3) 6 have been synthesised and their properties compared with the known iridium( I... Read More about Oligo(fluorenyl) pyridine ligands and their tris-cyclometalated iridium(III) complexes: synthesis, photophysical properties and electrophosphorescent devices.

An investigation into the excitation migration in polyfluorene solutions via temperature dependent fluorescence anisotropy. (2005)
Journal Article

Fluorescenceanisotropy of dilute polyfluorene polymer solutions has been used to show that two processes, exciton migration and conformational relaxation (twisting of part of the chain), occur within polyfluorene polymers of 20 or more repeat units.... Read More about An investigation into the excitation migration in polyfluorene solutions via temperature dependent fluorescence anisotropy..