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Dr Fernando Dias' Outputs (122)

Indirect consequences of exciplex states on the phosphorescence lifetime of phenazine-based 1,2,3-triazole luminescent probes (2016)
Journal Article
Costa, B. B. A., Jardim, G. A. M., Santos, P. L., Calado, H. D. R., Monkman, A. P., Dias, F. B., da Silva Júnior, E. N., & Cury, L. (2017). Indirect consequences of exciplex states on the phosphorescence lifetime of phenazine-based 1,2,3-triazole luminescent probes. Physical Chemistry Chemical Physics, 19(5), 3473-3479. https://doi.org/10.1039/c6cp06134f

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
Ren, Z., Nobuyasu, R. S., Dias, F. B., Monkman, A. P., Yan, S., & Bryce, M. R. (2016). Pendant Homopolymer and Copolymers as Solution-Processable Thermally Activated Delayed Fluorescence Materials for Organic Light-Emitting Diodes. Macromolecules, 49(15), 5452-5460. https://doi.org/10.1021/acs.macromol.6b01216

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.

Investigation of the Mechanisms Giving Rise to TADF in Exciplex States (2016)
Journal Article
dos Santos, P. L., Dias, F. B., & Monkman, A. P. (2016). Investigation of the Mechanisms Giving Rise to TADF in Exciplex States. Journal of Physical Chemistry C, 120(32), 18259-18267. https://doi.org/10.1021/acs.jpcc.6b05198

The donor–acceptor systems studied in this work have been demonstrated to show strong exciplex formation by their red-shifted PL emission when compared with the individual donor and acceptor molecules, and all give rise to delayed fluorescence. In al... Read More about Investigation of the Mechanisms Giving Rise to TADF in Exciplex States.

The Role of Local Triplet Excited States and D-A Relative Orientation in Thermally Activated Delayed Fluorescence: Photophysics and Devices (2016)
Journal Article
Dias, F., Santos, J., Graves, D., Data, P., Nobuyasu, R., Fox, M., …Monkman, A. (2016). The Role of Local Triplet Excited States and D-A Relative Orientation in Thermally Activated Delayed Fluorescence: Photophysics and Devices. Advanced Science, 3(12), Article 1600080. https://doi.org/10.1002/advs.201600080

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
Nobuyasu, R. S., Ren, Z., Griffiths, G. C., Batsanov, A. S., Data, P., Yan, S., …Dias, F. B. (2016). 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. Advanced Optical Materials, 4(4), 597-607. https://doi.org/10.1002/adom.201500689

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
Ward, J. S., Nobuyasu, R. S., Batsanov, A. S., Data, P., Monkman, A. P., Dias, F. B., & Bryce, M. R. (2016). The interplay of thermally activated delayed fluorescence (TADF) and room temperature organic phosphorescence in sterically-constrained donor–acceptor charge-transfer molecules. Chemical Communications, 52(12), 2612-2615. https://doi.org/10.1039/c5cc09645f

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.

Engineering the singlet–triplet energy splitting in a TADF molecule (2016)
Journal Article
Santos, P. L., Ward, J. S., Data, P., Batsanov, A. S., Bryce, M. R., Dias, F. B., & Monkman, A. P. (2016). Engineering the singlet–triplet energy splitting in a TADF molecule. Journal of Materials Chemistry C Materials for optical and electronic devices, 4(17), 3815-3824. https://doi.org/10.1039/c5tc03849a

The key to engineering an efficient TADF emitter is to achieve a small energy splitting between a pair of molecular singlet and triplet states. This work makes important contributions towards achieving this goal. By studying the new TADF emitter 2,7-... Read More about Engineering the singlet–triplet energy splitting in a TADF molecule.

Synthesis and investigation of intra-molecular charge transfer state properties of novel donor-acceptor-donor pyridine derivatives: the effects of temperature and environment on molecular configurations and the origin of delayed fluorescence (2015)
Journal Article
Aydemir, M., Haykir, G., Turksoy, F., Gumus, S., Dias, F., & Monkman, A. (2015). Synthesis and investigation of intra-molecular charge transfer state properties of novel donor-acceptor-donor pyridine derivatives: the effects of temperature and environment on molecular configurations and the origin of delayed fluorescence. Physical Chemistry Chemical Physics, 17(38), 25572-25582. https://doi.org/10.1039/c5cp03937a

A novel series of donor-acceptor-donor (D-A-D) structured pyridine derivatives were synthesised and detailed photo-physical investigations were made using mainly steady-state and time-resolved spectroscopy techniques at varying temperatures. The inve... Read More about Synthesis and investigation of intra-molecular charge transfer state properties of novel donor-acceptor-donor pyridine derivatives: the effects of temperature and environment on molecular configurations and the origin of delayed fluorescence.

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
Jankus, V., Aydemir, M., Dias, F. B., & Monkman, A. P. (2016). 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. Advanced Science, 3(1), Article 1500221. https://doi.org/10.1002/advs.201500221

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.

Spectroscopic studies of different poly3hexylthiophene chain environments in a polyfluorene matrix (2015)
Journal Article
Santos, P. L., Cury, L. A., Dias, F. B., & Monkman, A. P. (2016). Spectroscopic studies of different poly3hexylthiophene chain environments in a polyfluorene matrix. Journal of Luminescence, 172, 118-123. https://doi.org/10.1016/j.jlumin.2015.11.045

Optical properties of blends made of poly(9,9-dioctyl-fluorene-2,7-diyl) (PFO) and poly(3-hexylthiophene-2,5-diyl) (P3HT) were investigated and compared to those of poly(9,9-dioctylfluorene-alt-bithiophene) (F8T2) by steady state optical spectroscopy... Read More about Spectroscopic studies of different poly3hexylthiophene chain environments in a polyfluorene matrix.

Kinetics of thermal-assisted delayed fluorescence in blue organic emitters with large singlet–triplet energy gap (2015)
Journal Article
Dias, F. B. (2015). Kinetics of thermal-assisted delayed fluorescence in blue organic emitters with large singlet–triplet energy gap. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 373(2044), Article 20140447. https://doi.org/10.1098/rsta.2014.0447

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
Aydemir, M., Jankus, V., Dias, F. B., & Monkman, A. P. (2015). 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. Journal of Physical Chemistry C, 119(11), 5855-5863. https://doi.org/10.1021/jp512467g

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.

Highly Efficient TADF OLEDs: How the Emitter–Host Interaction Controls Both the Excited State Species and Electrical Properties of the Devices to Achieve Near 100% Triplet Harvesting and High Efficiency (2014)
Journal Article
Jankus, V., Data, P., Graves, D., McGuinness, C., Santos, J., Bryce, M., …Monkman, A. (2014). Highly Efficient TADF OLEDs: How the Emitter–Host Interaction Controls Both the Excited State Species and Electrical Properties of the Devices to Achieve Near 100% Triplet Harvesting and High Efficiency. Advanced Functional Materials, 24(39), 6178-6186. https://doi.org/10.1002/adfm.201400948

New emitters that can harvest both singlet and triplet excited states to give 100% internal conversion of charge into light, are required to replace Ir based phosphors in organic light emitting diodes (OLEDs). Molecules that have a charge transfer (C... Read More about Highly Efficient TADF OLEDs: How the Emitter–Host Interaction Controls Both the Excited State Species and Electrical Properties of the Devices to Achieve Near 100% Triplet Harvesting and High Efficiency.

Ultrafast Dynamics and Computational Studies on Diaminodicyanoquinodimethanes (DADQs) (2014)
Journal Article
Szablewski, M., Fox, M., Dias, F., Namih, H., Snedden, E., King, S., …Pålsson, L. (2014). Ultrafast Dynamics and Computational Studies on Diaminodicyanoquinodimethanes (DADQs). Journal of Physical Chemistry B (Soft Condensed Matter and Biophysical Chemistry), 118(24), 6815-6828. https://doi.org/10.1021/jp411358d

Three diaminodicyanoquinodimethanes, 4-(R1R2C)-1-[(NC)2C]-C6H4 (R1,R2 = H2N, 1; R1 = 3,5-Me2-4-OCH4H6N–, R2 = H2N, 2; R1 = 3,5-Me2-4-OCH4H6N–, R2 = 4-Me-C5H9N, 3), were investigated using carbon-13 NMR, steady-state, and ultrafast transient absorptio... Read More about Ultrafast Dynamics and Computational Studies on Diaminodicyanoquinodimethanes (DADQs).

Triplet Harvesting with 100% Efficiency by Way of Thermally Activated Delayed Fluorescence in Charge Transfer OLED Emitters. (2013)
Journal Article
Dias, F., Bourdakos, K., Jankus, V., Moss, K., Kamtekar, K., Bhalla, V., …Monkman, A. (2013). Triplet Harvesting with 100% Efficiency by Way of Thermally Activated Delayed Fluorescence in Charge Transfer OLED Emitters. Advanced Materials, 25(27), 3707-3714. https://doi.org/10.1002/adma.201300753

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..