The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform

Andrew P. Monkman - One of the best experts on this subject based on the ideXlab platform.

  • highly efficient solution processed single layer electrophosphorescent diodes and the effect of Molecular Dipole Moment
    Advanced Functional Materials, 2011
    Co-Authors: Hameed A Alattar, Gareth C. Griffiths, Tom N. Moore, Mustafa Tavasli, Mark A. Fox, Martin R. Bryce, Andrew P. Monkman
    Abstract:

    A new family of highly soluble electrophosphorescent dopants based on a series of tris-cyclometalated iridium(III) complexes ( 1 ‐ 4 ) of 2-(carbazol3-yl)-4/5-R-pyridine ligands with varying Molecular Dipole strengths have been synthesized. Highly effi cient, solution-processed, single-layer, electrophosphorescent diodes utilizing these complexes have been prepared and characterized. The high triplet energy poly(9-vinylcarbazole) PVK is used as a host polymer doped with 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4oxadiazole (PBD) for electron transport. Devices with a current effi ciency of 40 cd A − 1 corresponding to an EQE of 12% can thus be achieved. The effect of the type and position of the substituent (electron-withdrawing group (CF 3 ) and electron-donating group (OMe)) on the Molecular Dipole Moment of the complexes has been investigated. A correlation between the absorption strength of the singlet metal-to-ligand charge-transfer ( 1 MLCT) transition and the luminance spectral red shift as a function of solvent polarity is observed. The strength of the transition Dipole Moments for complexes 1‐4 has also been obtained from TD-DFT computations, and is found to be consistent with the observed Molecular Dipole Moments of these complexes. The relatively long lifetime of the excitons of the phosphorescence (microseconds) compared to the charge-carrier scattering time (less than nanoseconds), allows the transition Dipole Moment to be considered as a “quasi permanent Dipole”. Therefore, the carrier mobility is suffi ciently affected by the long-lived transition Dipole Moments of the phosphorescent molecules, which are randomly oriented in the medium. The dopant Dipoles cause positional and energetic disorder because of the locally modifi ed polarization energy. Furthermore, the electron-withdrawing group CF 3 induces strong carrier dispersion that enhances the electron mobility. Therefore, the strong transition Dipole Moment in complexes 3 and 4 perturbs both electron and hole mobilities, yielding a reduction in exciton formation and an increase in the device dark current, thereby decreasing the device effi ciency.

  • Highly Efficient, Solution‐Processed, Single‐Layer, Electrophosphorescent Diodes and the Effect of Molecular Dipole Moment
    Advanced Functional Materials, 2011
    Co-Authors: Hameed A. Al-attar, Gareth C. Griffiths, Tom N. Moore, Mustafa Tavasli, Mark A. Fox, Martin R. Bryce, Andrew P. Monkman
    Abstract:

    A new family of highly soluble electrophosphorescent dopants based on a series of tris-cyclometalated iridium(III) complexes ( 1 ‐ 4 ) of 2-(carbazol3-yl)-4/5-R-pyridine ligands with varying Molecular Dipole strengths have been synthesized. Highly effi cient, solution-processed, single-layer, electrophosphorescent diodes utilizing these complexes have been prepared and characterized. The high triplet energy poly(9-vinylcarbazole) PVK is used as a host polymer doped with 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4oxadiazole (PBD) for electron transport. Devices with a current effi ciency of 40 cd A − 1 corresponding to an EQE of 12% can thus be achieved. The effect of the type and position of the substituent (electron-withdrawing group (CF 3 ) and electron-donating group (OMe)) on the Molecular Dipole Moment of the complexes has been investigated. A correlation between the absorption strength of the singlet metal-to-ligand charge-transfer ( 1 MLCT) transition and the luminance spectral red shift as a function of solvent polarity is observed. The strength of the transition Dipole Moments for complexes 1‐4 has also been obtained from TD-DFT computations, and is found to be consistent with the observed Molecular Dipole Moments of these complexes. The relatively long lifetime of the excitons of the phosphorescence (microseconds) compared to the charge-carrier scattering time (less than nanoseconds), allows the transition Dipole Moment to be considered as a “quasi permanent Dipole”. Therefore, the carrier mobility is suffi ciently affected by the long-lived transition Dipole Moments of the phosphorescent molecules, which are randomly oriented in the medium. The dopant Dipoles cause positional and energetic disorder because of the locally modifi ed polarization energy. Furthermore, the electron-withdrawing group CF 3 induces strong carrier dispersion that enhances the electron mobility. Therefore, the strong transition Dipole Moment in complexes 3 and 4 perturbs both electron and hole mobilities, yielding a reduction in exciton formation and an increase in the device dark current, thereby decreasing the device effi ciency.

Mustafa Tavasli - One of the best experts on this subject based on the ideXlab platform.

  • highly efficient solution processed single layer electrophosphorescent diodes and the effect of Molecular Dipole Moment
    Advanced Functional Materials, 2011
    Co-Authors: Hameed A Alattar, Gareth C. Griffiths, Tom N. Moore, Mustafa Tavasli, Mark A. Fox, Martin R. Bryce, Andrew P. Monkman
    Abstract:

    A new family of highly soluble electrophosphorescent dopants based on a series of tris-cyclometalated iridium(III) complexes ( 1 ‐ 4 ) of 2-(carbazol3-yl)-4/5-R-pyridine ligands with varying Molecular Dipole strengths have been synthesized. Highly effi cient, solution-processed, single-layer, electrophosphorescent diodes utilizing these complexes have been prepared and characterized. The high triplet energy poly(9-vinylcarbazole) PVK is used as a host polymer doped with 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4oxadiazole (PBD) for electron transport. Devices with a current effi ciency of 40 cd A − 1 corresponding to an EQE of 12% can thus be achieved. The effect of the type and position of the substituent (electron-withdrawing group (CF 3 ) and electron-donating group (OMe)) on the Molecular Dipole Moment of the complexes has been investigated. A correlation between the absorption strength of the singlet metal-to-ligand charge-transfer ( 1 MLCT) transition and the luminance spectral red shift as a function of solvent polarity is observed. The strength of the transition Dipole Moments for complexes 1‐4 has also been obtained from TD-DFT computations, and is found to be consistent with the observed Molecular Dipole Moments of these complexes. The relatively long lifetime of the excitons of the phosphorescence (microseconds) compared to the charge-carrier scattering time (less than nanoseconds), allows the transition Dipole Moment to be considered as a “quasi permanent Dipole”. Therefore, the carrier mobility is suffi ciently affected by the long-lived transition Dipole Moments of the phosphorescent molecules, which are randomly oriented in the medium. The dopant Dipoles cause positional and energetic disorder because of the locally modifi ed polarization energy. Furthermore, the electron-withdrawing group CF 3 induces strong carrier dispersion that enhances the electron mobility. Therefore, the strong transition Dipole Moment in complexes 3 and 4 perturbs both electron and hole mobilities, yielding a reduction in exciton formation and an increase in the device dark current, thereby decreasing the device effi ciency.

  • Highly Efficient, Solution‐Processed, Single‐Layer, Electrophosphorescent Diodes and the Effect of Molecular Dipole Moment
    Advanced Functional Materials, 2011
    Co-Authors: Hameed A. Al-attar, Gareth C. Griffiths, Tom N. Moore, Mustafa Tavasli, Mark A. Fox, Martin R. Bryce, Andrew P. Monkman
    Abstract:

    A new family of highly soluble electrophosphorescent dopants based on a series of tris-cyclometalated iridium(III) complexes ( 1 ‐ 4 ) of 2-(carbazol3-yl)-4/5-R-pyridine ligands with varying Molecular Dipole strengths have been synthesized. Highly effi cient, solution-processed, single-layer, electrophosphorescent diodes utilizing these complexes have been prepared and characterized. The high triplet energy poly(9-vinylcarbazole) PVK is used as a host polymer doped with 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4oxadiazole (PBD) for electron transport. Devices with a current effi ciency of 40 cd A − 1 corresponding to an EQE of 12% can thus be achieved. The effect of the type and position of the substituent (electron-withdrawing group (CF 3 ) and electron-donating group (OMe)) on the Molecular Dipole Moment of the complexes has been investigated. A correlation between the absorption strength of the singlet metal-to-ligand charge-transfer ( 1 MLCT) transition and the luminance spectral red shift as a function of solvent polarity is observed. The strength of the transition Dipole Moments for complexes 1‐4 has also been obtained from TD-DFT computations, and is found to be consistent with the observed Molecular Dipole Moments of these complexes. The relatively long lifetime of the excitons of the phosphorescence (microseconds) compared to the charge-carrier scattering time (less than nanoseconds), allows the transition Dipole Moment to be considered as a “quasi permanent Dipole”. Therefore, the carrier mobility is suffi ciently affected by the long-lived transition Dipole Moments of the phosphorescent molecules, which are randomly oriented in the medium. The dopant Dipoles cause positional and energetic disorder because of the locally modifi ed polarization energy. Furthermore, the electron-withdrawing group CF 3 induces strong carrier dispersion that enhances the electron mobility. Therefore, the strong transition Dipole Moment in complexes 3 and 4 perturbs both electron and hole mobilities, yielding a reduction in exciton formation and an increase in the device dark current, thereby decreasing the device effi ciency.

Gareth C. Griffiths - One of the best experts on this subject based on the ideXlab platform.

  • highly efficient solution processed single layer electrophosphorescent diodes and the effect of Molecular Dipole Moment
    Advanced Functional Materials, 2011
    Co-Authors: Hameed A Alattar, Gareth C. Griffiths, Tom N. Moore, Mustafa Tavasli, Mark A. Fox, Martin R. Bryce, Andrew P. Monkman
    Abstract:

    A new family of highly soluble electrophosphorescent dopants based on a series of tris-cyclometalated iridium(III) complexes ( 1 ‐ 4 ) of 2-(carbazol3-yl)-4/5-R-pyridine ligands with varying Molecular Dipole strengths have been synthesized. Highly effi cient, solution-processed, single-layer, electrophosphorescent diodes utilizing these complexes have been prepared and characterized. The high triplet energy poly(9-vinylcarbazole) PVK is used as a host polymer doped with 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4oxadiazole (PBD) for electron transport. Devices with a current effi ciency of 40 cd A − 1 corresponding to an EQE of 12% can thus be achieved. The effect of the type and position of the substituent (electron-withdrawing group (CF 3 ) and electron-donating group (OMe)) on the Molecular Dipole Moment of the complexes has been investigated. A correlation between the absorption strength of the singlet metal-to-ligand charge-transfer ( 1 MLCT) transition and the luminance spectral red shift as a function of solvent polarity is observed. The strength of the transition Dipole Moments for complexes 1‐4 has also been obtained from TD-DFT computations, and is found to be consistent with the observed Molecular Dipole Moments of these complexes. The relatively long lifetime of the excitons of the phosphorescence (microseconds) compared to the charge-carrier scattering time (less than nanoseconds), allows the transition Dipole Moment to be considered as a “quasi permanent Dipole”. Therefore, the carrier mobility is suffi ciently affected by the long-lived transition Dipole Moments of the phosphorescent molecules, which are randomly oriented in the medium. The dopant Dipoles cause positional and energetic disorder because of the locally modifi ed polarization energy. Furthermore, the electron-withdrawing group CF 3 induces strong carrier dispersion that enhances the electron mobility. Therefore, the strong transition Dipole Moment in complexes 3 and 4 perturbs both electron and hole mobilities, yielding a reduction in exciton formation and an increase in the device dark current, thereby decreasing the device effi ciency.

  • Highly Efficient, Solution‐Processed, Single‐Layer, Electrophosphorescent Diodes and the Effect of Molecular Dipole Moment
    Advanced Functional Materials, 2011
    Co-Authors: Hameed A. Al-attar, Gareth C. Griffiths, Tom N. Moore, Mustafa Tavasli, Mark A. Fox, Martin R. Bryce, Andrew P. Monkman
    Abstract:

    A new family of highly soluble electrophosphorescent dopants based on a series of tris-cyclometalated iridium(III) complexes ( 1 ‐ 4 ) of 2-(carbazol3-yl)-4/5-R-pyridine ligands with varying Molecular Dipole strengths have been synthesized. Highly effi cient, solution-processed, single-layer, electrophosphorescent diodes utilizing these complexes have been prepared and characterized. The high triplet energy poly(9-vinylcarbazole) PVK is used as a host polymer doped with 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4oxadiazole (PBD) for electron transport. Devices with a current effi ciency of 40 cd A − 1 corresponding to an EQE of 12% can thus be achieved. The effect of the type and position of the substituent (electron-withdrawing group (CF 3 ) and electron-donating group (OMe)) on the Molecular Dipole Moment of the complexes has been investigated. A correlation between the absorption strength of the singlet metal-to-ligand charge-transfer ( 1 MLCT) transition and the luminance spectral red shift as a function of solvent polarity is observed. The strength of the transition Dipole Moments for complexes 1‐4 has also been obtained from TD-DFT computations, and is found to be consistent with the observed Molecular Dipole Moments of these complexes. The relatively long lifetime of the excitons of the phosphorescence (microseconds) compared to the charge-carrier scattering time (less than nanoseconds), allows the transition Dipole Moment to be considered as a “quasi permanent Dipole”. Therefore, the carrier mobility is suffi ciently affected by the long-lived transition Dipole Moments of the phosphorescent molecules, which are randomly oriented in the medium. The dopant Dipoles cause positional and energetic disorder because of the locally modifi ed polarization energy. Furthermore, the electron-withdrawing group CF 3 induces strong carrier dispersion that enhances the electron mobility. Therefore, the strong transition Dipole Moment in complexes 3 and 4 perturbs both electron and hole mobilities, yielding a reduction in exciton formation and an increase in the device dark current, thereby decreasing the device effi ciency.

Martin R. Bryce - One of the best experts on this subject based on the ideXlab platform.

  • highly efficient solution processed single layer electrophosphorescent diodes and the effect of Molecular Dipole Moment
    Advanced Functional Materials, 2011
    Co-Authors: Hameed A Alattar, Gareth C. Griffiths, Tom N. Moore, Mustafa Tavasli, Mark A. Fox, Martin R. Bryce, Andrew P. Monkman
    Abstract:

    A new family of highly soluble electrophosphorescent dopants based on a series of tris-cyclometalated iridium(III) complexes ( 1 ‐ 4 ) of 2-(carbazol3-yl)-4/5-R-pyridine ligands with varying Molecular Dipole strengths have been synthesized. Highly effi cient, solution-processed, single-layer, electrophosphorescent diodes utilizing these complexes have been prepared and characterized. The high triplet energy poly(9-vinylcarbazole) PVK is used as a host polymer doped with 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4oxadiazole (PBD) for electron transport. Devices with a current effi ciency of 40 cd A − 1 corresponding to an EQE of 12% can thus be achieved. The effect of the type and position of the substituent (electron-withdrawing group (CF 3 ) and electron-donating group (OMe)) on the Molecular Dipole Moment of the complexes has been investigated. A correlation between the absorption strength of the singlet metal-to-ligand charge-transfer ( 1 MLCT) transition and the luminance spectral red shift as a function of solvent polarity is observed. The strength of the transition Dipole Moments for complexes 1‐4 has also been obtained from TD-DFT computations, and is found to be consistent with the observed Molecular Dipole Moments of these complexes. The relatively long lifetime of the excitons of the phosphorescence (microseconds) compared to the charge-carrier scattering time (less than nanoseconds), allows the transition Dipole Moment to be considered as a “quasi permanent Dipole”. Therefore, the carrier mobility is suffi ciently affected by the long-lived transition Dipole Moments of the phosphorescent molecules, which are randomly oriented in the medium. The dopant Dipoles cause positional and energetic disorder because of the locally modifi ed polarization energy. Furthermore, the electron-withdrawing group CF 3 induces strong carrier dispersion that enhances the electron mobility. Therefore, the strong transition Dipole Moment in complexes 3 and 4 perturbs both electron and hole mobilities, yielding a reduction in exciton formation and an increase in the device dark current, thereby decreasing the device effi ciency.

  • Highly Efficient, Solution‐Processed, Single‐Layer, Electrophosphorescent Diodes and the Effect of Molecular Dipole Moment
    Advanced Functional Materials, 2011
    Co-Authors: Hameed A. Al-attar, Gareth C. Griffiths, Tom N. Moore, Mustafa Tavasli, Mark A. Fox, Martin R. Bryce, Andrew P. Monkman
    Abstract:

    A new family of highly soluble electrophosphorescent dopants based on a series of tris-cyclometalated iridium(III) complexes ( 1 ‐ 4 ) of 2-(carbazol3-yl)-4/5-R-pyridine ligands with varying Molecular Dipole strengths have been synthesized. Highly effi cient, solution-processed, single-layer, electrophosphorescent diodes utilizing these complexes have been prepared and characterized. The high triplet energy poly(9-vinylcarbazole) PVK is used as a host polymer doped with 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4oxadiazole (PBD) for electron transport. Devices with a current effi ciency of 40 cd A − 1 corresponding to an EQE of 12% can thus be achieved. The effect of the type and position of the substituent (electron-withdrawing group (CF 3 ) and electron-donating group (OMe)) on the Molecular Dipole Moment of the complexes has been investigated. A correlation between the absorption strength of the singlet metal-to-ligand charge-transfer ( 1 MLCT) transition and the luminance spectral red shift as a function of solvent polarity is observed. The strength of the transition Dipole Moments for complexes 1‐4 has also been obtained from TD-DFT computations, and is found to be consistent with the observed Molecular Dipole Moments of these complexes. The relatively long lifetime of the excitons of the phosphorescence (microseconds) compared to the charge-carrier scattering time (less than nanoseconds), allows the transition Dipole Moment to be considered as a “quasi permanent Dipole”. Therefore, the carrier mobility is suffi ciently affected by the long-lived transition Dipole Moments of the phosphorescent molecules, which are randomly oriented in the medium. The dopant Dipoles cause positional and energetic disorder because of the locally modifi ed polarization energy. Furthermore, the electron-withdrawing group CF 3 induces strong carrier dispersion that enhances the electron mobility. Therefore, the strong transition Dipole Moment in complexes 3 and 4 perturbs both electron and hole mobilities, yielding a reduction in exciton formation and an increase in the device dark current, thereby decreasing the device effi ciency.

Mark A. Fox - One of the best experts on this subject based on the ideXlab platform.

  • highly efficient solution processed single layer electrophosphorescent diodes and the effect of Molecular Dipole Moment
    Advanced Functional Materials, 2011
    Co-Authors: Hameed A Alattar, Gareth C. Griffiths, Tom N. Moore, Mustafa Tavasli, Mark A. Fox, Martin R. Bryce, Andrew P. Monkman
    Abstract:

    A new family of highly soluble electrophosphorescent dopants based on a series of tris-cyclometalated iridium(III) complexes ( 1 ‐ 4 ) of 2-(carbazol3-yl)-4/5-R-pyridine ligands with varying Molecular Dipole strengths have been synthesized. Highly effi cient, solution-processed, single-layer, electrophosphorescent diodes utilizing these complexes have been prepared and characterized. The high triplet energy poly(9-vinylcarbazole) PVK is used as a host polymer doped with 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4oxadiazole (PBD) for electron transport. Devices with a current effi ciency of 40 cd A − 1 corresponding to an EQE of 12% can thus be achieved. The effect of the type and position of the substituent (electron-withdrawing group (CF 3 ) and electron-donating group (OMe)) on the Molecular Dipole Moment of the complexes has been investigated. A correlation between the absorption strength of the singlet metal-to-ligand charge-transfer ( 1 MLCT) transition and the luminance spectral red shift as a function of solvent polarity is observed. The strength of the transition Dipole Moments for complexes 1‐4 has also been obtained from TD-DFT computations, and is found to be consistent with the observed Molecular Dipole Moments of these complexes. The relatively long lifetime of the excitons of the phosphorescence (microseconds) compared to the charge-carrier scattering time (less than nanoseconds), allows the transition Dipole Moment to be considered as a “quasi permanent Dipole”. Therefore, the carrier mobility is suffi ciently affected by the long-lived transition Dipole Moments of the phosphorescent molecules, which are randomly oriented in the medium. The dopant Dipoles cause positional and energetic disorder because of the locally modifi ed polarization energy. Furthermore, the electron-withdrawing group CF 3 induces strong carrier dispersion that enhances the electron mobility. Therefore, the strong transition Dipole Moment in complexes 3 and 4 perturbs both electron and hole mobilities, yielding a reduction in exciton formation and an increase in the device dark current, thereby decreasing the device effi ciency.

  • Highly Efficient, Solution‐Processed, Single‐Layer, Electrophosphorescent Diodes and the Effect of Molecular Dipole Moment
    Advanced Functional Materials, 2011
    Co-Authors: Hameed A. Al-attar, Gareth C. Griffiths, Tom N. Moore, Mustafa Tavasli, Mark A. Fox, Martin R. Bryce, Andrew P. Monkman
    Abstract:

    A new family of highly soluble electrophosphorescent dopants based on a series of tris-cyclometalated iridium(III) complexes ( 1 ‐ 4 ) of 2-(carbazol3-yl)-4/5-R-pyridine ligands with varying Molecular Dipole strengths have been synthesized. Highly effi cient, solution-processed, single-layer, electrophosphorescent diodes utilizing these complexes have been prepared and characterized. The high triplet energy poly(9-vinylcarbazole) PVK is used as a host polymer doped with 2-(4-biphenylyl)-5-(4-tert-butyl-phenyl)-1,3,4oxadiazole (PBD) for electron transport. Devices with a current effi ciency of 40 cd A − 1 corresponding to an EQE of 12% can thus be achieved. The effect of the type and position of the substituent (electron-withdrawing group (CF 3 ) and electron-donating group (OMe)) on the Molecular Dipole Moment of the complexes has been investigated. A correlation between the absorption strength of the singlet metal-to-ligand charge-transfer ( 1 MLCT) transition and the luminance spectral red shift as a function of solvent polarity is observed. The strength of the transition Dipole Moments for complexes 1‐4 has also been obtained from TD-DFT computations, and is found to be consistent with the observed Molecular Dipole Moments of these complexes. The relatively long lifetime of the excitons of the phosphorescence (microseconds) compared to the charge-carrier scattering time (less than nanoseconds), allows the transition Dipole Moment to be considered as a “quasi permanent Dipole”. Therefore, the carrier mobility is suffi ciently affected by the long-lived transition Dipole Moments of the phosphorescent molecules, which are randomly oriented in the medium. The dopant Dipoles cause positional and energetic disorder because of the locally modifi ed polarization energy. Furthermore, the electron-withdrawing group CF 3 induces strong carrier dispersion that enhances the electron mobility. Therefore, the strong transition Dipole Moment in complexes 3 and 4 perturbs both electron and hole mobilities, yielding a reduction in exciton formation and an increase in the device dark current, thereby decreasing the device effi ciency.