TY  - JOUR
A1  - Wächtler, Maria
A1  - Kübel, Joachim
A1  - Barthelmes, Kevin
A1  - Winter, Andreas
A1  - Schmiedel, Alexander
A1  - Pascher, Torbjörn
A1  - Lambert, Christoph
A1  - Schubert, Ulrich S.
A1  - Dietzek, Benjamin
T1  - Energy transfer and formation of long-lived \(^3\)MLCT states in multimetallic complexes with extended highly conjugated bis-terpyridyl ligands
JF  - Physical Chemistry Chemical Physics
N2  - Multimetallic complexes with extended and highly conjugated bis-2,2':6',2''-terpyridyl bridging ligands, which present building blocks for coordination polymers, are investigated with respect to their ability to act as light-harvesting antennae. The investigated species combine Ru(II)- with Os(II)- and Fe(II)-terpyridyl chromophores, the latter acting as energy sinks. Due to the extended conjugated system the ligands are able to prolong the lifetime of the \(^3\)MLCT states compared to unsubstituted terpyridyl species by delocalization and energetic stabilization of the \(^3\)MLCT states. This concept is applied for the first time to Fe(II) terpyridyl species and results in an exceptionally long lifetime of 23 ps for the Fe(II) \(^3\)MLCT state. While partial energy (>80%) transfer is observed between the Ru(II) and Fe(II) centers with a time-constant of 15 ps, excitation energy is transferred completely from the Ru(II) to the Os(II) center within the first 200 fs after excitation.
KW  - polypyridyl complexes
KW  - bis-terpyridyl ligands
KW  - multimetallic complexes
KW  - metal-to-ligand charge transfer (MLCT)
KW  - RU-(II) complexes
KW  - Ru(II)–Fe(II)–Ru(II) complex
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-191041
VL  - 18
IS  - 4
ER  - 
TY  - JOUR
A1  - Ceyman, Harald
A1  - Rosspeintner, Arnulf
A1  - Schreck, Maximilian H.
A1  - Mützel, Carina
A1  - Stoy, Andreas
A1  - Vauthey, Eric
A1  - Lambert, Christoph
T1  - Cooperative enhancement versus additivity of two-photon-absorption cross sections in linear and branched squaraine superchromophores
JF  - Physical Chemistry Chemical Physics
N2  - The linear and nonlinear optical properties of a series of oligomeric squaraine dyes were investigated by one-photon absorption spectroscopy (1PA) and two-photon absorption (2PA) induced fluorescence spectroscopy. The superchromophores are based on two indolenine squaraine dyes with transoid (SQA) and cisoid configuration (SQB). Using these monomers, linear dimers and trimers as well as star-shaped trimers and hexamers with benzene or triphenylamine cores were synthesised and investigated. The red-shifted and intensified 1PA spectra of all superchromophores could well be explained by exciton coupling theory. In the linear chromophore arrangements we also found superradiance of fluorescence but not in the branched systems. Furthermore, the 2PA showed enhanced cross sections for the linear oligomers but only additivity for the branched systems. This emphasizes that the enhancement of the 2PA cross section in the linear arrangements is probably caused by orbital interactions of higher excited configurations.
KW  - 2-photon absorption
KW  - Vibronic contributions
KW  - One-photon
KW  - Molecules
KW  - Intensity
KW  - Multibranched structures
KW  - Optical properties
KW  - Dyes
KW  - Chromophores
KW  - Design
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-188299
VL  - 18
IS  - 24
ER  - 
TY  - JOUR
A1  - Harkin, David J.
A1  - Broch, Katharina
A1  - Schreck, Maximilian
A1  - Ceyman, Harald
A1  - Stoy, Andreas
A1  - Yong, Chaw-Keong
A1  - Nikolka, Mark
A1  - McCulloch, Ian
A1  - Stingelin, Natalie
A1  - Lambert, Christoph
A1  - Sirringhaus, Henning
T1  - Decoupling charge transport and electroluminescence in a high mobility polymer semiconductor
JF  - Advanced Materials
N2  - Fluorescence enhancement of a high-mobility polymer semiconductor is achieved via energy transfer to a higher fluorescence quantum yield squaraine dye molecule on 50 ps timescales. In organic light-emitting diodes, an order of magnitude enhancement of the external quantum efficiency is observed without reduction in the charge-carrier mobility resulting in radiances of up to 5 W str\(^{-1}\) m\(^{-2}\) at 800 nm.
KW  - Light-emitting diodes
KW  - Fiels-effect transistors
KW  - Energy transfer
KW  - Conjugated polymers
KW  - High performance
KW  - High efficiency
KW  - Perovskite
KW  - Amplification
KW  - Fluorescence
KW  - Emission
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187670
VL  - 28
IS  - 30
ER  -