TY - JOUR
T1 - Mono- versus Bicyclic Carbene Metal Amide Photoemitters
T2 - Which Design Leads to the Best Performance?
AU - Chotard, Florian
AU - Sivchik, Vasily
AU - Linnolahti, Mikko
AU - Bochmann, Manfred
AU - Romanov, Alexander
PY - 2020/7/28
Y1 - 2020/7/28
N2 - New luminescent "carbene-metal-amide"(CMA) Cu, Ag, and Au complexes based on monocyclic (C6) or bicyclic six-ring (BIC6) cyclic (alkyl)(amino)carbene ligands illustrate the effects of LUMO energy stabilization, conformational flexibility, excited state energy, and geometry on the photoluminescent properties, leading to 100% luminescence quantum yields, short excited state lifetimes Cu > Au > Ag down to 0.5 μs, and high radiative rates of 106 s-1. Gold complexes with the BIC6 ligand exhibit exceptional photostability under hard and soft UV light compared with analogous complexes with C5 and C6 carbenes. Steady-state and time-resolved photoluminescence spectroscopy at 298 and 77 K enabled an estimate of the energy levels of the charge transfer (CT) and locally excited (LE) states with singlet and triplet character. A four-state model is applied to describe thermally activated delayed fluorescence (TADF) properties in CMA materials and correlates excited state lifetimes with the energy difference between LE and CT states.
AB - New luminescent "carbene-metal-amide"(CMA) Cu, Ag, and Au complexes based on monocyclic (C6) or bicyclic six-ring (BIC6) cyclic (alkyl)(amino)carbene ligands illustrate the effects of LUMO energy stabilization, conformational flexibility, excited state energy, and geometry on the photoluminescent properties, leading to 100% luminescence quantum yields, short excited state lifetimes Cu > Au > Ag down to 0.5 μs, and high radiative rates of 106 s-1. Gold complexes with the BIC6 ligand exhibit exceptional photostability under hard and soft UV light compared with analogous complexes with C5 and C6 carbenes. Steady-state and time-resolved photoluminescence spectroscopy at 298 and 77 K enabled an estimate of the energy levels of the charge transfer (CT) and locally excited (LE) states with singlet and triplet character. A four-state model is applied to describe thermally activated delayed fluorescence (TADF) properties in CMA materials and correlates excited state lifetimes with the energy difference between LE and CT states.
U2 - 10.1021/acs.chemmater.0c01769
DO - 10.1021/acs.chemmater.0c01769
M3 - Article
SN - 0897-4756
JO - Chemistry of Materials
JF - Chemistry of Materials
ER -