Photophysical properties and energy transfer pathway of Er(III) complexes with Pt-porphyrin and terpyridine ligands.
The photophysical properties of Er(III) complexes coordinated with platinum[5,10,15-triphenyl-20-(4-carboxyphenyl)-porphyrin] (PtP) and terpyridine (tpy) ligands in organic solution were investigated. The Er(III) complex emitted sensitized near-IR (NIR) luminescence when the PtP ligands were excited under deoxygenated conditions. The quantum yield (PhiLn) of the sensitized luminescence was 0.015%, as evaluated from luminescence lifetime. The photophysical studies and theoretical calculations suggest that the Förster resonance mechanism is very suitable for the energy transfer from PtP to the Er(III) ion and occurred through the first triplet excited state of PtP. The 12.3% energy transfer from the triplet state to the 4F9/2 and 4I9/2 states of Er(III) occurred with a rate distribution of 3.36x10(5) and 6.67x10(4) s(-1), respectively. In addition, the observed triplet quantum yield of the PtP ligand in [Ln(PtP)3(tpy)] proved that the energy transfer from the singlet excited state of the PtP ligand to the Er(III) ion did not take place.
Nah
Min-Kook
MK
Center for Smart Light-Harvesting Materials and Department of Advanced Materials, Hannam University, Deajeon 306-791, Korea.
Oh
Jae Buem
JB
Kim
Hwan Kyu
HK
Choi
Kyong-Hoon
KH
Kim
Yong-Rok
YR
Kang
Jun-Gill
JG