Triplet Sensitization in an Anionic Poly(phenyleneethynylene) Conjugated Polyelectrolyte by Cationic Iridium Complexes
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- 作者：Jarrett H. Vella ; Anand Parthasarathy ; Kirk S. Schanze
- 刊名：The Journal of Physical Chemistry A
- 出版年：2013
- 出版时间：August 22, 2013
- 年：2013
- 卷：117
- 期：33
- 页码：7818-7822
- 全文大小：282K
- 年卷期：v.117,no.33(August 22, 2013)
- ISSN：1520-5215
文摘
We describe a systematic study of triplet sensitization in a poly(phenyleneethynylene) conjugated polyelectrolyte (CPE) in methanol solution by using a series of three cationic iridium complexes with varying triplet energy. The cationic iridium complexes bind to the anionic CPE by ion-pairing, leading to singlet state quenching of the polymer, and allowing for efficient back-transfer of triplet excitation energy to the polymer. Efficient (amplified quenching) of the polymer鈥檚 fluorescence is observed for each iridium complex, with Stern鈥揤olmer quenching constants in excess of 105 M鈥?. Triplet sensitization is confirmed for two of the iridium complexes by monitoring the relative yield of the CPE triplet state by transient absorption spectroscopy. One of the iridium complexes does not sensitize the CPE triplet, and consideration of the energies of the three complexes allows us to bracket the triplet energy of the CPE within the range 1.95鈥?.26 eV.