Exciton-coupled charge-transfer dynamics in a porphyrin J-aggregate/TiO2 complex

Verma, Sandeep ; Ghosh, Amrita ; Das, Amitava ; Ghosh, Hirendra N. (2011) Exciton-coupled charge-transfer dynamics in a porphyrin J-aggregate/TiO2 complex Chemistry - A European Journal, 17 (12). pp. 3458-3464. ISSN 0947-6539

Full text not available from this repository.

Official URL: http://onlinelibrary.wiley.com/doi/10.1002/chem.20...

Related URL: http://dx.doi.org/10.1002/chem.201002537


Exciton-coupled charge-transfer (CT) dynamics in TiO2 nanoparticles (NP) sensitized with porphyrin J-aggregates has been studied by femtosecond time-resolved transient absorption spectroscopy. J-aggregates of 5,10,15-triphenyl-20-(3,4-dihydroxyphenyl) porphyrin (TPPcat) form CT complexes on TiO2 NP surfaces. Catechol-mediated strong CT coupling between J-aggregate and TiO2 NP facilitates interfacial exciton dissociation for electron injection into the conduction band of the TiO2 nanoparticle in pulse width limited time (<80 fs). Here, the electron-transfer (<80 fs) process dominates over the intrinsic exciton-relaxation process (J-aggregates: ca. 200 fs) on account of exciton-coupled CT interaction. The parent hole on J-aggregates is delocalized through J-aggregate excitonic coherence. As a result, holes immobilized on J-aggregates are spatially less accessible to electrons injected into TiO2, and thus the back electron transfer (BET) process is slower than that of the monomer/TiO2 system. The J-aggregate/porphyrin system shows exciton spectral and temporal properties for better charge separation in strongly coupled composite systems.

Item Type:Article
Source:Copyright of this article belongs to John Wiley and Sons.
Keywords:Aggregation; Charge Transfer; Frenkel Excitons; Porphyrins; Titania
ID Code:59967
Deposited On:08 Sep 2011 10:24
Last Modified:08 Sep 2011 10:24

Repository Staff Only: item control page