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Aggregation of Zinc Protoporphyrin in Anodized Aluminum Oxide (AAO) Nanoporous Environments
Author(s) -
Lin JinShyong,
Chen YuChying,
Chen ChienChon,
Diau Eric WeiGuang,
Liu TzengFeng
Publication year - 2006
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200600022
Subject(s) - nanoporous , chemistry , anodizing , absorption spectroscopy , spectral line , absorption (acoustics) , visible spectrum , absorption band , oxide , analytical chemistry (journal) , photochemistry , aluminium , optoelectronics , optics , materials science , chromatography , composite material , organic chemistry , physics , astronomy
The aggregation behavior of zinc protoporphyrin (ZnPP) inside nanoporous environments of anodized aluminum oxide (AAO) has been investigated through observation of the variation of UV/visible absorption and emission spectra of the system. The Soret band in the absorption spectrum of ZnPP/AAO thin‐film samples becomes much broader than that observed for ZnPP/THF solutions, and the relative intensity of the Q band is distinctly enhanced for the former. The broad Soret band overlaps the enhanced Q band increasingly as the degree of aggregation increases with increasing duration of immersion, with initial concentration of ZnPP/THF solutions, or with decreasing pore size of AAO nanotubes. A strong excitonic coupling between the Soret and Q transition dipoles causes the absorption spectrum of the ZnPP/AAO system to cover the entire visible spectral region. Emission spectra of ZnPP/AAO samples in the steady state contain multiple resolvable components assigned to monomer, dimer and higher aggregates. The observed systematic variation of emission spectra of ZnPP/AAO samples is consistent with the observation in absorption spectra of the system and reflects the significance of aggregation of ZnPP in a specific nanoporous environment.