%0 Journal Article
%A Furgal, Joseph
C.
%A Jung, Jae Hwan
%A Goodson, Theodore
%A Laine, Richard M.
%D 2013
%T Analyzing Structure–Photophysical Property
Relationships for Isolated T8, T10, and T12 Stilbenevinylsilsesquioxanes
%U https://acs.figshare.com/articles/journal_contribution/Analyzing_Structure_Photophysical_Property_Relationships_for_Isolated_T_sub_8_sub_T_sub_10_sub_and_T_sub_12_sub_Stilbenevinylsilsesquioxanes/2384524
%R 10.1021/ja4043092.s001
%2 https://acs.figshare.com/ndownloader/files/4024213
%K T 12 silsesquioxanes
%K show photophysical properties
%K absorption
%K chromophore
%K state energy transfer
%K cage
%K photophysical properties
%K T 12 StilbenevinylsilsesquioxanesSilsesquioxanes
%K photophysical study
%K fluorescence lifetime kinetics
%K SQ
%K solution photophysical properties
%X Silsesquioxanes (SQs) are of considerable
interest for hybrid electronic
and photonic materials. However, to date, their photophysical properties
have not been studied extensively, thus their potential remains conjecture.
Here we describe the first known efforts to map structure–photophysical
properties as a function of cage symmetry and size by comparing identically
functionalized systems. Our focus here is on the solution photophysical
properties of the title stilbenevinyl-SQs, which were characterized
using single photon absorption, two-photon absorption, fluorescence
emission, and fluorescence lifetime kinetics. We offer here the first
detailed photophysical study of the larger pure T10 and
T12 silsesquioxanes and show photophysical properties that
differ as a function of size, especially in their fluorescence behavior,
indicating that cage size and/or symmetry can strongly affect photophysical
properties. We also find that they offer excitation-dependent emission
(evidence of rare “red-edge” effects). The T10 stilbenevinyl-SQ offers up to a 10-fold increase in two-photon absorption
cross section per chromophore over a free chromophore, signifying
increased electronic coupling. The SQ cage compounds show “rise
times” of 700–1000 fs and low anisotropy (∼0.1)
in fluorescence lifetime kinetic studies. These results indicate excited
state energy transfer, unobserved for the free chromophores and unexpected
for systems with “inert” silica cores and for 3-D hybrid
molecular species. These findings provide the first detailed photophysical
study of chromophore-functionalized T10 and T12 silsesquioxanes and show that SQs may be considered a separate class
of compounds/materials with anticipated novel properties of value
in developing new components for electronic and photonic applications.
%I ACS Publications