The impact of the pi-electron conjugation length on the three-photon absorption cross section of fluorene derivatives.
The three-photon absorption cross sections of three different fluorene derivatives, with extended pi-electron conjugation lengths was experimentally measured and compared with shorter pi-electron conjugation length analogs. The effect of the conjugation length on the three-photon absorption cross section sigma(3) (') of this family of molecules has been elucidated. It is demonstrated that sigma(3) (') of the asymmetric compound D-pi-pi-pi-A is 6.6 times larger than its shorter configuration D-pi-A, while for the symmetric compounds D-pi-pi-pi-D and A-pi-pi-pi-A a two-fold enhancement was found relative to their shorter conjugation length analogs. Measurements of the three-photon excitation of these compounds in THF solution (10(-3)M) were accomplished with a tunable optical pulse generation pumped by a 25 ps Nd-YAG laser.
Cohanoschi
Ion
I
Department of Chemistry, University of Central Florida, Orlando, FL 32816-2366, USA.
Belfield
Kevin D
KD
Toro
Carlos
C
Yao
Sheng
S
Hernández
Florencio E
FE