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Fluorescence as probe for transport and lateral order in vapor grown Langmuir‐Blodgett(LB) multilayer‐type single crystals of anthracene chromophores with fatty acid tails
Author(s) -
Weiß D.,
Kietzmann R.,
Storck W.,
Lehnert J.,
Willig F.
Publication year - 1991
Publication title -
makromolekulare chemie. macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 0258-0322
DOI - 10.1002/masy.19910460110
Subject(s) - anthracene , chromophore , langmuir–blodgett film , fluorescence , exciton , excited state , excimer , crystal (programming language) , photochemistry , chemistry , analytical chemistry (journal) , materials science , crystallography , optics , atomic physics , molecule , organic chemistry , physics , quantum mechanics , computer science , programming language
Abstract Fluorescence spectra of anthracene moieties with fatty acid tails attached at the 2‐position are reported for Langmuir‐Blodgett(LB)‐type multilayer configurations obtained as single crystals in the gas phase. These systems are considered the best ordered experimental model systems for chromophores with fatty acid tails arranged in the LB multilayer configuration. Closest agreement of the fluorescence spectrum with that of the unsubstituted anthracene crystal is found for the 4‐(2‐anthryl)‐1‐butanoic acid (2A4) crystal. Packing of the anthracene moieties is very similar in both crystals. Low‐temperature spectra (10 K) reveal strong broadening of the peaks due to spatial disorder in the 2A4 crystal. 7‐(2‐Anthryl)‐1‐heptanoic acid (2A7) crystals and even more so actual 2A7 LB multilayers have less structured fluorescence spectra that extend further to lower energies. Picosecond time resolved fluorescence decay curves show exciton transport and trapping in low energy traps. Compressed ground state pairs with excimer‐type spatial configurations are excited directly in the red (476 nm) to emit structureless excimer‐type fluorescence.