Concentration dependent evolution of aggregates formed by chlorinated and non-chlorinated perylene tetracarboxylic acid esters in pure spin-coated films and in a PMMA matrix
Emilia Piosik , Anna Synak , Joanna Paluszkiewicz , Tomasz Martyński
AbstractMolecular organization of non-chlorinated (Pn) and chlorinated (PCln) esters of perylene tetracarboxylic acid with four lateral alkyl chains composed of n carbon atoms (n = 4, 10) in spin-coated films has been studied. The Pn dyes have shown a strong tendency for aggregation in the ground and excited state, which can be limited by long alkyl chains. Fluorescence quantum yield (FQY) of their film does not exceed the value of 0.04 and is far below that of the strongly diluted toluene solution (0.87). Chlorine atoms attached in the bay positions of the PCln dyes caused twisting of the perylene skeleton, which resulted in longer intermolecular distances and weaker interactions between molecules in films. In this way, an aggregation process was reduced and the role of the alkyl chains length as a steric hindrance was suppressed. However, FQY of the PCln films is below 0.24, because of its low value measured for the monomeric form in diluted solution (0.35). Furthermore, the concentration effect of the Pn and PCln dyes dispersed in poly (methyl methacrylate) (PMMA) on types of aggregates formed by them and on FQY value has been studied. FQY of the Pn derivatives increased with the drop of their concentration in PMMA up to the values of 0.59 and 0.69 for the dyes with shorter and longer alkyl chains, respectively. This makes them promising materials for application in organic light emitting diodes. In turn, FQY of the PCln derivatives in PMMA matrix was in the range of 0.17–0.37 and does not change in a regular way with dyes concentration.
|Journal series||Journal of Luminescence, ISSN 0022-2313, (A 35 pkt)|
|Publication size in sheets||0.65|
|Keywords in English||perylene dyes, ultra-thin films, time-resolved emission spectra, fluorescence lifetime, fluorescence quantum yield, organic light emitting diodes|
|ASJC Classification||; ; ; ;|
|Score||= 35.0, 24-07-2019, ArticleFromJournal|
|Publication indicators||: 2016 = 1.14; : 2017 = 2.732 (2) - 2017=2.577 (5)|
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