Self-assembly of monomethyncyanine and merocyanine dyes: impact of the intramolecular dipole and substrate used

Mykola Sieryk,Oleg Dimitriev

doi:10.15761/fnn.1000170

Abstract

Self-assembly of monomethyncyanine and merocyanine dyes: impact of the intramolecular dipole and substrate used

Highlights

The development of electronic devices based on organic materials, i.e., small molecules or polymers with conjugated bonds, whose films have semiconducting properties, demonstrates continuous adaptation of new materials that provide various advantages such as cheapness, plasticity, flexibility, ease of chemical modification, production on large scale from solutions, etc. [1,2,3,4,5,6]
The optical properties of molecular films to some extent correlate with the structure of molecular aggregates that are formed as a result of intermolecular interaction, and the analysis of the aggregate structure through optical features is still largely based on the Kasha model, which was developed half a century ago [14,15]
We compare self-assembly of molecular aggregates of two different compounds representing monomethyncyanine and merocyanine dyes, respectively (Figure 1), which differ by location, size, and orientation of their dipole moments arisen due to intramolecular polarity, in respect to the molecular plane, and which are able to undergo intramolecular conformational changes [19,20]

Summary

Introduction

The development of electronic devices based on organic materials, i.e., small molecules or polymers with conjugated bonds, whose films have semiconducting properties, demonstrates continuous adaptation of new materials that provide various advantages such as cheapness, plasticity, flexibility, ease of chemical modification, production on large scale from solutions, etc. [1,2,3,4,5,6]. Molecular simulation showed that the dimer structure of H-type should be in the form of a stack, with antiparallel dipole orientation of the adjacent molecules (Figure 5a), while in J-aggregate the molecules are located ‘head-to-tail’ where the dipoles are parallel (Figure 5b). Due to the relatively weak molecular dipole, the intermolecular aggregation here is weak and the influence of the metal substrate through image forces [21] dominates, which promotes more flat conformation of the molecules (Figure 6).

Results

Conclusion