Tetrathiafulvalene radical cation (TTF+.) Charge Transfer aggregates included in PMMA matrix, a Resonance Raman Study

TL;DR

This study investigates TTF+ radical cation aggregates in PMMA films using resonance Raman spectroscopy, revealing their structure and charge transfer properties through enhanced purification and spectroscopic analysis.

Contribution

The paper introduces a refined purification method for TTFClO4 salts and demonstrates their incorporation into PMMA films, enabling detailed spectroscopic analysis of TTF+ aggregates.

Findings

Identification of TTF+ radical cation dimers and aggregates

Observation of broad charge transfer bands in UV-VIS-NIR spectra

Resonance Raman spectroscopy confirms the nature of charge transfer species

Abstract

TTFClO4 salts were included in a PMMA matrix via solvent casting technique under vacuum, up to 72 hours of pumping. The synthesis of the salt, present in the literature was enriched with a further purification procedure, wich resulted important to obtain TTF+. radical cation aggregates. The thin films were characterized by low temperature UV-VIS-NIR absorption, and a multicomponent broad charge transfer band (CT) in the near infrared was found. Raman spectroscopy (RRS) in resonance with the CT transition allowed to study the origin of the CT absorption: the species present in the films were recognized as dimers and aggregates of TTF+. radical cation.