# Interplay between Theory and Photophysical Characterization in Symmetric α-Substituted Thienyl BODIPY Molecule

## TL;DR

This study explores the photophysical properties of a BODIPY molecule, revealing how its two absorption bands behave differently under light.

## Contribution

The paper identifies the distinct nature of two absorption bands in a BODIPY molecule using ultrafast spectroscopy and theoretical calculations.

## Key findings

- Intramolecular energy transfer occurs when the high-energy absorption band is excited.
- The low-energy band enables efficient amplified spontaneous emission.
- DFT calculations explain the differing photophysical behaviors of the two bands.

## Abstract

4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based molecules have emerged as interesting materials for optoelectronic applications due to the possibility to easily fine-tune their photophysical and optical properties, dominated by two main absorption bands in the visible range. However, no studies have been reported on the nature of these spectral features. By means of ultrafast spectroscopy, we detect intramolecular energy transfer in a spin-coated film of di-thieno-phenyl BODIPY (DTPBDP) dispersed in a polystyrene matrix after pumping the high-energy absorption band. The same effect is not present upon pumping the lowest-energy band, which instead allows the achievement of efficient amplified spontaneous emission. Density functional calculations indicate the different nature of the two main absorption bands, explaining their different photophysical behavior.