# Investigations on Organic Push–Pull Dyes for Luminescent Solar Concentrator Applications

## TL;DR

This paper investigates new organic dyes for use in solar concentrators, showing that one dye achieves high efficiency in converting light to energy.

## Contribution

The study introduces new push–pull dyes with high photoluminescence efficiency for luminescent solar concentrators.

## Key findings

- Compound 3 achieved a photoluminescence quantum yield of 81%.
- The highest light-to-energy conversion efficiency of 2.8% was observed with compound 3.
- Medium polarity and matrix stiffening significantly affect the dyes' photophysical behavior.

## Abstract

In recent years, the focus on luminescent solar concentrator
(LSC)
materials has been renewed thanks to their properties that support
their integration into PV technologies in buildings and in the urban
environment. In this work, three dyes bearing push–pull units
and presenting anthracene (compound 1) or 2,1,3-benzothiadiazole (BTZ-P6t,
compound 2, and TBTZ-P12t, compound 3) as the central chromophore
module are investigated as luminophores for the LSCs based on polyacrylate.
The optical and luminescence characterization of the dyes in solution
and in polyacrylate panels has been carried out to examine the impact
of medium polarity and stiffening on the photophysical behavior of
the dyes. The photoluminescence quantum yield (PLQY), decay times,
and radiative and nonradiative rate constants have been evaluated
together with the overlap integral to rationalize the reabsorption
phenomena. The photophysical parameters highlight that medium polarity
and matrix stiffening have an impact on the photoluminescence properties.
The evaluation of the photovoltaic performance, performed by placing
an edge of dye panels in contact with a silicon PV device, shows that
the panels act as LSCs. In particular, compound 3 exhibits the highest
value of PLQY (81%), resulting in the highest value of PV light-to-energy
conversion efficiencies (ηopt%, 2.8%). This study
proposes a thorough and correlated examination of the photophysical
characteristics of molecular systems when the media are switched from
solution to acrylate panels in order to rationalize the photovoltaic
performance of the prepared LSCs. Although the prepared dye-acrylate
panels fall outside accepted standard dimensions for LSC size, this
study is relevant to designing chromophore architecture for enhanced
efficiencies for LSCs.