Red-emitting tetraphenylethylene derivative with aggregation-induced enhanced emission for luminescent solar concentrators: A combined experimental and density functional theory study

This study examines the use of an aggregation-induced enhanced emission fluorophore (TPE-MRh) to prepare red-emitting luminescent solar concentrators (LSCs) based on poly(methyl methacrylate) (PMMA) and poly(cyclohexyl methacrylate) (PCMA). TPE-MRh is a tetraphenylethylene (TPE) derivative bearing two dimethylamino push groups and a 3-methyl-rhodanine pull moiety, with absorption maxima at around 500 nm and fluorescence peak at 700 nm that strongly increases in solid-state. TPE-MRh displays a typical crystallization-induced enhanced emission that has been rationalized by modeling the compound behavior in solution and solid-state via density functional theory calculations with the inclusion of the environment. TPE-MRh dispersed into 5 x 5 cm(2) polymer films with a thickness of 25 +/- 5 mu m has revealed a partial fluorescence quenching with fluorophore content. Quantum yields (QYs) below 10% for the 2 wt.% of doping have been addressed to the formation of less emissive micro-sized clusters of fluorophores. PMMA slabs with the same surface size but 3 mm of thickness and 200 ppm of TPE-MRh have provided QY of 36.5% thanks to the attenuation of the detrimental effects of fluorophore aggregation. This feature is reflected in the LSCs performance, with devices achieving the largest power collected by the photovoltaic cell.