New perylene dyes for LSC

The rapid world population growth and the ever-decreasing amount of fossil fuels have boosted enormous interest in the solar cell technology and are leading to the search for alternative energy sources, to meet the increasing energy demand. Luminescent organic fluorophores play an important role in the Luminescent Solar Concentrator (LSC) technology, which consists of a transparent slab (generally made of PMMA) containing a highly luminescent dye that absorbs a portion of sunlight and re-emits it. This light is concentrated at the edges through total internal reflection [1]. Among the wide variety of fluorophores employed for LSCs, dyes based on perylene diimides (PDI) represent a valid choice thanks to the ease of functionalization and the interesting optical properties, such as the high fluorescence quantum yield [2]. Here we present two new perylene diimides 1 and 2 (Figure). In particular, compound 2 was incorporated into two polymeric matrices: the first one being a conventional PMMA matrix, whereas the second one a Diels-Alder matrix, i.e. a novel matrix with thermo-reversible properties, containing furan rings suitable to covalently link the fluorophores. The optical properties of the devices were tested, and their efficiencies are comparable to those reported in the literature using commercial perylene dyes, such as Lumogen F Red 305, characterized by a similar molecular structure but unable to be covalently linked to the polymeric matrix. Therefore, compound 2 is a promising luminophore candidate for light harvesting applications, such as luminescent solar concentrators. [1] M.G. Debije et al. Adv. Energ. Mat., 2 (2012) 12-35 [2] D. Pintossi et al. J. Mater. Chem. A, 5, (2017) 9067-9075