Luminescent Solar Concentrators Based on Renewable Polyester Matrices

This study reports for the first time the use of bio-based alternatives for PMMA as host matrix for luminescent solar concentrators (LSCs). Notably, two types of renewable polyesters were synthesized in varying molar ratios via a two-step melt-polycondensation reaction with dibutyl tin oxide as catalyst. The first is a homopolymer of diethyl 2,3:4,5-di-O-methylene galactarate (GxMe) and isosorbide (IGPn), and the second is a random copolymer of GxMe with 1,3-propanediol and dimethyl terephthalate (GTPn). The two polyesters were found to be optically transparent, totally amorphous with a Tg higher than 45 °C and temperature resistance comparable to PMMA. Lumogen Red (LR) and an aggregation-induced emission (AIE) fluorophore, TPETPAFN, were utilized as fluorophores and the derived thin polymer films (25 μm) were found highly homogeneous, especially for those prepared from GTPn, possibly due to the presence of compatibilizing terephthalate units in the matrix composition and the higher molecular weight. The spectroscopic characterization and the optical efficiency determination (ηopt) evidenced LSCs performances similar or superior to those collected from LR/PMMA thin films. Noteworthy, ηopt of 7.7 % and 7.1 % were recorded for the GTPn-based matrix containing LR and TPETPAFN, respectively, thus definitely supporting the bio-based polyesters as renewable and highly fluorophore-compatible matrices for high-performance LSCs.