Visible-light excitable, highly transparent and luminescent films with an ultrahigh loading of a europium(III) complex

Visible light as an excitation source is much more accessible than ultraviolet light, but the synthesis of lanthanide complex (LnC) films with visible-light excitation and high photoluminescence quantum yield (PLQY) is still a challenge. We report herein a visible light excitable and highly luminescent film by incorporation of a europium(III) (Eu3+) tetrakis(β-diketonate) complex with tetraphenylphosphonium as a counterion into a polymethyl methacrylate (PMMA) matrix. Excellent compatibility between the complex and PMMA was observed, resulting in the PMMA film with an 80 wt% loading content of the complex exhibiting a PLQY of up to 62.5% and a high transparency of ∼89%. As a proof-of-concept experiment, the luminescent film was used to fabricate luminescent solar concentrators (LSCs), in which the strong luminescence effect of the luminescent film is responsible for its optical conversion efficiency of 1.46% with a G of 1.87. This study presents a new model system for the development of highly transparent LSCs by utilizing high loading contents of LnCs.