Thermochromism of Highly Luminescent Photopolymer Flexible Films Based On Eu (III) Salts Confined in Polysulfone

• Main Authors: Mani Outis, João Paulo Leal, Maria Helena Casimiro, Bernardo Monteiro, Cláudia Cristina Lage Pereira
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Materials
• Subjects: thermal behavior; lanthanide; β-diketonate; polysulfone; polymer films; europium (III), hybrid materials
• Online Access: https://www.mdpi.com/1996-1944/13/23/5394
• ISSN: 1996-1944

Here we discuss the influence of two different cations on the emissive properties of the highly emissive [Eu(fod)₄]⁻ anion. The studied Eu(III) salts were [C₁₆Pyr][Eu(fod)₄] (<b>1</b>), and the previously reported [Chol][Eu(fod)₄]. C₁₆Pyr stands for N-cetylpyridinium, Chol for cholinium and fod for 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dionate. <b>1</b> is classified as ionic liquid, with melting point close to 60 °C, and presented a luminescence quantum yield of (ϕ) 100%. Ultrabright emissive photopolymers were obtained for the first time using polysulfone as the host matrix. The films were prepared with incorporation of 10% (<i>w</i>/<i>w</i>) of <b>1</b> and <b>[Chol][Eu(fod)₄]</b> in the polymeric matrix, which improved its thermal stability. Additionally, the luminescence of <b>CholEu(fod)₄/PSU</b> presented a strong temperature dependence with a ratiometric thermal behavior.