2.2. Preparation of the polymeric luminescent films
The polymeric luminescent films were prepared as follows: (i) several samples containing 1–7 mg of the complex were dissolved in 7 mL of CH2Cl2 in a refrigerated ultrasonic bath; (ii) then, 70 mg of
PMMA were added and themixture and stirred until complete solution of the polymer, obtaining sampleswith relative concentration of the active species ranging from5 to 20wt%; and (iii) tape casting (TC) or spincoating (SC) techniques were used for film deposition (50–100 μm) on commercial PV glass substrates (Pilkington). This compound has been selected from many other Eu(III) complexes because of its high luminescence and its solubility in dichloromethane which is also a good solvent for PMMA. The PMMA is preferred because of its optical transparency, its resistance to the impacts and its chemical stability [26–29]