Flexible Excitation Dynamics, Fluorescence, and Polarized Photoluminescence of Eu 2 O 3 Nanoparticles Decorated 4MB4BA and 4P4MB Nematic Liquid Crystals and Their Photochemical Quantum Yields

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In the present research work, a new series of Eu 2 O 3 @N‐(4‐methoxybenzylidene)‐4‐butylaniline (4MB4BA) and Eu 2 O 3 @4‐pentylphenyl 4‐methoxybenzoate (4P4MB) liquid crystal nanocomposites (LCNCs) were prepared using ultrasonication method. The phase transition temperatures of Eu 2 O 3 @4MB4BA and Eu 2 O 3 @4P4MB LCNCs occurred during heating at 55 and 43.6 °C and during cooling at 38.6 and 41 °C. X‐ray photoelectron spectroscopy (XPS) studies confirmed the presence of C 1s, O 1s, N 1s, Eu 3d orbitals, and good incorporation of Eu 2 O 3 nanoparticles. The Zeta potential studies of Eu 2 O 3 @4MB4BA and Eu 2 O 3 @4P4MB LCNCs showed −7.745 × 10 −5 and −0.011 V (anionic character) with conductivity ranges between 0.006612 and 0.00966 mS/cm. The Eu 2 O 3 @4MB4BA at λ excitation = 320 and 350 nm displayed broad emission bands with blue, green, orange, and red vibrant colors. However, Eu 2 O 3 @4P4MB (350 nm filter) displayed blue, orange, and red colors with sharp emission bands. The average lifetime and photochemical quantum yields were found 1.033 and 0.262 ns, and 0.17%–1.14% for Eu 2 O 3 @4MB4BA & Eu 2 O 3 @4P4MB LCNCs, respectively. The polarized photoluminescence of Eu 2 O 3 @4MB4BALCNCs at 0°, 90° phase angles ( θ ) showed defect‐centered emission wavelengths ( λ excitation = 350 nm). Further, Eu 2 O 3 @4P4MB LCNCs using 395 nm filter shifted the emission band from blue (431 nm, E g ‐2.89 eV) to orange (616 nm, E g ‐2.02 eV) at 0° phase angle. At 90° phase angle, the emission band shifted from blue (430 nm, E g ‐2.89 eV) to red (626 nm, E g ‐1.97 eV). These LCNCs are potential candidates for advanced fluorescent, luminescent, and electro‐optical applications.