Luminescent and Transparent Nanocellulose Films Containing Europium Carboxylate Groups as Flexible Dielectric Materials
Quanling Yang, Chenggang Zhang, Zhuqun Shi, Jinyu Wang, Chuanxi Xiong, Tsuguyuki Saito, Akira Isogai
ACS Applied Nanomaterials
Transparent, flexible, and luminescent 2,2,6,6-tetramethyl-piperidine-1-oxyl radical-oxidized cellulose nanofibril films with europium carboxylate groups (TOCN-Eu) are proposed as potential flexible dielectric materials. The TOCN-Eu films were prepared from TOCN films with sodium carboxylate groups (TOCN-Na) by immersion in Eu(NO3)3 solution and subsequent washing with water and drying of the wet TOCN-Eu hydrogel films. The nanolayered TOCN-Eu films emit red light under ultraviolet-light irradiation and exhibit greatly improved dry and wet mechanical properties, water resistance, thermal stability, oxygen-barrier properties, dielectric breakdown strength, and energy density than conventional TOCN-Na films. These characteristic properties of the TOCN-Eu films are most likely caused by the formation of strong ionic bonds between the carboxylate groups and Eu3+ ions. These high-performance cellulose nanofibril films are promising for application as multifunctional materials in light-emitting, photovoltaic, and energy storage devices.
Fluorescence, Photoluminescence, Solid state, Nanostructures, Optical properties, Materials