RESUMO
The mushrooming utilization of electronic devices in the current era produces electromagnetic interference (EMI) capable of disabling commercial and military electronic appliances on a level like never before. Due to this, the development of advanced materials for effectively shielding electromagnetic radiation has now become a pressing priority for the scientific world. This paper reviews the current research status of polymer nanocomposite-based EMI shielding materials, with a special focus on those with hybrid fillers and MXenes. A discussion on the theory of EMI shielding followed by a brief account of the most popular synthesis methods of EMI shielding polymer nanocomposites is included in this review. Emphasis is given to unravelling the connection between microstructures of the composites, their physical properties, filler type, and EMI shielding efficiency (EMI SE). Along with EMI shielding efficiency and conductivity, mechanical properties reported for EMI shielding polymer nanocomposites are also reviewed. An elaborate discussion on the gap areas in various fields where EMI shielding materials have potential applications is reported, and future directions of research are proposed to overcome the existing technological obstacles.
RESUMO
Eu3+ doped silica-titania-polydimethylsiloxane hybrid ORMOSILs were synthesized via a non-hydrolytic sol-gel route. The structural and thermal analyses of the samples confirmed that the matrix structure remains unaffected by doping with different concentrations of Eu3+ ions. Photoluminescence (PL) studies performed at 394 nm on Eu3+ doped ORMOSILs imply that they emit broad blue host emission and the characteristic Eu3+ red emissions simultaneously. Also, the samples were excited at the charge transfer (CT) band and this confirmed the existence of an energy transfer path from the host to the Eu3+ ions via Ti4+-O2--Eu3+ bonds. The phonon energy of the host matrix was estimated by phonon sideband (PSB) analysis and the results were substantiated by Raman analysis. Judd-Ofelt (JO) parameters were also evaluated which give details about the local surroundings of the Eu3+ ions in the system and these parameters were further used for predicting the radiative properties of 5D0 â 7F1,2,4 transitions of Eu3+ ions. Furthermore, the quantum efficiency and CIE co-ordinates were evaluated and it was found that Eu3+ doped silica-titania-polydimethylsiloxane ORMOSIL has an intense pinkish red emission with a quantum efficiency of 30.7%.
