LiF Nanoparticles Enhance Targeted Degradation of Organic Material under Low Dose X-ray Irradiation

Abstract

The targeted irradiation of structures by X-rays has seen application in a variety of fields. Herein, the use of 5–10 nm LiF nanoparticles to locally enhance the degradation of an organic thin film, diindenoperylene, under hard X-ray irradiation, at relatively low ionizing radiation doses, is shown. X-ray reflectivity analysis indicated that the film thickness increased 12.04 Å in air and 11.34 Å in a helium atmosphere, under a radiation dose of ∼65 J/cm2 for 3 h illumination with a bi-layer structure that contained submonolayer coverage of thermally evaporated LiF. This was accompanied by significant modification of the surface topography for the organic film, which initially formed large flat islands. Accelerated aging experiments suggested that localized heating was not a major mechanism for the observed changes, suggesting a photochemical mechanism due to the formation of reactive species from LiF under irradiation. As LiF has a tendency to form active defects under radiation across the energy spectrum, this could could open a new direction to explore the efficacy of LiF or similar optically active materials that form electrically active defects under irradiation in various applications that could benefit from enhanced activity, such as radiography or targeted X-ray irradiation therapies.

Misuse of XPS in Analyzing Solid Polymer Electrolytes for Lithium Batteries

“…One of the most reported X-ray-sensitive elements in materials for energy storage and conversion is fluorine. [3][4][5][6][7][8][9] Despite the literature concerning degradation of samples during XPS measurements, more and more articles neglect this issue. [10][11][12] Most present subtle work relating surface species to battery electrochemical performance.…”

HF-Free synthesis of colloidal Cs2ZrF6 and (NH4)2ZrF6 nanocrystals

“…Fluoride NCs based on divalent (e.g., SrF 2 , FeF 2 , MnF 2 ) and monovalent (e.g., NaF, LiF) cations have also been widely investigated. [5][6][7][8] Despite the tremendous popularity of colloidal fluoride NCs, however, those involving tetravalent cations (such as A 2 BF 6 , A + = K + , Na + , Cs + ; B 4+ = Zr 4+ , Si 4+ , Ti 4+ , Ge 4+ , Sn 4+ ) remain almost completely unexplored. In bulk, A 2 BF 6 lattices doped with Mn 4+ ions are leading candidates for narrow-line red emitters in display and lighting technologies, 9,10 and those doped with Re 4+ show efficient upconversion.…”