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来自 : www.oalib.com/references/13145 发布时间：2021-03-25

ABSTRACT: The new reactive chemical vapor deposition (RCVD) method has been proposed for thin film deposition of luminescent nonvolatile lanthanide aromatic carboxylates. This method is based on metathesis reaction between the vapors of volatile lanthanide dipivaloylmethanate (Ln(dpm)3) and carboxylic acid (HCarb orH2Carb′) and was successfully used in case of HCarb. Advantages of the method were demonstrated on example of terbium benzoate (Tb(bz)3) and o-phenoxybenzoate thin films, and Tb(bz)3 thin films were successfully examined in the OLED with the following structure glass/ITO/PEDOT:PSS/TPD/Tb(bz)3/Ca/Al. Electroluminescence spectra of Tb(bz)3 showed only typical luminescent bands, originated from transitions of the terbium ion. Method peculiarities for deposition of compounds of dibasic acids H2Carb′ are established on example of terbium and europium terephtalates and europium 2,6-naphtalenedicarboxylate. 1. Introduction A search for new electroluminescent (EL) materials for organic light-emitting diodes (OLEDs) is still an actual challenge for chemists. The solution of it means not only finding a compound which fits the EL material requirements but also the right choice or creation of a technique providing the transformation of such precursors into the thin films of high smoothness and low thickness. This can be demonstrated on examples of lanthanide coordination compounds which are well-known potential luminescent materials [1–5]. However, it is not that simple to find among them the luminescent lanthanide coordination compound, which demonstrates simultaneously high thermal and UV stability, bright luminescence, while being volatile or possesses high solubility to deposit thin film of high quality by physical methods from gas phase or solutions. In case of highly volatile β-diketonates the obvious physical deposition technique allows to obtain thin films of high quality, and their luminescence efficiency can be increased by variation of the substituents in ligands. However these compounds do not exhibit required UV stability. A different situation arises from lanthanide aromatic carboxylates which show high UV, thermal, and chemical stability, as well as high luminescence efficiency, which can reach 100% in case of Tb(bz)3 [6–9], but for these compounds the choice for the film deposition technique among known methods appears rather impossible. The aromatic carboxylates form extremely rigid 3D networks [10–12], which make them nonvolatile and poorly soluble in organic solvents that complicate deposition of their thin films from gas phase or solution and