Layer‐by‐Layer Assembly of Na₉[EuW₁₀O₃₆]⋅32 H₂O and Layered Double Hydroxides Leading to Ordered Ultra‐Thin Films: Cooperative Effect and Orientation Effect

Abstract

Well‐ordered, ultra‐thin films (UTFs) based on the hybrid assembly of Na9[EuW10O36]⋅32 H2O (denoted as EuW10) and exfoliated MgAl layered double hydroxide (LDH) monolayers have been fabricated by utilising a layer‐by‐layer (LBL) technique. The assembly process was monitored by UV/Vis absorption and fluorescence spectroscopy measurements to get a stepwise and regular growth of the UTFs upon increasing the deposited cycles. In the resulting (EuW10/LDH)n UTFs, the intercalation of EuW10 anions into LDH monolayers allows the UTFs to retain their optical properties. Meanwhile, LDH monolayers provide EuW10 with a confined and protective microenvironment to isolate them from each other between adjacent layers. The UTFs exhibit a periodic, long‐range, ordered structure. Anisotropic luminescence spectroscopy measurements show that the (EuW10/LDHs)n UTFs display well‐defined red luminescence with an anisotropy value, r, of about 0.15. Therefore, the cooperative and orientation effects between the host layers and guest anions play significant roles for the improved properties of the (EuW10/LDHs)n UTFs. This work could benefit the design and fabrication of novel electro‐optical devices based on the UTFs of hybrid materials.

Preparation and Properties of Transparent Ultrathin Lanthanide‐Complex Films

“…The thin films display uniform bright red or green luminescence with increasing intensity from 30 to 75 (or 20 to 80) bilayers. No clear red‐ or blue‐shift of the absorption and emission spectra for the (Eu(DPA) 3 3− /LDH) n and (Tb(DPA) 3 3− /LDH) n UTFs with a different number of bilayers were observed, which suggests that no intermolecular interactions between Eu(DPA) 3 3− or Tb(DPA) 3 3− clusters in the neighbouring layers were formed during the assembly process …”

Tailoring Hybrid Layered Double Hydroxides for the Development of Innovative Applications

“…Various photoresponsive LDH LbL‐multilayer films containing photoactive molecules or complexes have also been described, involving for instance poly(1‐4[4‐(3‐carboxy‐4‐hydroxyphenylazo) benzenesulfonamido]‐1,2‐ethanediyl sodium salt), 1,3,6,8‐pyrenetetrasulfonic acid, Na 9 [EuW 10 O 36 ], 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonate), hydroxide/8‐amino‐1,3,6‐naphthalenetrisulfonate, calcein, spiropyran, luminol, and erythrosine B . Such a self‐assembly approach via electrostatic interactions was further adapted to coimmobilize two types of anionic dye molecules, i.e., tetrakis(4‐carboxyphenyl)porphyrin or perylene 3,4,9,10‐tetracarboxylate with polymer anions such as poly 4‐styrene sulfonate and poly vinyl sulfonate .…”

A Multifunctional Dual-Luminescent Polyoxometalate@Metal-Organic Framework EuW10@UiO-67 Composite as Chemical Probe and Temperature Sensor

“…Inversely, it was found that acidic AAs quench the luminescence while nonpolar AAs do not significantly influence the optical properties of the POM (Zhang et al, 2016 ). The processing of EuW 10 by incorporation into films has been achieved, allowing the fabrication of moisture-responsive systems (Clemente-León et al, 2010 ; Xu et al, 2011 ; Qiu et al, 2015 ). Based on all these results, we have undertaken to elaborate a multi-functional hybrid system where the EuW 10 POM is incorporated in the cavities of a metal-organic framework (MOF).…”