Hierarchical self-supported ZnAlEu LDH nanotubes hosting luminescent CdTe quantum dots

Abstract

Self-supported oligo-layered ZnAlEu LDH nanotubes (∅ 20 nm) self-assemble upon controlled hydrolysis of the metal ions (Zn, Al, Eu) in the presence of 1,3,5-benzenetricarboxylate anions and non-ionic worm-like micelles. Their high surface area and easily accessible cylindrical mesopores (175 m g; 0.75 cm g) facilitate interaction with 5 nm CdTe quantum dots, enhancing the overall luminescence behavior.

Luminescent Layered Double Hydroxides Intercalated with an Anionic Photosensitizer via the Memory Effect

“…From the partially overlapped (110) and (113) reflections around 60.45 2θ, the metal-to-metal distance within the hydroxide layers could also be estimated as 'a = 2d(110) = 3.06 Å' [3]. The (00l) basal reflections of the ZnAlEu-BTC LDHs at 6.6°, 13.2°, 20.2°, and 26.2° 2θ confirmed the basal spacing of 13.4 Å previously reported for BTC-intercalated LDHs (as illustrated in Figure 2C) [7]. LDHs can be dehydrated and dehydroxylated by calcination at temperatures as low as 200 °C [31].…”

“…Synthetic LDHs exhibit a wide flexibility in their composition, as a score of metal cations and polyvalent anions can be introduced in the structure, tuning their chemico-physical properties [1][2][3]. By changing both the interlayer and the metal components, LDHs have been tuned towards different applications, serving as heterogeneous catalysts, catalyst supports [4], water treatment agents [5], luminescent materials [6][7][8][9], etc. Synthetic LDHs exhibit a wide flexibility in their composition, as a score of metal cations and polyvalent anions can be introduced in the structure, tuning their chemico-physical properties [1][2][3].…”

“…Different applications can be explored for different chemical compositions. For instance, Wong et al [27] have shown that the memory The introduction of trivalent rare earth elements (RE 3+ ) in LDH matrixes has revealed a series of 2D structured materials that have promising luminescent properties [7,10]. Rare earth elements form a subgroup of column 3 in the periodic table and exhibit very low influence of the ligand field in the energy of their spectral lines.…”

Possibilities for layered double hydroxides (LDH) nanotubes in biological applications

“…First the delamination of this material in sheets of double hydroxides 3,4 or alternatively, as proposed by our group, the structuring of the LDHs in the form of nanotubes which has been shown to considerably increase their surface area and, consequently, their adsorption capacity. The high-surface area presented by the LDH nanotubes and their easily accessible cylindrical mesopores described by Morais et al 5 offers a new class of lamellar materials, where both the symmetrical spacings and the central mesopore are able to perform different functions. In fact, while the mesopore (central cavity of the tube) is accessible for the adsorption of large molecules, the spacing between the layers of hydroxides remains available for the intercalation of anionic antenna molecules that can enhance the luminescent properties of the nanotubes making them suitable for applications as biological markers.…”

Preparação e estudo de nanotubos luminescentes de hidróxidos duplos lamelares (LDH) contendo íons terras raras

“…A subsequente extração destes agentes estruturantes através de lavagem com metanol resultou em uma rede de nanotubos cilíndricos, ocos e interconectados, formados pela deposição de multicamadas de hidróxidos duplos intercalados pela molécula sensibilizadora ácido benzeno-1,3,5tricarboxílico (ácido trimésico, BTC). A combinação de Eu 3+ (nas camadas de hidróxidos) e BTC no meio interlamelar resultou em nanotubos [38] com propriedades luminescentes, demonstrando de maneira notável como modificações químicas e morfológicas nos LDHs podem levar ao remodelamento das suas propriedades físico-químicas e, consequentemente, direcionar suas aplicações de maneira desejável. nanoesfera oca (centro) e nanoenrolamento (direita).…”