A First Wide‐Open LDH Structure Hosting InP/ZnS QDs: A New Route Toward Efficient and Photostable Red‐Emitting Phosphor

Abstract

The architecture of Zn‐Al layered double hydroxides (LDHs), organo‐modified with bola‐amphiphiles molecules, is matching its interlayer space to the size of narrow‐band red‐emitting InP/ZnS core–shell quantum dots (QDs) to form original high‐performance functional organic–inorganic QD‐bola‐LDH hybrids. The success of size‐matching interlayer space (SMIS) approach is confirmed by X‐ray diffraction, small angle X‐ray scattering (SAXS), TEM, STEM‐HAADF, and photoluminescence investigations. The QD‐Bola‐LDH hybrid exhibits a photoluminescence quantum yield three times higher than that of pristine InP/ZnS QDs and provides an easy dispersion into silicone‐based resins, what makes the SMIS approach a change of paradigm compared to intercalation chemistry using common host structures. Moreover, this novel hybrid presents low QD–QD energy transfer comparable to that obtained for QDs in suspension. Composite silicone films incorporating InP/ZnS (0.27 wt%) QD‐bola‐LDH hybrids further show remarkable improved photostability relative to pristine QDs. An LED overlay consisting of a blue LED chip and silicone films loaded with QD‐bola‐LDH hybrids and YAG:Ce phosphors exhibits a color rendering index close to 94.

Narrow‐Band Blue‐Emitting Indium Phosphide Quantum Dots Induced by Highly Active Zn Precursor

“…In recent years, colloidal quantum dots (QDs) have drawn great attention because of the excellent optical and electronic properties induced by their unique quantum confinement. [1][2][3][4][5][6][7][8] By controlling the size and composition of colloidal particles, the electronic and optical properties of QDs can be easily tuned. The QDs possess many advantages such as continuously adjustable emission wavelength, narrow band emission, high quantum efficiency, etc., which makes QDs attractive for applications in light emitting diodes (LED, Mini/Micro-LED), displays, biomedical imaging, photoelectric detection, solar cells, and other fields.…”

Interleaved Electroactive Molecules into LDH Working on Both Electrodes of an Aqueous Battery-Type Device

“…They consist of edge-sharing metal hydroxide octahedra of brucite-type structure in which a partial substitution of divalent to trivalent cations produces an excess of a positive charge of layers that is compensated by the presence of anions between the layers. Large cumbersome species have been hosted into LDH interlayer spaces to provide stability and prevent their migration when exposed to external stresses or dispersed in a polymer for red-emitting quantum dots, for example [ 42 ]. In the same vein, we focus here with a common LDH, the hydrotalcite of general composition Mg 2 Al(OH) 6 -A·nH 2 O hereafter labelled as Mg 2 Al-A, where A would be the electroactive interleaved molecule.…”

Elucidating the effect of the spacer and the luminescence mechanism of SRB hosted in a LDH interlayer

“…19 In previous studies, the benefits in terms of optical performance of incorporating concomitantly two organic molecules, dodecylsulftate (DS) as surfactant molecule and SRB in a restricted space like LDH have been underlined 20 and can be summed up as follows: -increase in photoluminescence quantum yield, -increase in thermal stability, -possibility of elaborating luminescent coatings on quartz substrate 21 or by mixing the HDL-Spacer/SRB composite powder into a silicone matrix. As evidenced by Costantino et al 18 , organic molecules may sometimes be simply adsorbed onto the surface of HDL sheets, and intercalation requires the distance between each HDL matrix sheet to be adjusted to the size of the luminescent molecule guest, this being reminiscent of the recently-developed "size-matching interlayer space" (SMIS) approach 22 .…”