White Light Emission and Second Harmonic Generation from Secondary Group Participation (SGP) in a Coordination Network

Abstract

We describe a white emitting coordination network solid that can be conveniently applied as a thin film onto a commercial UV-LED lamp for practical white lighting applications. The solid state material was discovered in an exercise of exploring molecular building blocks equipped with secondary groups for fine-tuning the structures and properties of coordination nets. Specifically, CH(3)SCH(2)CH(2)S- and (S)-CH(3)(OH)CHCH(2)S- (2-hydroxylpropyl) were each attached as secondary groups to the 2,5- positions of 1,4-benzenedicarboxylic acid (bdc), and the resultant molecules (L1 and L2, respectively) were crystallized with Pb(II) into the topologically similar 3D nets of PbL1 and PbL2, both consisting of interlinked Pb-carboxyl chains. While the CH(3)S- groups in PbL1 are not bonded to the Pb(II) centers, the hydroxy groups in PbL2 participate in coordinating to Pb(II) and thus modify the bonding features around the Pb(II), but only to a slight and subtle degree (e.g., Pb-O distances 2.941-3.116 Å). Interestingly, the subtle change in structure significantly impacts the properties, i.e., while the photoluminescence of PbL1 is yellowish green, PbL2 features bright white emission. Also, the homochiral side group in PbL2 imparts significant second harmonic generation, in spite of its seemingly weak association with the main framework (the NLO-phore). In a broad perspective, this work showcases the idea of secondary group participation (SGP) in the construction of coordination networks, an idea that parallels that of hemilabile ligands in organometallics and points to an effective strategy in developing advanced functions in solid state framework materials.

Luminescence and energy transfer of Eu3+ or/and Dy3+ co-doped in Sr3AlO4F phosphors with NUV excitation for WLEDs

“…However, at the 2h value of 44°, less intense unidentified diffraction peak was observed in the Dy 3+ and the (Eu 3+ , Dy 3+ ) co-doped phosphors; a similar phenomenon was also observed in other published reports of rare earth doped Sr 3 AlO 4 F [17,21].As the peak is not related to any individual element or the Sr 3 AlO 4 F compound, we consider it as an impurity peak. It is reported previously that [22], the Sr 3 AlO 4 F host lattice contains two different cation (Sr 2+ ) sites: one [marked as Sr (1)] is located in the layer where the AlO 4 tetrahedral is located and is coordinated by eight oxygen and two apical fluorine; the other one [Sr (2)] is eight coordinated by two fluorides within the Sr(2) 2 F 3+ plane and three oxygen atoms above and three below its plane. Because the coordination environments of the two Sr sites in the compound are noticeably different, it is possible that Sr 2+ ions ordering can be induced by replacing Sr 2+ with another alkaline earth ion, or possibly even a RE ion and alkali metal cation pair.…”

“…The progress of white-light-emitting diodes (WLEDs) is believed to be leading the way in new solid-state lighting device generation due to the benefits of high brightness, small volume, energy savings, long durability, and environmental benefits in a number of applications [1][2][3]. White light is normally produced through exciting multi-phosphors by a UV LED, mixing a blue LED with a yellow phosphor, or blending multi-LEDs [4,5].…”

“…Moreover, the fluoride lattice provides for the high coordination number for the doped rare-earth ions and the high iconicity of the rare-earth (RE) to fluorine bond results in a very wide-band gap, low vibrational energies and low probability of inter-configurational transitions [13,14]. Recently, a family of anion ordered oxyfluorides with a general composition A(1) 3Àx A (2) [15][16][17]. It was also found that the PL properties and the CIE values of the designed phosphors could be tailored by the various chemical substitutions Sr for Ba and/or Ca.…”

High-Performance Blue-Excitable Yellow Phosphor Obtained from an Activated Solvochromic Bismuth-Fluorophore Metal–Organic Framework

“…[1][2][3][4][5][6][7][8][9] Our recent work has established that LMOFs with strong yellow emission are potentially suitable to serve as the yellow phosphor in commercial blue light driven phosphor-converted white light-emitting diodes (PC-WLEDs), 10,11 which are rapidly replacing traditional lighting technologies (incandescent, compact fluorescent), thanks to their lower energy consumption and longer lifetime. 12 A common type of PC-WLEDs utilizes a blue LED to excite a yellow phosphor, such as yttrium aluminum garnet doped with cerium (YAG:Ce 3+ ), resulting in white light through the combination of the blue and yellow emissions.…”

Assembly of 1,3,5-tris(2-alkylthiol-pyrimidin-4-yl)benzene) (alkyl = Me, n-Pr) with copper(I) iodide: effect of alkyl side chain

“…Great achievements have been made to tailor the structure and function of coordination polymers by means of the core functionalization of organic component, since the inner coordination information with organic building block can be altered in this way, which would lead to significant structural variations of coordination polymers. By contrast, less attention has been paid to the periphery of organic building blocks such as the attached side chain [3,4]. However, the side chain effect has been widely used as an elegant tool to finely modulate the molecular packing that is associated with the final solid-state properties of organic materials [5][6][7][8].…”