A New Class of Lasing Materials: Intrinsic Stimulated Emission from Nonlinear Optically Active Metal–Organic Frameworks

Abstract

Stimulated emission as the new intrinsic property of metal-organic frameworks is demonstrated in article number 1605637 by Roland A. Fischer and co-workers, by the observation of stimulated emission peak, and time-resolved photoluminescence, along with the support of density of state calculations. The results identify that immobilization of strong luminescent chromophores between the metal-nodes leads to the formation of the materials with enhanced stability and optical behavior for the next generation solid-state lasers. Dual-Ion Batteries In article number 1606805, Yongbing Tang and co-workers report a bubble-sheet-like aluminum foil used as anode and current collector in a dual-ion battery. This novel structure helps guide the Al-Li alloying position and confines the volumetric change, and thus results in excellent long-term cycling stability, featuring 99% capacity retention within 1500 cycles at 2 C. Ionic-Liquid Gating Ionic-liquid-gating control of interfacial magnetic aniso-tropy in Au/[DEME]+[TFSI]-/Co/SiO 2 multilayer structures is quantitatively determined by the electron spin resonance method, as described in article number 1606478 by Ziyao Zhou, Ming Liu and co-workers. A reproducible, reversible ferromagnetic resonance field shift of 219 Oe at an applied voltage of 1.5 V, with a large ME tunability of 146 Oe V −1 , is achieved, assisted by the electric double layers at the room temperature. Magnetic Memory In article number 1606748, Yossi Paltiel and co-workers use 30-50 nm ferromagnetic nanoplatelets (FMNPs) on top of an organic chiral molecule monolayer to demonstrate nano-based magnetless magnetic memory device at ambient temperatures. The memory is based on the chiral induced spin selectivity effect. This technology could make it possible to create inexpensive, high-density universal memory devices with much lower power consumption than existing technologies. Additive Manufacturing of Metal Structures at the Micrometer Scale To enable the additive manufacturing of metals at the micrometer scale, a variety of novel techniques are currently in use. The individual techniques are introduced, detailing their underlying principles. Furthermore, it critically compares their fabrication capabilities, in particular the minimum feature size, achievable geometry and obtained materials properties. Blue-color stimulated emission with low threshold power is observed from In-and Zn-MOFs, which feature a highly fluorescent chromophore densely packed and rigidly linked to the metal-ion centers in the solid state. The density-of-states and transition dipole moments are calculated and the stimulated emission phenomenon is correlated with these properties. Dual-Ion Batteries A bubble-sheet-like aluminum foil is developed and used as anode material and current collector in a dual-ion battery (DIB). This novel structure helps guide the AlLi alloying position within the hollow nano-spheres and confines the alloy sizes. As a result, this design significantly relieves the volumetric change, and thus maintains ultrasta...

On the Existence of Excitonic Signatures in the Optical Response of Metal–Organic Frameworks: Comment on “van der Waals Metal–Organic Framework as an Excitonic Material for Advanced Photonics”

“…Our conclusions are also confirmed by the results of another recent study on similar MOF systems. [19] Finally, we would like to stress that our analysis does not rule out the possibility of the exciton formation in MOFs completely, which was convincingly demonstrated in a series of previous reports. [2][3][4][5] However, it shows that some features of the optical response of MOFs that can seem, at first glance, excitonic, can be, in fact, attributed to single-particle excitations.…”

“…One clearly sees that a single-particle transition between the narrow π bands discussed above are indeed possible and lead to the formation of the peak for photon energies of about 2.6-2.7 eV, in full agreement with the experimental data of Milichko et al [6] We stress once more that the origin of this peak is fully single particle and has nothing to do with excitonic effects. [19] Finally, we would like to stress that our analysis does not rule out the possibility of the exciton formation in MOFs completely, which was convincingly demonstrated in a series of previous reports. Indeed, the binding energy of the putative interlayer exciton was claimed to be bigger than one for intralayer excitons, which contradicts the physical sense (indeed, if an electron and hole are placed in different layers, the distance between them becomes bigger and thus the electron-hole interaction is attenuated).…”

Multi‐Photon Absorption in Metal–Organic Frameworks

“…Thet wo MOFs 3 and 4 give the strongest action cross-section values (hs 2 = 3582 GM and 2590 GM, respectively) ever found for any solid MPAmaterial. [15] TheZr-based materials 1, 3,and 4 show higher 2PA, 3PA, and 4PAa ction cross-section values than their respective Hf analogues.Although the cubic MOFs 1 and 2 have ah igher TCPE concentration, they show reduced, however, still very high 2PAa ction cross-section values compared to dyes,quantum dots,porphyrins,and other MOFs (see Supporting Information, Section 3);t he same trend holds for the 3PAa nd 4PA ( Figure 3b).…”

Room-temperature sintered metal-organic framework nanocrystals: A new type of optical ceramics

“…The cubic crystal symmetries (absence of the birefringence which causes extremely high scattering losses) are generally required for the crystallites of optical ceramics, meaning that only a few inorganic materials can be used. Besides, ceramics sintering usually operates above 1000 o C, which excludes organic and organic-inorganic hybrid materials [1].Porous coordination polymers (PCPs) or metal-organic frameworks (MOFs) are crystalline materials consisting of metal ions and organic ligands, which have captured widespread attentions for adsorption, catalysis, sensing, optics [6] and also laser gain mediums [7][8][9][10][11]. As can be seen in membranes and photonic crystals [12,13], MOF nanocrystals may merge to form seamless microscopic blocks under mild conditions [14][15][16].…”