“…[118][119][120] Extensive research in this field was the topic of several reviews throughout years. [19][20][21][22][23][24] In a recent review, the SHG process in single crystals of CPs has been covered. 19 Keeping in mind already documented and reviewed advances, we would like to highlight only selected papers, which open up new directions in SHG-characterization of CPs.…”
Section: Shg and Thg In Cpsmentioning
confidence: 99%
“…To date, NLO studies have mostly been limited to the secondharmonic generation (SHG) [19][20][21][22][23][24] and only in recent years have a few publications appeared, in which other NLO properties such as multi-photon absorption and third-harmonic generation were explored. Also, recent reports introduced into the MOF discipline other advanced photonic applications and phenomena, such as up-conversion via triplet-triplet annihilation as well as lasing and stimulated emission.…”
The building block modular approach that lies behind coordination polymers (CPs) and metal-organic frameworks (MOFs) results not only in a plethora of materials that can be obtained but also in a vast array of material properties that could be aimed at. Optical properties appear to be particularly predetermined by the character of individual structural units and by the intricate interplay between them. Indeed, the "design principles" shaping the optical properties of these materials seem to be well explored for luminescence and second-harmonic generation (SHG) phenomena; these have been covered in numerous previous reviews. Herein, we shine light on CPs and MOFs as optical media for state-of-the-art photonic phenomena such as multi-photon absorption, triplet-triplet annihilation (TTA) and stimulated emission. In the first part of this review we focus on the nonlinear optical (NLO) properties of CPs and MOFs, with a closer look at the two-photon absorption property. We discuss the scope of applicability of most commonly used measurement techniques (Z-scan and two-photon excited fluorescence (TPEF)) that can be applied for proper determination of the NLO properties of these materials; in particular, we suggest recommendations for their use, along with a discussion of the best reporting practices of NLO parameters. We also outline design principles, employing both intramolecular and intermolecular strategies, that are necessary for maximizing the NLO response. A review of recent literature on two-, three- and multi-photon absorption in CPs and MOFs is further supplemented with application-oriented processes such as two-photon 3D patterning and data storage. Additionally, we provide an overview of the latest achievements in the field of frequency doubling (SHG) and tripling (third-harmonic generation, THG) in these materials. Apart from nonlinear processes, in the next sections we also target the photonic properties of MOFs that benefit from their porosity, and resulting from this their ability to serve as containers for optically-active molecules. Thus, we survey dye@MOF composites as novel media in which efficient upconversion via triplet energy migration (TEM) occurs as well as materials for stimulated emission and multi-photon pumped lasing. Prospects for producing lasing as an intrinsic property of MOFs has also been discussed. Overall, further development of the optical processes highlighted herein should allow for realization of various photonic, data storage, biomedical and optoelectronic applications.
“…[118][119][120] Extensive research in this field was the topic of several reviews throughout years. [19][20][21][22][23][24] In a recent review, the SHG process in single crystals of CPs has been covered. 19 Keeping in mind already documented and reviewed advances, we would like to highlight only selected papers, which open up new directions in SHG-characterization of CPs.…”
Section: Shg and Thg In Cpsmentioning
confidence: 99%
“…To date, NLO studies have mostly been limited to the secondharmonic generation (SHG) [19][20][21][22][23][24] and only in recent years have a few publications appeared, in which other NLO properties such as multi-photon absorption and third-harmonic generation were explored. Also, recent reports introduced into the MOF discipline other advanced photonic applications and phenomena, such as up-conversion via triplet-triplet annihilation as well as lasing and stimulated emission.…”
The building block modular approach that lies behind coordination polymers (CPs) and metal-organic frameworks (MOFs) results not only in a plethora of materials that can be obtained but also in a vast array of material properties that could be aimed at. Optical properties appear to be particularly predetermined by the character of individual structural units and by the intricate interplay between them. Indeed, the "design principles" shaping the optical properties of these materials seem to be well explored for luminescence and second-harmonic generation (SHG) phenomena; these have been covered in numerous previous reviews. Herein, we shine light on CPs and MOFs as optical media for state-of-the-art photonic phenomena such as multi-photon absorption, triplet-triplet annihilation (TTA) and stimulated emission. In the first part of this review we focus on the nonlinear optical (NLO) properties of CPs and MOFs, with a closer look at the two-photon absorption property. We discuss the scope of applicability of most commonly used measurement techniques (Z-scan and two-photon excited fluorescence (TPEF)) that can be applied for proper determination of the NLO properties of these materials; in particular, we suggest recommendations for their use, along with a discussion of the best reporting practices of NLO parameters. We also outline design principles, employing both intramolecular and intermolecular strategies, that are necessary for maximizing the NLO response. A review of recent literature on two-, three- and multi-photon absorption in CPs and MOFs is further supplemented with application-oriented processes such as two-photon 3D patterning and data storage. Additionally, we provide an overview of the latest achievements in the field of frequency doubling (SHG) and tripling (third-harmonic generation, THG) in these materials. Apart from nonlinear processes, in the next sections we also target the photonic properties of MOFs that benefit from their porosity, and resulting from this their ability to serve as containers for optically-active molecules. Thus, we survey dye@MOF composites as novel media in which efficient upconversion via triplet energy migration (TEM) occurs as well as materials for stimulated emission and multi-photon pumped lasing. Prospects for producing lasing as an intrinsic property of MOFs has also been discussed. Overall, further development of the optical processes highlighted herein should allow for realization of various photonic, data storage, biomedical and optoelectronic applications.
“…41,42 Metal-organic frameworks have been investigated as a route to obtain nonlinear optical molecular-based materials. 43,44 We quantified the SHG-response for the structure that has the highest SHG activity, namely CAU-10-NO 2 (4). Assuming monocrystalline particles, the effective second order nonlinear optical coefficient averaged over all orientations <d eff > was found to be 0.0002 pm/V (SI paragraph X).…”
Section: Correlation Of Sorption Properties and Structurementioning
Employing high-throughput methods, the synthesis conditions for a series of six new MOFs based on aluminium ions and the V-shaped linker molecule 1,3-benzene dicarboxylic acid, denoted as CAU-10-X (CAU = Christian-Albrechts-University) with the sum formula [Al(OH)(C 8 H 3 O 4 X)]•solvent, were established (X = functional group in 5-position of the aromatic ring; X = H (1), CH 3 (2), OCH 3 (3) NO 2 (4), NH 2 (5), or OH (6)). Due to the absence of macroscopic crystals, the obtained compounds were structurally characterized employing XRPD-methods. The crystal structures of 1, 2 and 3 were refined using Rietveld methods. Although the described MOFs are isoreticular, they crystallize in several, sometimes non-centrosymmetric space groups (1, 4, 6), due to slight structural changes induced by the functionalization. These space groups were confirmed with second-harmonic generation measurements. All compounds are highly stable as confirmed by temperature-dependent XRPD-and IR-experiments and decompose at temperatures above 350 °C. The stabilities of all compounds in aqueous solutions of varying pH were confirmed by XRPD-measurements and their sorption properties towards nitrogen, hydrogen, carbon dioxide and water vapor at low pressures are reported. A drastic influence of the functional group on affinity, capacity and accessibility of the pores for these gases is observed. These properties depend on the polarity and size of the functional group as well as on subtle structural differences between the CAU-10-X compounds.
“…Frequency mixing phenomena such as SHG (second-harmonic generation) and THG (third-harmonic generation) are nonlinear optical parametric processes in which the pumping laser radiation is nonresonantly transformed within the material (that is, without participation of photon absorption events by electron levels), as a result producing the radiation at two and three times shorter wavelengths, respectively. 1 An important feature of the former phenomenon, arising from the properties of the second-order optical susceptibility χ (2) tensor, is that it can be elicited only in crystalline materials featuring non-centrosymmetric space groups; hence, SHG can be treated as a spectroscopic tool for the determination of the "true" crystal non-centrosymmetry. The THG process, on the other hand, is described by the third-order optical susceptibility tensor χ (3) , which, in contrast to χ (2) , has non-zero components under all symmetries.…”
Section: Introductionmentioning
confidence: 99%
“…1 An important feature of the former phenomenon, arising from the properties of the second-order optical susceptibility χ (2) tensor, is that it can be elicited only in crystalline materials featuring non-centrosymmetric space groups; hence, SHG can be treated as a spectroscopic tool for the determination of the "true" crystal non-centrosymmetry. The THG process, on the other hand, is described by the third-order optical susceptibility tensor χ (3) , which, in contrast to χ (2) , has non-zero components under all symmetries. Accordingly, frequency tripling is achievable in any crystalline solid, thus in all CPs (coordination polymers).…”
The reaction of a phosphonate-diester tetraphenylmethane-based tecton, tetrakis[4-(diethoxyphosphoryl)phenyl]methane, (L) with cobalt(ii) chloride afforded a centrosymmetric coordination polymer (CP), [L·2Co(HO)·2CoCl], 2-Cl, possessing simultaneously octahedral (O) and tetrahedral (T) metal centers. This material served as a model compound for the demonstration of factors influencing the spectral dependence of one of the nonlinear optical (NLO) phenomena, the third-harmonic generation (THG). The spectrally-resolved THG (SR-THG) measurements in the range from 1125 to 1750 nm revealed that a maximum of THG response is obtained when the fundamental beam is around 1300 nm. The SR-THG study was combined with an analysis of the self-absorption effects of pumping and of third-harmonic radiation; based on these results, we put forward a hypothesis that the THG action spectrum is influenced more by the ability of the material to self-absorb the third harmonic rather than by the extent of self-absorption of the pumping radiation. Apart from investigations of NLO properties, we have explored coordination and particularly the supramolecular interactions that build up the 2-Cl CP. Despite the tetrahedral, spatial shape of the ligand L, CP 2-Cl has a two-dimensional net. The structure was found to be strongly supported by O-HCl hydrogen bonds, since each CoCl complex anion is an acceptor of eight of such interactions within a distorted square grid layer of cobalt(ii) ions. While coordination and hydrogen-bonded nets are both featuring the sql topology when treated separately, the consideration of both of them as topological paths yields a trinodal 4,4,6-connected net, described by the point symbol (4·8)(4·6)(4·6·8). SR-THG and structural studies of 2-Cl have been also supported by far- and mid-infrared spectroscopy, UV-Vis-NIR solid state absorption analysis, thermogravimetry and preliminary magnetic characterization.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.