Crystalline Porous Materials for Nonlinear Optics

Abstract

metal chalcogenides, [17,18] graphdiyne, [19][20][21] etc.) and perovskites [22][23][24][25][26] have been in a state of vigorous development and rapid advances for applications in optoelectronics, catalysis, energy conversion, due to their autologous admirable chemistry and physics characteristics. [27,28] Porous materials, a scientifically evolving and functionally compelling class of solid compounds with well-defined pore structures, such as metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and polyoxometalates (POMs), have attracted broad research interest because of their wide applications in many fields including, but not limited to, adsorption, separation, catalysis, and photovoltaics. [29][30][31][32] Through fine control over the organic units to create predesigned skeletons, an exceptionally large set of materials with unique porous structures and remarkable properties have been developed. [33,34] MOFs, also known as coordination polymers or coordination networks, are one class of crystalline porous materials prepared by the self-assembly of metal ions or clusters with organic ligands. [35] They have drawn tremendous research interest for their customizable chemical structures along with unique chemical and physical properties, [36][37][38][39][40][41] which guarantee their wide applications as adsorption and separation, catalysts, magnetic, and light emitting materials. [36,[42][43][44][45] The use of appropriate ligands with optimized electronic push-pull structures, the degree of conjugation in the system and the encapsulation of guest molecules with different properties are some of the effective strategies to enhance the linear and nonlinear optical properties of the MOFs materials. [46][47][48] COFs, constructed from organic moltifs linking through strong covalent bonding, are a kind of crystalline porous materials in which the atoms of organic units are precisely integrated to create periodic frameworks and nanopores. [49,50] Although the thermal stability and crystallinity of COFs are lower than MOFs, they have received wide attention due to their low density, large surface area and strong ππ stacking. [51][52][53][54] It has been appreciated that the applications of COFs materials in third-order NLO such as two-photon fluorescence have been well developed in recent years. [55][56][57] Similar to MOFs and COFs, POMs formed by the coordination of early transition metals and oxygen atoms are a class of crystalline porous materials with unique structures and properties for their exceptional crystallinity and high stability. [58] POMs are intrinsically electron deficient, and their electronaccepting capability in combination with highly delocalized π-conjugated systems is particularly promising for producing NLO materials. [59,60] The structure of all the crystalline porous Crystalline porous materials have been extensively explored for wide applications in many fields including nonlinear optics (NLO) for frequency doubling, two-photon absorption/emission, optical limiting effect,...

Oriented Assembly of 2D Metal-Pyridylporphyrinic Framework Films for Giant Nonlinear Optical Limiting

“…Third-order nonlinear optical (NLO) materials have recently received significant attention owing to their potential civilian and military applications in optical limiting (OL), mode-locked laser systems and optical switching, etc. − Many efforts made in third-order NLO materials mainly include organic molecules, inorganic semiconductors, carbon materials, and inorganic–organic hybrid materials, etc. − As a kind of ordered crystalline network material, metal–organic frameworks (MOFs) − assembled by metal nodes (or clusters) and organic linkers via coordination bonding have been widely reported in various optical fields including NLO behavior, − photodetectors, photocatalysis, − and so on. , As a branch of MOFs, porphyrinic MOFs are attracting great attention on the third-order NLO performance because of their highly delocalized π-electronic conjugated system. , Generally, 3D porous porphyrinic MOFs with a weak π–π interaction have greatly limited performance, and they usually need to be loaded with guest species in their pores to enhance the third-order NLO performance. , Instead, 2D porphyrinic MOFs possess a huge number of π–π interactions between layers. Great efforts in exploring the NLO properties of MOFs have been made, but third-order NLO in 2D MOFs with abundant π–π stacking have rarely been studied.…”

Coordination Polymers Based on Carbazole-Derived Chromophore Linkers for Optimized Multiphoton Absorption: A Structural and Photophysical Study

“…13 Ba(fbcd)(DMAc) 2.5 (H 2 O) 1. 5 . In a 4 mL screw cap vial, 10 mg of H 4 fbcd and 11.12 mg of Ba(NO 3 ) 2 (3 equiv) were dissolved in a DMAc/water mixture (2/0.25 mL) and heated at 100 °C for 2 days.…”

Tunable third-order nonlinear optical effect via modifying Ti4(embonate)6 cage-based ionic pairs

“…In recent years, third-order nonlinear optical (NLO) materials have attracted considerable attention due to their potential applications in optical switching, optical limiting, logic devices, image transmission and mode-locked laser systems, etc. [1][2][3][4][5][6][7][8] Nonlinear optical effects, including nonlinear absorption, [9][10][11][12][13][14][15] Kerr nonlinearity and four wave mixing, [16][17][18] have been extensively studied. Among them, research into nonlinear absorption effects (including saturated absorption (SA) and reverse saturated absorption (RSA)) has been one of the most attractive and intensive research directions.…”