Integrating metal−organic framework (MOF)− covalent organic framework (COF) allows versatile engineering of hybrid materials with properties superior to pristine components, especially COFs suffered from aggregation-caused quenching (ACQ), unlocking more possibilities to improve the luminescence of COFs. In this work, we prepared various MOF@ COF composites with different COF layer thicknesses, in which stable UiO-66-NH 2 served as the inner substrate and 1,3,5benzenetricarboxaldehyde (BT), and 3,3′-dihydroxybenzidine (DH) were used to construct a COF layer. In addition to the conventional preparation method, we increased the ratio of BT and DH to be 1:2.5, and impressively, the morphologies of acquired UC (1:2.5) materials were quite different from the previous reticular structure and gradually extended from the spherical structure to the prickly structure with the increase of COF monomers. Remarkably, all of the UC materials possessed better luminescence properties than individual COF due to the limited COF layers. Meanwhile, UC-1 materials with an optimal COF layer displayed the strongest emission. In comparison with a single COF, the quantum yields of UC-1 and UC-1 (1:2.5) were increased nearly 7 times and 5 times, respectively. Moreover, the fluorescence of UC-1 materials was progressively enhanced via selective F − sensing. This work is expected to shed light on the potential hybridization of MOF−COF with structural adjustment, morphological design, and luminescence enhancement.

ZIF-8@dye@ZIF-8@dye materials with different fluorescence emission in dispersed and solid states were both obtained by tuning the initial encapsulation concentration of dye and changing the structure of the inner and outer ZIF-8@dye layers.

Construction of color-tunable luminescent polymeric materials with enhanced emission intensity and roomtemperature phosphorescence (RTP) performance regulated by a single chromophore component is highly desirable in the scope of photoluminescent materials. Herein, a set of binary copolymers were facilely synthesized using free radical polymerization by selecting different types of polymer matrix and N-substituted naphthalimides (NPA) as chromophores. Surprisingly, the fluorescence emission of copolymers could be remarkably enhanced, because of the intramolecular aggregation of NPA manipulated by a single polymer chain in both solution and solid state. Moreover, RTP signals of binary copolymers were all clearly observed in the air without any processing procedure, because of the embedding of phosphors into hydrogen bonding networks after copolymerization with vinyl-based acrylamide monomers. Taking advantages of the synergistic effect of copolymerization-induced aggregation and copolymerization-induced rigidification to promote optical performance, UV stimulus-responsive luminescent polymer films with processability, flexibility, and adjustable emission wavelength were simply prepared using a drop-casting method in large scale, the setting of which is the basis for application in the fields of organic optoelectronics, information security, and bioimaging/sensing.

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In 2001, Tang et al. reported luminescent organic molecules with aggregation-induced emission (AIE) feature, termed as AIEgen, which exhibiting intensive fluorescence emission in aggregated fashion compared with those in good solvent, providing new strategy to overcome the notorious ACQ effect. [7][8][9] With the 20 years continuous development in AIE, researchers decipher AIE phenomenon by the restriction of intramolecular motions (RIM) rules containing both restriction of intramolecular rotations (RIR) and restriction of intramolecular vibrations (RIV). [10,11] Moreover, in order to fabricate fluorescence materials response to external/internal stimuli, combining AIEgen with supramolecular interactions, such as hydrogen bonding, [12][13][14][15] metal-coordination interactions, [16][17][18][19] π-π stacking interactions, [20][21][22] host-guest interactions, [23][24][25] electrostatic interactions, [26] hydrophobic interactions, [27,28] etc., has proved to be a robust and significant strategy.Macrocyclic hosts involving cyclodextrins, cucurbiturils, crown ethers, calixarenes, and pillararenes are the most popular building blocks for the fabricating of supramolecular fluorescent materials with enhanced emission intensity, uniform morphology, fascinating chemical/physical properties, diverse stimuli-responsive properties, and environment adaptation. [29][30][31][32][33][34][35][36][37] The introduction of host-guest interactions based on pillararenes for the fabrication of supramolecular assemblyinduced emission enhancement (SAIEE) systems are regard as a crucial approach to fabricate supramolecular AIE systems, which was first demonstrated by Yang and co-workers in 2014. [38] In particular, pillar[5]arenes reported by Ogoshi et al. in 2008 was regard as a typical type of macrocycles in the construction of supramolecular luminescent materials due to their a) high binding affinity toward electron-deficient group in organic/ aqueous solution; b) high synthetic yield and simple process for further functionalization; c) symmetrical rigid column structure. [39][40][41][42] For instance, the emission intensity of supramolecular polymer networks constructed by tetraphenylethene Supramolecular assembly-induced emission enhancement (SAIEE) systems have been proved to be a highly efficient approach for the fabrication of luminescent nanoparticles with uniform morphology. Herein, fluorescent supramolecular vesicles are constructed from tetraphenylethene-based cyano-alkane tetramer (TPE-(CN) 4 ) and pincer-like hosts containing two pillar[5]arene units (B-(TAP[5]A) 2 ) through a synergistic effect of host-guest interactions and hydrophobic interactions. Notably, the emission intensity of supramolecular vesicles can be remarkably enhanced with quantum yield determined to be 37.69%, whereas that of TPE-(CN) 4 is only 18.93% in mixture solvent. Furthermore, the supramolecular vesicles can retard the photocyclization reaction of TPE-(CN) 4 under UV light and exhibit considerable emission intensity at high temperature. Enthused ...