Hyperbranched Microwire Networks of Organic Cocrystals with Optical Waveguiding and Light‐Harvesting Abilities

Abstract

We report the synthesis of hyperbranched organic microwire (MW) networks comprising 1,4‐bis(pentafluorostyryl)benzene (10Ft) and 9,10‐bis(phenylethynyl)anthracene (BA) using a simple solution co‐assembly route. Pure 10Ft or BA assemblies cannot produce such complex MW networks; in contrast with a binary cocrystal of 10Ft and BA with a 2:1 molar ratio ((2:1)10Ft:BA), which is formed via intermolecular arene‐perfluoroarene (AP) interactions. A new generation of multiple MWs grow epitaxially on the previous generation of MWs to form MW arrays in which BA may also act as an intermediate product to facilitate the regeneration of (2:1)10Ft:BA. Highly aligned and well‐connected MW networks enable superior optical waveguiding ability. Moreover, a red‐emitting dopant, 5,12‐bis(phenylethynyl)naphthacene (BN) was incorporated into (2:1)10Ft:BA host MWs, giving light‐harvesting hierarchical MW networks via an energy‐transfer (ET) process. The realization of the hyperbranched MWs provides us with deep insight into the rational creation of complex branched arrays from functional organic cocrystals.

Torsional disorder and planarization dynamics: 9,10-bis(phenylethynyl)anthracene as a case study

“…[29][30][31][32] Herein, we present our investigation of the torsional dynamics of 9,10-bis(phenylethynyl)anthracene (BPEA, Figure 1A) in both the lowest singlet excited state and the ground state in liquids of different viscosity as well as in polymers, using a combination of fs broadband transient absorption (TA) and fluorescence up-conversion spectroscopy (FLUPS). BPEA is characterised by a high fluorescence quantum yield and is widely used as emitter in chemiluminescence, 33,34 luminescent molecular liquids, 35 optoelectronics, [36][37][38] sensors, 39 triplet-triplet annihilation up-conversion, [40][41][42] and more recently as dye for singlet fission. [43][44][45] In solution, the S 1 -S 0 absorption and emission bands of BPEA do not exhibit mirror-image relationship: the absorption band is broad and structureless, whereas the emission band is structured.…”

Directional Self-Assembly of Facet-Aligned Organic Hierarchical Super-Heterostructures for Spatially Resolved Photonic Barcodes

“…38,39 However, micro-/nanoscale materials are generally formed as dispersed or random colloidal particles, thus making it difficult to exert orientational control on these particles. 40 Up to now, strategies to achieve oriented superstructures often rely on emulating the particles with surface patches or the application of external fields, 41−44 whereby the particle blocks featuring identified interactions could spontaneously assemble into ordered architectures. However, these methods generally suffer from a complicated structure design and inaccurate orientation of the mutual particles, thus restricting the effective construction of highquality photonic barcodes.…”

“…Compared with a molecular self-assembly, a micro-/nanoscale particle self-assembly affords an opportunity to precisely arrange multiple organic heterostructure blocks into well-defined hierarchical super-heterostructures. − Such super-heterostructures would integrate multiple spatial segments into a single architecture, thus containing abundant encoding elements and dramatically increasing the encoding capacity. , However, micro-/nanoscale materials are generally formed as dispersed or random colloidal particles, thus making it difficult to exert orientational control on these particles . Up to now, strategies to achieve oriented superstructures often rely on emulating the particles with surface patches or the application of external fields, − whereby the particle blocks featuring identified interactions could spontaneously assemble into ordered architectures.…”

Fractal Branched Microwires of Organic Semiconductor with Controlled Branching and Low-Threshold Amplified Spontaneous Emission

“…Of note is that such intricate fractal patterns were formed without the use of any foreign catalyst or intermediate, in sharp contrast to their inorganic and organic cocrystal analogues. [4][5][6][7][8][9][10][11][12]33 Moreover, binary cocrystal MWs comprising 1,4-bis(pentafluorostyryl)benzene (10Ft) and 9,10- Notably, OPV-A solutions exhibit solvent-dependent optical properties (Figure S15) and its photoluminescence (PL) spectrum in 1,4-dioxane exhibits a main PL peak at 484 nm (Figure 2e) that corresponds to cyan light (inset in Figure 2e). Unlike that of β-OPV-A MRs centered at 502 nm (Figure S5b), PL spectra of α-OPV-A MWs with and without branching have nearly identical profiles with a dominant PL band at 528 nm (Figure 2f).…”

“…The transition in preferential facets facilitates the realization of fractal branching MWs, affected by specific growth pathways. Of note is that such intricate fractal patterns were formed without the use of any foreign catalyst or intermediate, in sharp contrast to their inorganic and organic cocrystal analogues. − , Moreover, binary cocrystal MWs comprising 1,4-bis­(pentafluorostyryl)­benzene (10Ft) and 9,10-bis­(phenylethynyl)­anthracene (BA) exhibit solvent-independent branching growth, while α-OPV-A crystallizes in various architectures upon changing the solvents (Figures S10 and S11). Additionally, β-OPV-A and unmethylated OPV-A (abbreviated OPV-B) cannot assemble into fractal MWs even on varying the crystallization conditions (Figures S12–S14).…”