Color-Tuned Highly Fluorescent Organic Nanowires/Nanofabrics: Easy Massive Fabrication and Molecular Structural Origin

Abstract

The development of one-dimensional fluorescent nanowires (1D-NWs) and their higher-dimensional architectures such as nanowebs and nanofabrics (2D-NFs) could open a new area in nanomaterials science and nanotechnology. In particular, fluorescent pi-electronic 1D-NWs are considered promising materials for realizing innovative nanodevices together with semiconductors and metallic NWs. We earlier reported that 1-cyano-trans-1,2-bis-(3',5'-bis-trifluoromethyl-biphenyl)ethylene (CN-TFMBE), a simple but very peculiar derivative of oligo(p-phenylene vinylene)s (OPV) composed of a cyano-stilbene backbone, self-assembles easily into 1D-NWs with highly enhanced fluorescence emission in the solid state. We report herein surprising new outcomes obtained from a more detailed exploration of the self-association behavior of CN-TFMBE and its analogues. We found that CN-TFMBE self-assembled into highly fluorescent 1D-NWs and 2-D NFs very easily and massively, irrespective of whether drop casting, spin coating, or vacuum deposition was used for processing. However, we additionally found that, if the backbone cyano group or trifluoromethyl substituents were removed from CN-TFMBE, the resulting molecule did not form 1D-NWs under any conditions. Through structural analyses using mid- and wide-angle X-ray diffraction methods and multiscale computer simulation techniques, we formulated molecular structural guidelines for programming pi-electron molecules into highly fluorescent 1D-NWs and 2-D NFs. Interestingly, we demonstrated that R,G,B,Y-color tuned 1D-NWs and NFs could be easily and massively fabricated based on our guidelines. This class of highly fluorescent color-tuned organic pi-electronic nanomaterial is expected to open a new phase in applications such as nanoscale optoelectronics, sensing, and biological devices.

Tunable self-assembly of Irinotecan-fatty acid prodrugs with increased cytotoxicity to cancer cells

“…The SN38 moiety of Irinotecan is a highly rigid planar structure, which allows the growth of nanoparticles in one direction. 34 Irinotecan is hydrophilic and cannot form aggregates in water. Coupling of valeric acid (C5) with Irinotecan enhances the lipophilicity and induces the aggregation of Iri-5C in water, but the alkyl chain is too short to affect the direction of growth determined by the SN38 moiety.…”

p-Carboxyl-N-salicylideneanilines: Simple but efficient chromophores for one-dimensional microrods with aggregation-induced emission enhancement (AIEE) characteristics

“…To investigate the effect of fabrication conditions on the formation of pCSA into 1D microrods, we also studied the fabrication method of solvent evaporation besides recrysallization [17]. As compared in Fig.…”

“…In particular, one-dimensional (1D) microstructured materials are expected to have distinct advantages as building blocks for miniaturized devices [13][14][15][16]. However, synthesis and preparation methods for reported 1D organic materials are usually complicated [17][18][19][20][21]; furthermore, due to the concentration-quenching effect for most organic fluorophores, fluorescence quantum yields of compounds with intensive emission in solution state would become much lower in their aggregate/solid state [22,23]. Therefore, improvements in 1D fluorescent organic materials with both simple preparing method and high quantum yields are still challenging.…”

Blue‐Emitting Nanocrystals, Microcrystals, and Highly Oriented Nanofibers Prepared by Reprecipitation and Solvent Drop‐Casting of 2‐Phenyl‐naphthoxazoles

“…Various tactics have been imagined to solve this problem, [5] for example selecting molecules that form J-aggregates, [6] constructing nonplanar structures, 7 or introducing bulky groups [7][8][9] and ions [10] to modify the molecular arrangement of the fluorophores in the solid state. These approaches often resulted in highly efficient photoluminescent materials and culminated with the concept of aggregation-induced emission [11] that recently opened a new field of exciting research.…”