Direct Formation of Large-Area 2D Nanosheets from Fluorescent Semiconducting Homopolymer with Orthorhombic Crystalline Orientation

Abstract

Semiconducting polymers have been widely investigated due to their intriguing optoelectronic properties and their high crystallinity that provides a strong driving force for self-assembly. Although there are various reports of successful self-assembly of nanostructures using semiconducting polymers, direct in situ self-assembly of these polymers into two-dimensional (2D) nanostructures has proven difficult, despite their importance for optoelectronics applications. Here, we report the synthesis of a simple conjugated homopolymer by living cyclopolymerization of a 1,6-heptadiyne (having a fluorene moiety) and its efficient in situ formation of large-area 2D fluorescent semiconducting nanostructures. Using high-resolution imaging tools such as atomic force microscopy and transmission electron microscopy, we observed the solvent-dependent self-assembly behaviors of this homopolymer; the identical starting polymer formed 2D nanosheets with different shapes, such as rectangle, raft, and leaf, when dissolved in different solvents. Furthermore, super-resolution optical microscopy enabled the real-time imaging of the fluorescent 2D nanosheets, revealing their stable and uniform shapes, fluorescence, and solution dynamics. Notably, we propose an orthorhombic crystalline packing model to explain the direct formation of 2D nanostructures based on various diffraction patterns, providing important insight for their shape modulation during the self-assembly.

Molecular Control of Internal Crystallization and Photocatalytic Function in Supramolecular Nanostructures

“…12,13 Examples with differences as small as a single carbon 14 or an isomeric linkage 15 used have been previously demonstrated. When working with chromophore assemblies that possess highly ordered crystalline domains, 16–20 it should also be possible to control the crystal packing through slight modifications to the supramolecular monomers, an effect which has already been documented for organic single crystals, 21–23 and self-assembled monolayers. 24 …”

Rapid formation and real-time observation of micron-sized conjugated nanofibers with tunable lengths and widths in 20 minutes by living crystallization-driven self-assembly

“…[35][36][37] For the spontaneous formation of the conjugated nanoparticles, we have developed another strategy termed In situ Nanoparticlization of Conjugated Polymers (INCP). [38][39][40][41][42] INCP is a process whereby insoluble conjugated polymers are intentionally introduced as the second block. During the synthesis of BCPs, the strong p-p interaction induces spontaneous nanoparticlization, producing semiconducting nanostructures without post-treatment.…”

Catalytic living ring-opening metathesis polymerization with Grubbs’ second- and third-generation catalysts

“…Over the past decade, a variety of methods for the preparation of mono and bis-end-functional (telechelic) ROMP polymers have been developed [23][24][25][26][27] . ROMP polymers have also been prepared for biological/medicinal applications [28][29][30] , electronics [31][32][33] , battery separators 34 , anion exchange membranes 35 and many others.…”