Interfacial Crystallization‐Driven Assembly of Conjugated Polymers/Quantum Dots into Coaxial Hybrid Nanowires: Elucidation of Conjugated Polymer Arrangements by Electron Tomography

Abstract

A simple and practical “solution‐biphase method” allows the preparation of efficient charge‐transporting 1D nanocrystals with coaxial p–n junctions. It involves gradual diffusion of a top layer of poor solvent (acetonitrile) into a bottom layer of poly(3‐hexyl thiophene)‐b‐poly(2‐vinyl pyridine) (P3HT‐b‐P2VP) conjugated polymers (CPs) and CdSe quantum dots (QDs) dissolved in chloroform. Initial interfacial crystallization‐driven assembly of CPs results in the formation of seeds consisting of dimeric QDs transversely bridged by CPs. Coaxial CPs/QDs hybrid NWs are generated by 1D growth of QDs‐dimeric seeds, enabling tracing of the CPs‐crystallization process via the QDs. Thus, well‐arranged QDs along the longitudinal axis of the NWs infer highly crystalline CPs with edge‐on orientation, as confirmed by electron tomography, UV–vis spectroscopy, and grazing‐incidence wide‐angle X‐ray scattering. This high cristallinity as well as the increased length of the resulting hybrid NWs in solution and the corresponding crystallite size in as‐cast film represent a significant improvement compared to the conventional “one‐pot addition method”. Moreover, although randomly QDs‐attached hybrids of P3HT homopolymer are produced by the solution‐biphase method, branched aggregates with micrometer‐long NW arms are generated from the crystal seeds containing multiple growth facets without precipitate, despite acetonitrile being a nonsolvent.

Uniform electroactive fibre-like micelle nanowires for organic electronics

“…The resulting nanostructures show colloidal stability due to the presence of the solvent swollen corona and have been exploited for a variety of uses including the delivery of therapeutic cargoes in nanomedicine 2 , as additives for friction reduction 3 , fillers for composite reinforcement 4 or for the formation of nanoscopic arrays using optical tweezers 5 . However, although recent advances have described examples of fibre-like micelles with novel photophysical characteristics 6 7 , their assembly into complex semiconducting particles, bundles and branched superstructures 8 9 10 11 , and their fabrication of coaxial nanowires with quantum dots 12 13 , ordered two-dimensional assemblies at interfaces 14 and solar cells 15 , the evaluation of their potential as functional electroactive materials in devices is virtually unexplored 14 15 ; specifically, uniform samples of low length dispersity have not been investigated.…”

50th Anniversary Perspective: Functional Nanoparticles from the Solution Self-Assembly of Block Copolymers

“…N-type quantum dots or fullerenes and p-type P3HT-containing BCPs have been used to form hybrid nanowires by solution processing routes. [256][257][258] 6.5 Applications of BCP micelles for lubrication and composite reinforcement, and as stabilizers.…”

Highly crystalline and uniform conjugated polymer thin films by a water-based biphasic dip-coating technique minimizing the use of halogenated solvents for transistor applications

“…During the dip-coating process, the solvent properties of the top phase solution strongly affected the resulting lm formation as well as the crystallization behavior of the conjugated polymer. 27,28 The solvent evaporation rate is one of the most critical factors controlling the crystallinity of a polymer lm prepared by dip coating. A high boiling point solvent can facilitate crystallization among polymer chains by prolonging the solvent evaporation time.…”

“…Numerous studies have reported that solvent additive-assisted solution processes can perform better than systems prepared without a solvent additive. 27,34,35 We tested solvent additives in the biphasic dip-coating method in two different ways ( Fig. 2b): (1) by oating the solvent additive on a polymer-dissolving top-phase solution (oating method); and (2) by mixing the solvent additive with the polymerdissolving solution before forming a biphasic system (mixing method).…”