Programmable Assembly of π‐Conjugated Polymers

Abstract

resulting in device efficiencies exceeding 18%. [11] Applications for π-conjugated polymers requiring high conductivity are also being widely explored, most notably using highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) in fields such as energy storage, tissue engineering, and textile-based electronics. [12][13][14][15][16] Applying π-conjugated polymers in electronics requires the complimentary development of favorable optoelectrical and mechanical properties. Molecular orbital alignments and polymer crystallization are of paramount importance. These interactions impact numerous properties, such as the polymer band energies, [17] charge-transfer processes, [18] redox potentials, [19] and photophysics. [20,21] Close chain-packing facilitates interpolymer charge transport, improving charge mobility in polymers as charges move by a hopping mechanism. [22] Additionally, the nanoscale morphology has a strong impact on the efficiency of photophysical processes, including exciton diffusion and dissociation, which are vital for OPVs and OPCs. [23] For wearable electronics flexibility and stretchability must also be considered. The brittle nature of crystalline materials produced from π-conjugated polymers is one of the major challenges that remains to be solved. The highly crystalline ordering caused by strong noncovalent interactions, chain interdigitation, or rigid polymer backbones leads to high tensile moduli and low stress loadings. [24] Many approaches have been explored to overcome this challenge including copolymerizing or blending conjugated polymers with elastomers and forming gels. [25][26][27][28][29] Programmed assembly (Figure 1) is an emerging bridge between our understanding of morphological ordering and functional materials. Programming order means to intentionally control ordering and morphology through inputs to achieve a desired functionality. It is a tool for rational material design, enabling structural complexity via a bottom-up approach to combine and enhance desirable material properties. This complexity results from orthogonal chemistries, which can be activated sequentially to build up structures in a stepwise manner. By this approach, each function would be met with its appropriate structure, as a morphology is selected to in order to achieve well-defined properties.Herein, we provide a review of innovative efforts being explored to program order in π-conjugated polymers from the π-Conjugated polymers have numerous applications due to their advantageous optoelectronic and mechanical properties. These properties depend intrinsically on polymer ordering, including crystallinity, orientation, morphology, domain size, and π-π interactions. Programming, or deliberately controlling the composition and ordering of π-conjugated polymers by well-defined inputs, is a key facet in the development of organic electronics. Here, π-conjugated programming is described at each stage of material development, stressing the links between each programming mode. Covalent programming is performed during p...

Efficient and Controlled Seeded Growth of Poly(3-hexylthiophene) Block Copolymer Nanofibers through Suppression of Homogeneous Nucleation

“…The extension of the living CDSA seeded-growth method to crystallizable π-conjugated polymeric materials has provided a particularly attractive route to functional 1D and 2D nanoparticles with applications in optoelectronics. , For example, photoisomerization of a BCP with a poly­(phenylene vinylene) (PPV) core-forming block from the as-synthesized, noncrystallizable cis isomer to the crystallizable trans configuration on irradiation with light in the presence of seeds has been shown to yield BCP nanofibers of controlled length, in addition to more complex 1D architectures such as segmented and gradient comicelles . In addition, the oxidation-promoted self-assembly of a BCP with a crystallizable polytellurophene core-forming block was exploited to provide stimuli-responsive fibers that switch between assembled and disassembled states with the addition of oxidants and reductants .…”

Thiophene α-Chain-End-Functionalized Oligo(2-methyl-2-oxazoline) as Precursor Amphiphilic Macromonomer for Grafted Conjugated Oligomers/Polymers and as a Multifunctional Material with Relevant Properties for Biomedical Applications

“…From this point of view, the architecture of g-CPs is an alternative “full of options” for many types of applications because it allows control of the processing–structure–properties relationship from the molecular design stage, when self-assembly can be programmed and structurally optimized [ 51 , 52 ].…”

A Short Review on Surface‐Confined Monolayers of π‐Conjugated Polymers for Photovoltaics

“…[ 41 ] As a result, great efforts have been devoted to investigate the controlled formation of the desired micro‐/nanostructure of CPs for PV applications. [ 36,42–45 ]…”

“…It has been widely accepted that the performance of CP-based devices is significantly influenced by the micro-/nanostructure in bulk or in the thin film of CPs, which intrinsically depends on polymer ordering, including crystallinity, orientation, domain size, and π-π interactions. [35][36][37] The diverse functional groups in CPs can modulate the film morphology in both bulk and interfaces [38] and adjust the work function of the metal or metal oxide electrodes. [39,40] The 3D structure of CPs enables them to be the template for the fabrication of mesoporous electrode materials.…”

“…[41] As a result, great efforts have been devoted to investigate the controlled formation of the desired micro-/nanostructure of CPs for PV applications. [36,[42][43][44][45] In addition to the intrinsic structure-property effect, filmforming techniques are probably the most important factors that influence the morphology and performance of polymer films. Conventional strategies such as spin coating (SP), [46][47][48][49] casting, [50,51] printing, [52][53][54] doctor blading, [55,56] et al are commonly used to prepare organic molecule-coated surfaces.…”