Rod–coil and all-conjugated block copolymers for photovoltaic applications

Enhancing the thermal stability of the bulk-heterojunction photovoltaics based on P3HT/PCBM by incorporating diblock amphipathic P3HT–PEO at D/A interface

A diblock amphipathic copolymer P3HT–PEO was rationally designed and easily synthesized.

Ultra-large sheet formation by 1D to 2D hierarchical self-assembly of a “rod–coil” graft copolymer with a polyphenylene backbone

This study presents a unique ultra-large sheet formation through 1D to 2D hierarchical self-assembly of a rod–coil graft copolymer containing a rigid polyphenylene backbone tethered with flexible poly(ethylene oxide) side chains.

A donor–acceptor conjugated block copolymer of poly(arylenevinylene)s by ring-opening metathesis polymerization

A donor–acceptor conjugated block copolymer of poly(arylenevinylene)s has been synthesized by ring-opening metathesis polymerization.

Ultrafast RAFT polymerization: multiblock copolymers within minutes

A remarkably efficient and versatile procedure for the preparation of multiblock copolymers is presented.

Air-liquid interfacial self-assembly of conjugated block copolymers into ordered nanowire arrays

The ability to control the molecular packing and nanoscale morphology of conjugated polymers is important for many of their applications. Here, we report the fabrication of well-ordered nanoarrays of conjugated polymers, based on the self-assembly of conjugated block copolymers at the air-liquid interface. We demonstrate that the self-assembly of poly(3-hexylthiophene)-block-poly(ethylene glycol) (P3HT-b-PEG) at the air-water interface leads to large-area free-standing films of well-aligned P3HT nanowires. Block copolymers with high P3HT contents (82-91%) formed well-ordered nanoarrays at the interface. The fluidic nature of the interface, block copolymer architecture, and rigid nature of P3HT were necessary for the formation of well-ordered nanostructures. The free-standing films formed at the interface can be readily transferred to arbitrary solid substrates. The P3HT-b-PEG films are integrated in field-effect transistors and show orders of magnitude higher charge carrier mobility than spin-cast films, demonstrating that the air-liquid interfacial self-assembly is an effective thin film fabrication tool for conjugated block copolymers.

Role of block copolymer morphology on particle percolation of polymer nanocomposites

In this study, the effects of nanoparticle volume fraction, block stiffness, and diblock composition on the microstructure and electrical properties of composites are investigated using molecular dynamics simulation. It is shown that selective localization of conductive nanoparticles in a continuous block of diblock copolymer can dramatically reduce the percolation threshold. In the flexible-flexible copolymer systems with a relatively low particle loading, as the ratio of two blocks varies, one sees four kinds of phase structure: signal continuous, lamellar, co-continuous, and dispersed, corresponding to the order-disorder and continuity-dispersion transitions. In consideration of particle connectivity, the best electrical performance can be achieved with a special tri-continuous microstructure. While in the semi-flexible systems, the existence of rigid blocks can destroy the lamellar structure. If particles are located in the flexible block, a moderate stiffness of the rigid block can extensively enlarge the tri-continuous region, and high conductivity can be realized over a wide range of diblock compositions. If particles are located in the rigid block, however, high conductivity only emerges in a narrow composition range. In addition, the block should be prevented from becoming overstiff because this will cause direct particle aggregation.

Donor-Acceptor Block Copolymers: Synthesis and Solar Cell Applications

Fullerene derivatives have been widely used for conventional acceptor materials in organic photovoltaics (OPVs) because of their high electron mobility. However, there are also considerable drawbacks for use in OPVs, such as negligible light absorption in the visible-near-IR regions, less compatibility with donor polymeric materials and high cost for synthesis and purification. Therefore, the investigation of non-fullerene acceptor materials that can potentially replace fullerene derivatives in OPVs is increasingly necessary, which gives rise to the possibility of fabricating all-polymer (polymer/polymer) solar cells that can deliver higher performance and that are potentially cheaper than fullerene-based OPVs. Recently, considerable attention has been paid to donor-acceptor (D-A) block copolymers, because of their promising applications as fullerene alternative materials in all-polymer solar cells. However, the synthesis of D-A block copolymers is still a challenge, and therefore, the establishment of an efficient synthetic method is now essential. This review highlights the recent advances in D-A block copolymers synthesis and their applications in all-polymer solar cells.

All-conjugated cationic copolythiophene “rod–rod” block copolyelectrolytes: synthesis, optical properties and solvent-dependent assembly

The optical and thermal properties and solvent-dependent assembly of all-conjugated cationic copolythiophene block copolyelectrolytes are investigated.

Monotelechelic poly(p-phenylenevinylene)s by ring opening metathesis polymerisation

High molecular weight poly(p-phenylenevinylene)s with a single reactive end group are reported that act as excellent macroinitiators in block copolymer synthesis.

25th anniversary article: no assembly required: recent advances in fully conjugated block copolymers

Fully conjugated block copolymers have emerged as promising materials that combine semiconducting properties with the ability to self-assemble at the nanoscale. The convergence of these two features has tremendous implications for a number of fundamental molecular assembly and transport questions, while also offering unique advantages for a variety of applications. For example, a nanostructured active layer in organic photovoltaic (OPV) devices may provide for efficient charge separation while simultaneously affording continuous, unimpeded pathways for charge carriers to migrate to their respective electrodes within each individual microphase. This review details the recent progress made in the preparation and application of fully conjugated block copolymers and serves as a comprehensive reference for the materials that have been reported in the literature to date. Focus is placed on fully conjugated block copolymers prepared using chemistries that are relevant to high-performance polymers in organic electronics research, for example Stille, Suzuki-Miyaura, and Yamamoto coupling.