All-Conjugated Block Copolymers

Abstract

All-conjugated block copolymers of the rod-rod type came into the focus of interest because of their unique and attractive combination of nanostructure formation and electronic activity. Potential applications in a next generation of organic polymer materials for photovoltaic devices ("bulk heterojunction"-type solar cells) or (bio)sensors have been proposed. Combining the fascinating self-assembly properties of block copolymers with the active electronic and/or optical function of conjugated polymers in all-conjugated block copolymers is, therefore, a very challenging goal of synthetic polymer chemistry. First examples of such all-conjugated block copolymers from a couple of research groups all over the world demonstrate possible synthetic approaches and the rich application potential in electronic devices. A crucial point in such a development of novel polymer materials is a rational control over their nanostructure formation. All-conjugated di- or triblock copolymers may allow for an organization of the copolymer materials into large-area ordered arrays with a length scale of nanostructure formation of the order of the exciton diffusion length of organic semiconductors (typically ca. 10 nm). Especially for amphiphilic, all-conjugated copolymers the formation of well-defined supramolecular structures (vesicles) has been observed. However, intense further research is necessary toward tailor-made, all-conjugated block copolymers for specific applications. The search for optimized block copolymer materials should consider the electronic as well as the morphological (self-assembly) properties.

Block copolymer strategies for solar cell technology

“…Detailed discussion of the synthesis, self-assembling behavior and applications of rod-based block copolymers can be found elsewhere. [37][38][39]105,109 When rod-based block copolymers are extensively annealed, long range order is commonly observed in the form of nanowires or fibrils. [110][111][112][113] The individual wires consist of aligned rod blocks and have been shown to be particularly valuable for charge mobility.…”

Role of Solution Structure in Self-Assembly of Conjugated Block Copolymer Thin Films

“…This goal has been met by BCPs where either one block has a conjugated backbone and the other has an insulating backbone with pendant conjugated molecules, [29][30][31][32][33][34][35][36][37] or by structures where both blocks have conjugated backbones (CBCPs). [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] Because of the relative stiffness of conjugated backbones, the phase separation of their BCP is complex due to energetic interactions between blocks, the volume fraction of the blocks, and potential crystallization.…”

Poly(3‐hexylthiophene)‐b‐poly(3‐cyclohexylthiophene): Synthesis, microphase separation, thin film transistors, and photovoltaic applications

“…INTRODUCTION Multicomponent-conjugated polymer systems, especially polymer blends [1][2][3][4][5][6][7] and block copolymers, [8][9][10][11][12][13][14][15][16][17][18][19][20] offer the opportunity to tailor their electronic and optical properties to levels well beyond those possible in homopolymers and random/alternating copolymers. Most polythiophene-based multicomponent conjugated polymer systems investigated so far have been based on poly(3-hexylthiophene) (P3HT), 1,27,28 which is known to be a high mobility p-type polymer semiconductor 29,30 and a good donor component in fullerene-based bulk heterojunction (BHJ) solar cells.…”