Poly(3-hexylthiophene) Based Block Copolymers Prepared by “Click” Chemistry

Abstract

π-Conjugated block copolymers have been prepared from terminal azide functionalized polystyrenes (PS) and alkyne functionalized poly(3-hexylthiophene)s (P3HT) via a copper(I) catalyzed Huisgen [3 + 2] dipolar cycloaddition reaction. The functionalized α-azido-PS homopolymer was prepared by atom transfer radical polymerization from a specifically designed initiator bearing the azide function, whereas ω-ethynyl-P3HT and α,ω-pentynyl-P3HT were synthesized by a modified Grignard metathesis polymerization using alkynyl Grignard derivatives. The electronic environment of the alkynyl end groups was shown to be decisive in determining triazole ring formation.

Block copolymer strategies for solar cell technology

“…However, the use of coupling steps can prove troublesome when they are not quantitative, which is often the case when working with macromolecules with only one distinct functional group on each chain that is available for reaction. Consequently, a step growth-like approach requires highly efficient coupling chemistry, such as click chemistry, 120 otherwise the eventual yield of the block copolymers will be low. [121][122][123] Clearly, low yield of the final active block copolymer puts serious doubt on their industrial viability.…”

A New Supramolecular Route for Using Rod‐Coil Block Copolymers in Photovoltaic Applications

“…[14][15][16][17][18][19] Block copolymers composed of an electron-donating and an electronaccepting block are therefore particularly interesting for PV applications and are presently studied worldwide by several research groups. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] Particularly, rod-coil block copolymers using poly[(2,5-di(2-ethyl)hexyloxy)-1,4-phenylenevinylene] (DEH-PPV) as electron donor and various coil blocks (such as polystyrene or polybutylacrylate) with covalently linked fullerene moieties as electron acceptor have been investigated intensively. [23][24][25][26][27][28] Although these studies have given considerable insight into the physics of copolymer self-assembly, their efficient utilization as the active layer in PV devices has not yet been fully demonstrated.…”

Simultaneous morphological stability and high charge carrier mobilities in donor-acceptor block copolymer/PCBM blends

“…A classical approach is to blend small amounts of a relevant BCP into the P3HT:PCBM blend of optimum composition in order to improve the stability. 19,[28][29][30][31][32][33] However, this approach did not deliver the desired morphological effect in particular at high temperatures or upon prolonged annealing. 19,32 Therefore, we have studied the charge transport in OFETs of a P3HT:PCBM blend with an optimized composition of 1:0.8 (wt:wt) 57 in comparison with a BCP:PCBM 5 60:40 blend.…”

“…[23][24][25] In consequence, several strategies have been developed to stabilize the blend nanomorphology toward enhanced long-term stability, for example, by crosslinking of either donor or acceptor material, 26 increasing the glass transition temperature, 27 or by compatibilization of the blend using small amounts of block copolymers (BCPs). 19,[28][29][30][31][32][33] Several reports on BCP-stabilized polymer:fullerene blends demonstrate the improved but still limited morphological stability and only a partial suppression of PCBM crystallization. 19,32,34 Here, donor-acceptor BCPs are attractive candidates as single material since they can self-assemble into well-defined nanoscale BHJ morphologies which are in a stable thermodynamic equilibrium.…”