Brush Polymer of Donor-Accepter Dyads via Adduct Formation between Lewis Base Polymer Donor and All Carbon Lewis Acid Acceptor

Abstract

A synthetic method that taps into the facile Lewis base (LB)→Lewis acid (LA) adduct forming reaction between the semiconducting polymeric LB and all carbon LA C60 for the construction of covalently linked donor-acceptor dyads and brush polymer of dyads is reported. The polymeric LB is built on poly(3-hexylthiophene) (P3HT) macromers containing either an alkyl or vinyl imidazolium end group that can be readily converted into the N-heterocyclic carbene (NHC) LB site, while the brush polymer architecture is conveniently constructed via radical polymerization of the macromer P3HT with the vinyl imidazolium chain end. Simply mixing of such donor polymeric LB with C60 rapidly creates linked P3HT-C60 dyads and brush polymer of dyads in which C60 is covalently linked to the NHC junction connecting the vinyl polymer main chain and the brush P3HT side chains. Thermal behaviors, electronic absorption and emission properties of the resulting P3HT-C60 dyads and brush polymer of dyads have been investigated. The results show that a change of the topology of the P3HT-C60 dyad from linear to brush architecture enhances the crystallinity and Tm of the P3HT domain and, along with other findings, they indicate that the brush polymer architecture of donor-acceptor domains provides a promising approach to improve performances of polymer-based solar cells.

Polymerization of Polar Monomers Mediated by Main-Group Lewis Acid–Base Pairs

“…In some cases, the employment of all organic LPs, such as B­(C 6 F 5 ) 3 /PR 3 (NHC or amine) ,,, and Me 3 SiNTf 2 /PR 3 for the polymerizations of acrylates, B­(C 6 F 5 ) 3 /DABCO for the epimerization of meso -LA to rac -LA, Fmes 2 BF/aniline for the ROP of NCA, and BEt 3 /LB for the copolymerization of CO 2 (COS) with epoxides, ,, has been characterized as a “green” and/or “sustainable” synthesis of metal-free polymeric materials. (5) Advancing materials chemistry by applying the principles of the LPP and LP chemistry as a new platform, as demonstrated by highlighted examples such as the development of a new type of reversible/dynamic cross-linking system that can be reshaped, reprocessed, or repaired, and has also been exploited in stimulus-responsive and self-healing materials, , the construction of a novel gelator with a more specific and triggerable response, and the utilization of LPP for novel polymer compositions and architectures relevant to organic photovoltaic applications. ,, …”

“…The same group recently designed and synthesized the linked D−A dyad P3HT-(CH 2 ) 3 -MIM-C 60 [Scheme 58B; P3HT = poly(3-hexylthiophene)] and brush polymer of dyads P[P3HT-(CH 2 ) 3 -VIM-C 60 ] (Scheme 58C), via a facile "click"-type LB−LA adduct forming approach (Scheme 59). 465 The authors found that a change of the topology of the P3HT-C 60 dyad from a linear to brush architecture enhanced the crystallinity and T m of the P3HT domain, and interestingly, covalently linked D−A dyads showed an extended lightharvesting wavelength range of the active layer and increased generation efficiency of the excitons of the semiconducting polymer, when compared with control systems where C 60 is either absent or unlinked. These interesting findings should provide a promising approach to control the morphology of the D/A active layer in organic photovoltaic applications.…”

“…( 5) Advancing materials chemistry by applying the principles of the LPP and LP chemistry as a new platform, as demonstrated by highlighted examples such as the development of a new type of reversible/dynamic cross-linking system that can be reshaped, reprocessed, or repaired, and has also been exploited in stimulus-responsive and self-healing materials, 466,467 the construction of a novel gelator with a more specific and triggerable response, 468 and the utilization of LPP for novel polymer compositions and architectures relevant to organic photovoltaic applications. 464,465,469 Since the submission of this manuscript, contributions to the LPP area continued to emerge. For example, McGraw and Chen disclosed that MeAl(BHT) 2 /NHC (or NHO) LPs promoted effective polymerization of biorenewable methyl crotonate to high-MW polymers, while NHCs alone only led to dimerization.…”

Lewis Pair Polymerization for New Reactivity and Structure in Polymer Synthesis

“…Chen’s team demonstrated that poly(3-hexylthiophene) macromer anchored with alkyl or vinyl imidazolium end groups can be readily converted into a polymeric NHC Lewis base that is capable of binding to Lewis acidic C 60 to form a single donor-acceptor dyad or brush of donor-acceptor dyads. The special architecture of brush donor-acceptor dyads provides promising potential applications in polymer-based solar cells [ 13 ]. In a different way, Jäkle and co-workers reported the interaction pattern between a polymeric Lewis acid and a telechelic Lewis base [ 14 ].…”