Reducing the Exciton Binding Energy of Donor–Acceptor‐Based Conjugated Polymers to Promote Charge‐Induced Reactions

Abstract

Exciton binding energy has been regarded as a crucial parameter for mediating charge separation in polymeric photocatalysts. Minimizing the exciton binding energy of the polymers can increase the yield of charge‐carrier generation and thus improve the photocatalytic activities, but the realization of this approach remains a great challenge. Herein, a series of linear donor–acceptor conjugated polymers has been developed to minimize the exciton binding energy by modulating the charge‐transfer pathway. The results reveal that the reduced energy loss of the charge‐transfer state can facilitate the electron transfer from donor to acceptor, and thus, more electrons are ready for subsequent reduction reactions. The optimized polymer, FSO‐FS, exhibits a remarkable photochemical performance under visible light irradiation.

Enormous Promotion of Photocatalytic Activity through the Use of Near-Single Layer Covalent Organic Frameworks

“…However, most of COFs show mediocre activity in photocatalytic H 2 evolution (PHE) compared with traditional inorganic semiconductors, which is mainly related to the difficulty in dissociation of excitons and the rapid recombination of photogenerated electrons and holes during photocatalytic process. 19 Several strategies have been developed to improve the charge separation efficiency of COFs, for example incorporating donor-acceptor (D-A) moieties 20,21 or halogen atoms in COFs, 22,23 constructing novel πconjugated building blocks, 24 and generating junctions with other semiconductors. 25 In addition to the above strategies, reducing the particle size of COFs to nanometer scale is a more facile method to improve the charge separation efficiency due to the possibility of charge carrier recombination is reduced in the short diffusion distance 26 .…”

Enhanced CO2 Photoreduction through Spontaneous Charge Separation in End‐Capping Assembly of Heterostructured Covalent‐Organic Frameworks

“…The results indicate that the E b (41.2 meV) of TMBen is the largest among these samples. Notably, the E b (20.9 meV) of TMBen‐Perylene is significantly lower than that of TMBen‐Anthracene (38.1 meV) and TMBen‐Pyrene (34.6 meV) (Figure S21)), signifying a less energy loss in the charge migration process as well as more charge delocalization in TMBen‐Perylene [38] . Meanwhile, these observations indicate that the modified TMBens contribute to minimizing exciton binding energy through the construction of heterostructure, and thereby facilitating the charge transfer.…”

Excitonic Effects in Polymeric Photocatalysts

“…[68] Ther eduction of exciton binding energy can also promote exciton dissociation in the system, which have been recently achieved by constructing donor-acceptor-based structure. [69] In addition, extrinsic heterostructures (such as,t he mostly well-known noble metal-based co-catalysts) are usually employed, where the contained interfaces serve as reactive areas for boosting exciton dissociation into free charge carriers (Figure 3d). [35] Kosco et al reported the construction of heterojunction nanoparticles for boosting the performance of photocatalytic hydrogen generation, where they highlighted the importance of donor/acceptor heterostructures in facilitating exciton dissociation.…”