Comprehensive theoretical and experimental study of near infrared absorbing copolymers based on dithienosilole

Abstract

A new conjugated copolymer with alternating dithienosilole and thienoisoindigo units displays improved near-infrared absorption compared to previously reported dithienosilole-based copolymers.

Diketo-Pyrrolo Pyrrole-Based Acceptor-Acceptor Copolymers with Deep HOMO and LUMO Levels Absorbing in the Near Infrared

“…All these spectra allowed the calculation of optical bandgaps of 1.3, 1.2, 1.0, and 0.9 eV for P(DPP-DPPeH), P(DPP-DPPC12), P(DPP-DAP), and P(DPP-BTPBF), respectively. These band gaps are very small and quite similar to that of the corresponding D-A copolymers reported in our previous publication with DTS as donor unit (reported in Table 2 for comparison) [47]. In order to investigate further the effects of alternating two acceptor monomers on the electronic levels, HOMO and LUMO levels were determined by cyclic voltammetry.…”

“…The electronic and optical properties of copolymers were computed by using the oligomer approach [43,[47][48][49][50][51][52]. The molecular structures of finite-size (DA) n oligomers (n = 1-5) were optimized at the density functional theory (DFT) level in the gas phase using the M06-2X exchange-correlation functional [53] (XCF) and the 6-311G(d) basis set (see details in the supporting information).…”

“…Computational chemistry provided a direct insight into the impact of chemical modifications in these structurally similar systems. DFT calculations have been also compared to previously reported theoretical results on D-A' copolymers [47].…”

Molecular level understanding of the chalcogen atom effect on chalcogen-based polymers through electrostatic potential, non-covalent interactions, excited state behaviour, and radial distribution function

“…The interactions between polymer and solvent molecules control the solubility of polymers. 50,51 These interactions also control the film morphology of polymer solar cells. The polymer-solvent interactions are strongly dependent on the materials.…”

Decrease the Bandgap of Conjugated Polymers: What is the Effect of Alternating Two Acceptor Units Instead of Donor and Acceptor on Optoelectronic Properties

“…However, to strongly shift the absorption range toward the infra-red, the strategy of copolymers alternating electron rich (donor) and electron poor (acceptor) comonomers is one of well-known method leading to donor-acceptor copolymers (D-A) called low bandgap polymers [3]. From our experience based on experimental and computational results, we found that in D-A copolymers, the change of comonomer D based on dithiophene bridged by C, N or Si, while keeping A the same, has little effect on the final opto-electronic properties [4]. Indeed, roughly the same transition energies were obtained.…”