title: Toward a rational design of poly(2,7-carbazole) derivatives for solar cells.
abstract: On the basis of theoretical models and calculations, several alternating polymeric structures have been investigated to develop optimized poly(2,7-carbazole) derivatives for solar cell applications. Selected low band gap alternating copolymers have been obtained via a Suzuki coupling reaction. A good correlation between DFT theoretical calculations performed on model compounds and the experimental HOMO, LUMO, and band gap energies of the corresponding polymers has been obtained. This study reveals that the alternating copolymer HOMO energy level is mainly fixed by the carbazole moiety, whereas the LUMO energy level is mainly related to the nature of the electron-withdrawing comonomer. However, solar cell performances are not solely driven by the energy levels of the materials. Clearly, the molecular weight and the overall organization of the polymers are other important key parameters to consider when developing new polymers for solar cells. Preliminary measurements have revealed hole mobilities of about 1 x 10(-3) cm2 x V(-1) x s(-1) and a power conversion efficiency (PCE) up to 3.6%. Further improvements are anticipated through a rational design of new symmetric low band gap poly(2,7-carbazole) derivatives.
authors: Département de Chimie, Université Laval, Quebec City, Quebec, G1K 7P4, Canada.
authors: Nicolas
authors: N
authors: Blouin
authors: Alexandre
authors: A
authors: Michaud
authors: David
authors: D
authors: Gendron
authors: Salem
authors: S
authors: Wakim
authors: Emily
authors: E
authors: Blair
authors: Rodica
authors: R
authors: Neagu-Plesu
authors: Michel
authors: M
authors: Belletête
authors: Gilles
authors: G
authors: Durocher
authors: Ye
authors: Y
authors: Tao
authors: Mario
authors: M
authors: Leclerc