Design and synthesis of N-substituted perylene diimide based low band gap polymers for organic solar cell applications

Abstract

Newly designed N-substituted perylene diimide based acceptor copolymers have been characterized and tested for organic solar cells with P3HT in different weight ratios.

Ternary Memory Devices Based on Bipolar Copolymers with Naphthalene Benzimidazole Acceptors and Fluorene/Carbazole Donors

“…The FT-IR spectra of these three polymers were almost identical, clearly indicating the characteristic aromatic C–H stretching at 2922 cm –1 , with aliphatic C–H stretching at 2850 cm –1 , CO stretching at 1717 cm –1 , CC and CN stretching at 1616–1483 cm –1 , and C–N stretching at 1238 cm –1 …”

“…Donor–acceptor (D–A)-type polymers are ideal materials for developing new types of organic memory devices because of their adjustable structure, unique optoelectronic properties, and the possibility of gradually inducing multilevel memory behavior through charge transfer (CT) processes. Appropriate donor and acceptor species are critical in these polymers. − Common electron donors include fluorene, carbazole, benzodithiophene, triphenylamine, and so forth, while typical electron acceptor groups are cyano, oxadiazole, quinoline, pyrimidine, and so forth. Note that the electron-deficient ability of acceptors and electron-donating capability of donors play important roles on the electronic properties of molecules.…”

“…Appropriate donor and acceptor species are critical in these polymers. 31−33 Common electron donors include fluorene, 34 carbazole, 35 benzodithiophene, 36 triphenylamine, 37 and so forth, while typical electron acceptor groups are cyano, 38 oxadiazole, 39 quinoline, 40 pyrimidine, 41 and so forth. Note that the electrondeficient ability of acceptors and electron-donating capability of donors play important roles on the electronic properties of molecules.…”

“…The FT-IR spectra of these three polymers were almost identical, clearly indicating the characteristic aromatic C−H stretching at 2922 cm −1 , with aliphatic C−H stretching at 2850 cm −1 , CO stretching at 1717 cm −1 , CC and CN stretching at 1616−1483 cm −1 , and C−N stretching at 1238 cm −1 . 35 The molecular weight and dispersion of these three polymers were determined by gel permeation chromatograph. As is summarized in Table 1, these three polymers (P1, P2, P3) have high molecular weights and broad polydispersity index (PDI) of 1.93, 1.92, and 1.86, respectively.…”

“…All of these three polymers exhibit two broad absorption bands in the range of 260−300 and 350−400 nm in both NMP solution and film conditions, consistent with previous work. 34,35 The high wavelength absorption band should be attributed to the inherent intramolecular CT transition of the D−A system, while these absorption bands at low wavelength are due to the π−π* transition of the conjugated backbone of the donor or acceptor. 52 Compared with the solution, the absorption maximum of film red shifts with the increased area in virtue of the strong interchain interaction between the polymer backbone and the intermolecular π-stacking, which is favorable for rapid charge transport.…”