Difluorobenzothiadiazole based two-dimensional conjugated polymers with triphenylamine substituted moieties as pendants for bulk heterojunction solar cells

Abstract

Abstract. Three donor/acceptor (D/A)-type two-dimensional polythiophenes (PTs; PBTFA13, PBTFA12, PBTFA11) featuring difluorobenzothiadiazole (DFBT) derivatives as the conjugated (acceptor) units in the polymer backbone and tertbutyl-substituted triphenylamine (tTPA)-containing moieties as (donor) pendants have been synthesized and characterized. These PTs exhibited good thermal stabilities, broad absorption spectra, and narrow optical band gaps. The cutoff wavelength of the UV-Vis absorption band was red-shifted upon increasing the content of the DFBT units in the PTs. Bulk heterojunction solar cells having an active layer comprising blends of the PTs and fullerene derivatives [6,6] phenyl-C 61/71 -butyric acid methyl ester (PC 61 BM/PC 71 BM) were fabricated; their photovoltaic performance was strongly dependent on the content of the DFBT derivative in the PT. Incorporating a suitable content of the DFBT derivative in the polymer backbone enhanced the solar absorption ability and conjugation length of the PTs. The photovoltaic properties of the PBTFA13-based solar cells were superior to those of the PBTFA11-and PBTFA12-based solar cells.

Thermo-Optical and Structural Studies of Iodine-Doped Polymer: Fullerene Blend Films, Used in Photovoltaic Structures

“…For many years, this type of polymer:fullerene structure has been recognized as a model system for the organic photovoltaic application, despite its rather low performance as an active layer [ 6 ]. In addition, other conjugated polymers based on polythiophenes (PTs) have been investigated in BHJ photovoltaic structures [ 7 , 8 ].…”

Synthesis of the diketopyrrolopyrrole/terpyridine substituted carbazole derivative based polythiophenes for photovoltaic cells

“…According to procedures reported in the literature, 4 0 -(4-bromophenyl)-2-2 0 :6 0 ,2 00 -terpyridine (1), 3,6-di(2-bromothien-5-yl)-2,5-di(2-ethylhexyl)pyrrolo [3,4-c]pyrrole-1,4-dione (3), and 2,5-bis(trimethylstannyl)thiophene (4) were synthesized. 18,28,51 The syntheses of 3,6-dibromo-9-(4-[2,6-di(pyrid-2-yl) pyrid-4-yl]phenyl)-9H-carbazole (2) and the PTs PDPP, PDPCz21, and PDPCz11 are presented in Scheme 1.…”

“…25 Many PVCs displaying good PV performance have featured PTs containing electron-donor and -acceptor (D-A)-type structures. [26][27][28] Such electron-and hole-transporting segments are responsible for a broader range of light absorption and the higher electron and hole mobilities of the resulting photoenergy conversion layers and, therefore, the enhanced PV performance of the PVCs. [29][30][31] Triphenylamine (TPA) and carbazole derivatives are among the most popular electron donor groups because of their good electron-donating and holetransporting performance and their good solubility in the organic solvents.…”