Solubilizing Side Chain Engineering: Efficient Strategy to Improve the Photovoltaic Performance of Novel Benzodithiophene‐Based (X‐DADAD)_n Conjugated Polymers

Abstract

Conjugated polymers represent a promising family of semiconductor materials for thin‐film organic solar cells (OSCs). An efficient approach to improve the photovoltaic performance of conjugated polymers is engineering the side chains attached to the polymer backbone. This work reports the impact of different alkyl substituents on the optoelectronic properties, charge carrier mobilities, thin film morphology, and photovoltaic performance of novel (X‐DADAD)n conjugated polymers incorporating benzo[1,2‐b:4,5‐b′]dithiophene moieties. It has been shown that loading conjugated polymers with appropriate alkyl side chains results in a spectacular performance improvement from 6.8% to 9% in OCSs using a model fullerene acceptor [6,6]‐phenyl‐C71‐butyric acid methyl ester. The obtained results feature side‐chain engineering as a facile and efficient strategy for designing high‐performance conjugated polymers for organic photovoltaics.

Modulation of Dielectric Constant and Photovoltaic Properties of 2,1,3‐benzothiadiazole‐based Alternating Copolymers by Adding Fluorine Atoms to the Backbone of Polymers

“…Scheme 1 shows the synthesis routes for the polymers, The synthesis and characterization of BDT‐Sn were summarized in Supporting Information (Scheme S1, Figure S1). the monomers a and c were prepared following the procedure reported in the references, and the synthesis process of monomer b as described in Supporting Information, and characterized by 1 H NMR spectra before use (Scheme S2, Figures S2–S4) [8e,11] . The polymers named PBDT‐4F‐BTs, PBDT‐8F‐FBTs and PBDT‐10F‐FBTs, were synthesized by Palladium‐catalyzed Stille coupling reaction with BDT‐BFSn and the monomers a , b and c , respectively, and the yields of 84 %, 82 %, and 78 % (Table 1).…”

Remarkable Enhancement of Hole Mobility of Novel DA‐D’‐AD Small Molecules by Thermal Annealing: Effect of the D’‐Bridge Block.

“…Compound 11 was synthesized according to previously reported method [32] using (triisopropyl(thiophen‐2‐yl)silane) (3.3 g, 13.7 mmol), n‐BuLi 2.5 M in hexane (5.48 mL, 13.7 mmol), and benzo[1,2‐ b :4,5‐ b ]dithiophene‐4,8‐dione (1.58 g, 7.1 mmol). Yield was of 31 %.…”

Novel Push-Pull Benzodithiophene-Containing Polymers as Hole-Transport Materials for Efficient Perovskite Solar Cells

“…Compound D1 was prepared using compound 2 (2.7 g, 3.1 mmol), 2.5 M n-BuLi (3.1 mL, 7.8 mmol), TMEDA (1.86 mL, 12.4 mmol), and trimethyltin chloride (1.55 g, 7.8 mmol) according to previously reported methods [ 33 ]. Yield: 90% 1 H NMR (500 MHz, CDCl 3 , δ): 7.72 (s, 2H), 7.23 (s, 2H), 2.83 (t, 4H), 2.61 (t, 4H), 1.65–1.75 (m, 8H), 1.25–1.23 (m, 56H), 0.9–0.8 (m, 12H), 0.45–0.35 (m, 18H) ppm.…”

“…Compound M1 was prepared using 6 (1.0 g, 1.82 mmol), 2,5-bis(trimethylstannyl)thiophene (0.15 g, 0.36 mmol), toluene (50 mL) and tetrakis(triphenylphosphine)palladium(0) (10 mg, 0.47%mol) according to previously reported methods [ 33 ]. Yield: 24% 1 H NMR (CDCl 3 , 500 MHz, δ): 8.51 (s, 2H), 4.20 (t, 4H), 4.12 (t, 4H), 1.92 (m, 4H), 1.55 (m, 4H), 1.43–1.21 (m, 40H), 0.88 (t, 6H), 0.81 (t, 6H) ppm.…”