Syntheses and Properties of Random Copolymers Using Thienyl-Thieno-Indole and Bithiophene-Dicarboximide with Different Ratios

• Published in: Macromolecular research Vol. 27; no. 5; pp. 470 - 475
• Main Authors: Kim, Juae, Jeong, Ina, Lee, Jihoon, Park, Sung Heum, Suh, Hongsuk
• Format: Journal Article
• Language: English
• Published: Seoul The Polymer Society of Korea 01.05.2019; Springer Nature B.V; 한국고분자학회
• Subjects: Absorptivity; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Copolymers; Nanochemistry; Nanotechnology; Photons; Photovoltaic cells; Physical Chemistry; Polymer Sciences; Soft and Granular Matter; Solar cells; 고분자공학; photovoltaic cells; indole (TTI); random polymer; 6-(2-thienyl)-4; alkyl-2,2′-bithiophene-3,3′-dicarboximide unit (BTI); thieno[3,2
• ISSN: 1598-5032; 2092-7673
• DOI: 10.1007/s13233-019-7067-7

We synthesized random copolymers using 6-(2-thienyl)-4 H -thieno[3,2- b ]indole (TTI) and N -alkyl-2,2′-bithiophene-3,3′-dicarboximide (BTI) as the electron-rich and deficient units for the polymer solar cells (PSCs). Herein, by using different feed ratios of electron-deficient unit, the push-pull type copolymers were synthesized by Stille polymerization of TTI, BTI and thiophene linkage. Out of the series PBTI3 with 7:3 ratio of TTI and BTI showed the highest molar absorption coefficient and mobility, which is favorable for efficiently harvesting solar photons and higher photo-induced carriers to improve the J SC . Among devices of synthesized copolymers, PBTI3 /PC 71 BM (1:2) (with 3% DIO additive) blend-based PSCs showed the best performance with a J SC of 6.78 mA/cm 2 , a V OC of 0.72 V, a FF of 0.54 and a PCE of 2.64%.