Regio-regular alternating diketopyrrolopyrrole-based D1-A-D2-A terpolymers for the enhanced performance of polymer solar cells

Myeongjae Lee, Taehyo Kim, Hoai Van T. Nguyen, Hye Won Cho, Kyung Koo Lee, Jong Ho Choi, Bongsoo Kim, Jin Young Kim

Research output: Contribution to journalArticle

Abstract

We designed and synthesized regio-regular alternating diketopyrrolopyrrole (DPP)-based D1-A-D2-A terpolymers (PDPPF2T2DPP-T2, PDPPF2T2DPP-TVT, and PDPPF2T2DPP-DTT) using a primary donor (D1) [3,3′-difluoro-2,2′-bithiophene (F2T2)] and a secondary donor (D2) [2,2′-bithiophene (T2), (E)-1,2-di(thiophen-2-yl)ethene (TVT), or dithieno[3,2-b:2′,3′-d]thiophene (DTT)]. A PDPP2DT-F2T2 D-A polymer was synthesized as well to compare optical, electronic, and photovoltaic properties. The absorption peaks of the terpolymers (PDPPF2T2DPP-T2, PDPPF2T2DPP-TVT, and PDPPF2T2DPP-DTT) were longer (λmax = 801-810 nm) than the peak of the PDPP2DT-F2T2 polymer (λmax = 799 nm), which is associated with the high-lying HOMO levels of the terpolymers (-5.08 to -5.13 eV) compared with the level of the PDPP2DT-F2T2 polymer (-5.38 eV). The photovoltaic properties of these DPP-based polymers were investigated under simulated AM 1.5G sunlight (100 mW cm-2) with a conventional structure (ITO/PEDOT:PSS/polymer:PC71BM/Al). The open-circuit voltages (Voc) of photovoltaic devices containing the terpolymers were slightly lower (0.68-0.70 V) than the Voc of the device containing the PDPP2DT-F2T2 polymer (0.79 V). The short-circuit current (Jsc) of the PDPPF2T2DPP-DTT device was significantly improved (14.14 mA cm-2) compared with that of the PDPP2DT-F2T2 device (8.29 mA cm-2). As a result, the power conversion efficiency (PCE) of the PDPPF2T2DPP-DTT device (6.35%) was increased by 33% compared with that of the simple D-A-type PDPP2DT-F2T2 device (4.78%). The highest Jsc and PCE values (the PDPPF2T2DPP-DTT device) were attributed to an optimal nanoscopically mixed morphology and strong interchain packing with a high face-on orientation in the blend film state. The study demonstrated that our strategy of using multiple donors in a regio-regular alternating fashion could fine-tune the optical, electronic, and morphological properties of D-A-type polymers, enhancing the performance of polymer solar cells.

Original languageEnglish
Pages (from-to)42096-42109
Number of pages14
JournalRSC Advances
Volume9
Issue number72
DOIs
Publication statusPublished - 2019 Jan 1

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

Fingerprint Dive into the research topics of 'Regio-regular alternating diketopyrrolopyrrole-based D<sub>1</sub>-A-D<sub>2</sub>-A terpolymers for the enhanced performance of polymer solar cells'. Together they form a unique fingerprint.

  • Cite this

    Lee, M., Kim, T., Nguyen, H. V. T., Cho, H. W., Lee, K. K., Choi, J. H., Kim, B., & Kim, J. Y. (2019). Regio-regular alternating diketopyrrolopyrrole-based D1-A-D2-A terpolymers for the enhanced performance of polymer solar cells. RSC Advances, 9(72), 42096-42109. https://doi.org/10.1039/c9ra08858j