Facile strategy for third component optimization in wide-band-gap π-conjugated polymer donor-based efficient ternary all-polymer solar cells

Thavamani Gokulnath, Kui Feng, Ho Yeol Park, Yeongju Do, Hyungjin Park, Rajalapati Durga Gayathri, Saripally Sudhaker Reddy, Jehan Kim, Xugang Guo, Jinhwan Yoon, Sung Ho Jin

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7 Citations (Scopus)

Abstract

Emerging organic solar cells based on a ternary strategy is one of the most effective methods for improving the blend film morphology, absorption ability, and device performances. On the other hand, this strategy has had very limited success in all-polymer solar cells (all-PSCs) because of the scarcity of new polymers and the challenges faced during third component optimization. Herein, highly efficient ternary all-PSCs were developed from siloxane-functionalized side chains with a wide-band-gap (Eg) polymer, Si-BDT, which is blended with a medium and ultra-narrow Eg polymer donor and acceptor, PTB7-Th, and DCNBT-TPIC. An impressive power conversion efficiency (PCE) of 13.45% was achieved in the ternary all-PSCs [PTB7-Th(0.6):Si-BDT(0.4):DCNBT-TPIC(0.6)] with the addition of 0.4 wt equivalent Si-BDT into binary all-PSCs [PTB7-Th(1):DCNBT-TPIC(0.6) PCE of 10.11%]. In contrast, the binary all-PSCs with a Si-BDT(1):DCNBT-TPIC(0.6) active layer only exhibited a good PCE of 9.92%. More importantly, the siloxane-functionalized side chains increase the light-absorption ability, carrier mobility, blend miscibility, and film morphology in ternary devices compared to those of the binary devices. Hence, exciton dissociation, charge carrier transport, and suppressed recombination properties were facilitated. In the presence of Si-BDT, both binary and ternary all-PSCs PCEs are significantly improved. Indeed, 13.45% PCE is one of the best values reported for all-PSCs except for those based on polymerized small molecule acceptors. In addition, the ternary all-PSCs showed excellent environmental and thermal stabilities with 95 and 84% of the initial PCE retained after 900 and 500 h, respectively. These results offer effective device engineering, providing a new avenue for improving the device performance in ternary all-PSCs.

Original languageEnglish
Pages (from-to)11211-11221
Number of pages11
JournalACS Applied Materials and Interfaces
Volume14
Issue number9
DOIs
Publication statusPublished - 9 Mar 2022

Keywords

  • complementary absorption
  • device performance
  • morphology control
  • polymer donor
  • ternary all-polymer solar cells
  • organic photovoltaics

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