Photoconductive organic-inorganic composite materials and their applications in optoelectronic devices

• Applicant: Professor Dr. Frank Würthner
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation ; Synthesis and Properties of Functional Materials
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 390252575

• Final Report Year: 2022

Final Report Abstract

A new class of perylene bisimide (PBI) dyes bearing two or four hydroxy groups in bay area has been synthesized by a direct manganese dioxide hydroxylation protocol (twofold hydroxylation) and via a CuBrmediated methoxylation of tetrabromo-PBIs and subsequent hydrolysis (tetrafold hydroxylation), respectively. The hydroxy functional groups in the respective PBI bay area(s) could be successfully bridged by boron, carbon and silicon units to afford a new class of highly fluorescent dyes with excellent solubility. Based on titration experiments with base and zinc salts we assume similar bridges to form with zinc ions that constitute the photofunctional components that are formed upon incorporation of these PBI dyes in zinc oxide (ZnO) interlayers. These PBI-doped ZnO cathode interlayers afforded organic solar cells (OSCs) with various bulk heterojunction layers (fullerene and non-fullerene) of improved performance and device stability compared to those based on pristine ZnO cathode interlayers. Inverted OSCs with active layers composed of polymer donors and non-fullerene acceptors afforded power conversion efficiencies (PCEs) of up to 16%. For interlayers based on a new class of 2,6-di-tert-butyl-phenol-functionalized PBIs an even higher PCE of up to 17.2% was reached. Initial studies demonstrated that titanium dioxide nanoparticles can be photosensitized in a similar way by fixation of PBI dyes on the surfaces via carboxylate functional groups, leading to the lightinduced reduction of water into hydrogen via PBI radical anion and dianion species in the presence of triethanolamine as sacrificial reagent.

Publications

• Enhanced Electron Transportation by Dye Doping in Very Low-Temperature (<130 °C)-Processed Sol–Gel ZnO toward Flexible Organic Solar Cells. ACS Applied Materials & Interfaces, 11(37), 34151-34157.
  Wen, Xinbo; Fang, Shaomao; Xu, Yucheng; Zheng, Nan; Liu, Linlin; Xie, Zengqi & Würthner, Frank
  
• Tetrahydroxy‐Perylene Bisimide Embedded in a Zinc Oxide Thin Film as an Electron‐Transporting Layer for High‐Performance Non‐Fullerene Organic Solar Cells. Angewandte Chemie, 131(37), 13185-13189.
  Wen, Xinbo; Nowak‐Król, Agnieszka; Nagler, Oliver; Kraus, Felix; Zhu, Na; Zheng, Nan; Müller, Matthias; Schmidt, David; Xie, Zengqi & Würthner, Frank
  
• Consecutive Charging of a Perylene Bisimide Dye by Multistep Low‐Energy Solar‐Light‐Induced Electron Transfer Towards H2 Evolution. Angewandte Chemie, 132(26), 10449-10453.
  Xu, Yucheng; Zheng, Jiaxin; Lindner, Joachim O.; Wen, Xinbo; Jiang, Nianqiang; Hu, Zhicheng; Liu, Linlin; Huang, Fei; Würthner, Frank & Xie, Zengqi
  
• Increased Electron Transport and Hole Blocking in an Aqueous Solution Processed Dye-Doped ZnO Cathode Interlayer for High Performance Organic Solar Cells. ACS Applied Energy Materials, 3(2), 1694-1701.
  Luo, Yinqi; Fang, Shaomao; Zheng, Nan; Liu, Linlin; Würthner, Frank & Xie, Zengqi
  
• Phenol‐Functionalized Perylene Bisimides as Amine‐Free Electron Transporting Interlayers for Stable Nonfullerene Organic Solar Cells. Advanced Functional Materials, 32(17).
  Wen, Xinbo; Zhang, Yu; Xie, Guojing; Rausch, Rodger; Tang, Ningning; Zheng, Nan; Liu, Linlin; Würthner, Frank & Xie, Zengqi
  
• Yellow Light-Emitting Highly Soluble Perylene Bisimide Dyes by Acetalization of Bay-Hydroxy Groups. Organic Letters, 24(37), 6839-6844.
  Nagler, Oliver; Krause, Ana-Maria; Shoyama, Kazutaka; Stolte, Matthias; Dubey, Rajeev K.; Liu, Linlin; Xie, Zengqi & Würthner, Frank