Low‐Volatility Fused‐Ring Solid Additive Engineering for Synergistically Elongating Exciton Lifetime and Mitigating Trap Density Toward Organic Solar Cells of 20.5% Efficiency

Volatile solid additives (VSAs) with single or fused-ring structures have attracted much attention for enhancing power conversion efficiencies (PCEs) of organic solar cells (OSCs). While the working mechanisms of high-volatility single-ring additives have been well studied, the influence of low-volatility fused-ring VSAs on molecular aggregations and exciton/carrier dynamics remains still unclear. Herein, 3,6-dibromothieno[3,2-b]thiophene (3,6TTBr) is selected as a representative low-volatility fused-ring VSA to elucidate its working mechanism. Via the theoretical and experimental joint investigation, it is found that rigid and planar 3,6TTBr molecules adsorb onto the terminal units of L8-BO (acceptor),…

• SS
  Salt Science Research Foundation

  Award: BL16B1
• NN
  National Natural Science Foundation of China

  Awards: 62105129, BL16B1, 22275024
• GO
  Government of Jiangsu Province

  Award: KYCX22_3032
• NS
  Natural Science Foundation of Jiangsu Province

  Award: BK20240042
• SC
  South China University of Technology

  Award: 2024‐skllmd‐26
• SK
  State Key Laboratory of Luminescent Materials and Devices
• HE
  Higher Education Discipline Innovation Project
• SP
  Sichuan Province Science and Technology Support Program

  Award: 2023NSFSC0990