The Intrinsic Role of the Fusion Mode and Electron‐Deficient Core in Fused‐Ring Electron Acceptors for Organic Photovoltaics. (8th June 2022)

• Record Type: Journal Article
• Authors: Guo, Yuan; Han, Guangchao; Yi, Yuanping
• Is Part Of: Angewandte Chemie. Volume 134:Number 30(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-08
• Subjects: Fused-Ring Electron Acceptors -- Fusion Mode -- Small Molecule -- Solar Cells; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202205975
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The A‐DA′D‐A fused‐ring electron acceptors with an angular fusion mode and electron‐deficient core has significantly boosted organic photovoltaic efficiency. Here, the intrinsic role of the peculiar structure is revealed by comparing representative A‐DA′D‐A acceptor Y6 with its A‐D‐A counterparts having different fusion modes. Owing to the more delocalized HOMO and deeper LUMO level, Y6 exhibits stronger and red‐shifted absorption relative to the linear and angular fused A‐D‐A acceptors, respectively. Moreover, the change from linear to angular fusion substantially reduces the electron‐vibration couplings, which is responsible for the faster exciton diffusion, exciton dissociation, and electron transport for Y6 than the linear fused A‐D‐A acceptor. Notably, the electron‐vibration coupling for exciton dissociation is further decreased by introducing the electron‐deficient core, thus contributing to the efficient charge generation under low driving forces in the Y6‐based devices. Abstract : The angular fusion mode and electron‐deficient core have different effects in the A‐DA′D‐A acceptors. The angular fusion is beneficial to enhance light absorption and reduce electron‐vibration couplings to simultaneously accelerate exciton diffusion, exciton dissociation, and electron transport, while introducing the electron‐deficient core will lead to deeper frontier orbitals, bathochromic absorption, and further promote exciton dissociation.