Lewis‐Pairing‐Induced Electrochemiluminescence Enhancement from Electron Donor‐Acceptor Diads Decorated with Tris(pentafluorophenyl)borane as an Electrochemical Protector

Abstract

AbstractThis study reports an effective peripheral decoration of organic donor‐acceptor diads with B(C6F5)3 for stabilizing electrogenerated radical ions. By employing a common p‐type organic semiconductor benzothienobenzothiophene (BTBT) as the donor, tetracoordinate boron complexes showed improved solution electrochemiluminescence (ECL) intensity, reaching a 156‐fold increase compared to that of the parent diad. The unprecedented Lewis‐pairing‐induced ECL enhancement is attributed to the multiple roles of B(C6F5)3: 1) redistributing frontier orbitals, 2) facilitating electrochemical excitation, and 3) restricting molecular motions. Furthermore, B(C6F5)3 converted the molecular arrangement of BTBT from conventional 2D herringbones into 1D π‐stacks. This robust, highly ordered columnar nanostructure allowed red‐shifting of the crystalline film ECL with electrochemical doping through the electronic coupling pathways of BTBT. Our approach will facilitate the development of elaborate metal‐free ECL systems.