Revealing the Electrophilic‐Attack Doping Mechanism for Efficient and Universal p‐Doping of Organic Semiconductors
Jing Guo, Ying Liu, Pingan Chen, Xinhao Wang, Yanpei Wang, Jing Guo, Xincan Qiu, Zebing Zeng, Lang Jiang, Yuanping Yi, Shun Watanabe, Lei Liao, Yugang Bai, Thuc‐Quyen Nguyen, Yuanyuan Hu
Abstract
Doping is of great importance to tailor the electrical properties of semiconductors. However, the present doping methodologies for organic semiconductors (OSCs) are either inefficient or can only apply to some OSCs conditionally, seriously limiting their general applications. Herein, a novel p-doping mechanism is revealed by investigating the interactions between the dopant trityl tetrakis(pentafluorophenyl) borate (TrTPFB) and poly(3-hexylthiophene) (P3HT). It is found that electrophilic attack of the trityl cations on thiophenes results in the formation of tritylated thiophenium ions, which subsequently induce electron transfer from neighboring P3HT chains to realize p-doping. This unique p-doping mechanism enables TrTPFB to p-dope various OSCs including those with high ionization energy (IE ≈ 5.8 eV). Moreover, this doping mechanism endows TrTPFB with strong doping capability, leading to doping efficiency of over 80% in P3HT. The discovery and elucidation of this novel doping mechanism not only points out that strong electrophiles are a class of efficient p-dopants for OSCs, but also provides new opportunities toward highly efficient doping of various OSCs.