Revealing the Electrophilic-Attack Doping Mechanism for Efficient and Universal p-Doping of Organic Semiconductors

Jing Guo; Ying Liu; Ping-An 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

doi:10.1002/advs.202203111

Revealing the Electrophilic-Attack Doping Mechanism for Efficient and Universal p-Doping of Organic Semiconductors

Adv Sci (Weinh). 2022 Nov;9(32):e2203111. doi: 10.1002/advs.202203111. Epub 2022 Sep 11.

Authors

Jing Guo¹, Ying Liu², Ping-An Chen¹, Xinhao Wang², Yanpei Wang², Jing Guo², Xincan Qiu¹, Zebing Zeng², Lang Jiang³, Yuanping Yi³, Shun Watanabe⁴, Lei Liao¹, Yugang Bai², Thuc-Quyen Nguyen⁵, Yuanyuan Hu^{1

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Affiliations

¹ International Science and Technology Innovation Cooperation Base for Advanced Display Technologies of Hunan Province, College of Semiconductors (College of Integrated Circuits), Hunan University, Changsha, 410082, P. R. China.
² State Key Laboratory of Chem-/Bio-Sensing and Chemometrics, School of Chemistry and Chemical Engineering, Hunan University, Changsha, Hunan, 410082, P. R. China.
³ Beijing National Laboratory for Molecular Sciences, Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China.
⁴ Material Innovation Research Center (MIRC) and Department of Advanced Material Science, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 77-8561, Japan.
⁵ Center for Polymers and Organic Solids, Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, CA, 93106, USA.
⁶ Shenzhen Research Institute of Hunan University, Shenzhen, 518063, P. R. China.

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.

Keywords: cation; doping efficiency; doping mechanism; electrophilic attack; organic semiconductors.

Abstract

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