Transition metal-catalysed molecular n-doping of organic semiconductors

• Published in: Nature (London) 2021-11, Vol.599 (7883), p.67-73
• Main Authors: Guo, Han, Yang, Chi-Yuan, Zhang, Xianhe, Motta, Alessandro, Feng, Kui, Xia, Yu, Shi, Yongqiang, Wu, Ziang, Yang, Kun, Chen, Jianhua, Liao, Qiaogan, Tang, Yumin, Sun, Huiliang, Woo, Han Young, Fabiano, Simone, Facchetti, Antonio, Guo, Xugang
• Format: Article
• Language: English
• Subjects: 639/166/987; 639/301/1005; 639/301/299; Annealing; Catalysis; Catalysts; Charge transport; Conductivity; Dopants; Doping; Efficiency; Electrodes; Gold; Humanities and Social Sciences; multidisciplinary; N-type semiconductors; Nanoparticles; Organic semiconductors; Organometallic complexes; Palladium; Science; Science (multidisciplinary); Semiconductor devices; Semiconductors; Ternary systems; Transition metals; Vapor deposition
• ISSN: 0028-0836; 1476-4687; 1476-4687
• DOI: 10.1038/s41586-021-03942-0

Chemical doping is a key process for investigating charge transport in organic semiconductors and improving certain (opto)electronic devices 1 – 9 . N(electron)-doping is fundamentally more challenging than p(hole)-doping and typically achieves a very low doping efficiency ( η ) of less than 10% 1 , 10 . An efficient molecular n-dopant should simultaneously exhibit a high reducing power and air stability for broad applicability 1 , 5 , 6 , 9 , 11 , which is very challenging. Here we show a general concept of catalysed n-doping of organic semiconductors using air-stable precursor-type molecular dopants. Incorporation of a transition metal (for example, Pt, Au, Pd) as vapour-deposited nanoparticles or solution-processable organometallic complexes (for example, Pd 2 (dba) 3 ) catalyses the reaction, as assessed by experimental and theoretical evidence, enabling greatly increased η in a much shorter doping time and high electrical conductivities (above 100 S cm −1 ; ref. 12 ). This methodology has technological implications for realizing improved semiconductor devices and offers a broad exploration space of ternary systems comprising catalysts, molecular dopants and semiconductors, thus opening new opportunities in n-doping research and applications 12 , 13 . Electron doping of organic semiconductors is typically inefficient, but here a precursor molecular dopant is used to deliver higher n-doping efficiency in a much shorter doping time.