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Adduct-based p-doping of organic semiconductors


Electronic doping of organic semiconductors is essential for their usage in highly efficient optoelectronic devices. Although molecular and metal complex-based dopants have already enabled significant progress of devices based on organic semiconductors, there remains a need for clean, efficient and low-cost dopants if a widespread transition towards larger-area organic electronic devices is to occur. Here we report dimethyl sulfoxide adducts as p-dopants that fulfil these conditions for a range of organic semiconductors. These adduct-based dopants are compatible with both solution and vapour-phase processing. We explore the doping mechanism and use the knowledge we gain to ‘decouple’ the dopants from the choice of counterion. We demonstrate that asymmetric p-doping is possible using solution processing routes, and demonstrate its use in metal halide perovskite solar cells, organic thin-film transistors and organic light-emitting diodes, which showcases the versatility of this doping approach.

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Fig. 1: Doping ability of the DMSO–HBr adduct for various HTMs.
Fig. 2: Mechanism of doping by the DMSO–HBr adduct.
Fig. 3: Thermal stability of the doped MeO-TPD films.
Fig. 4: Asymmetric doping in hole-only devices.
Fig. 5: Usage of adduct-based dopants in optoelectronic devices.

Data availability

The datasets used in this work are available in the Oxford University Research Archive repository48.


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This research has mainly received funding from the European Commission (PERTPV- agreement no. 763977) and EPSRC (EP/M005143/1 and EP/S004947/1). M.R. has received funding from the EC FP 7 MSCA—Career Integration Grant (630864) and M.R. and S.V.K. acknowledge funding from the EPSRC WAFT project (EP/M015173/1). R.W. is supported by EPSRC CDT Plastic Electronics (EP/L016702/1). P.K.N. acknowledges support from the Department of Atomic Energy, Government of India, under Project Identification no. RTI 4007 and SERB India core research grant (CRG/2020/003877). F.Z., X.L. and A.K. acknowledge funding from National Science Foundation under grants DMR-1506097 and DMR-1807797. S.N. acknowledges Marie Skłodowska-Curie Actions individual fellowships (grant agreement no. 659306) and a start-up grant from CSIR-IMMT, India. T.M. and V.G. acknowledge funding from European Regional Development Fund (project no. 01.2.2-LMT-K-718-03-0040) under a grant agreement with the Research Council of Lithuania (LMTLT). T.D.A. and A.B. are grateful to King Abdullah University of Science and Technology (KAUST), KAUST Solar Centre and KAUST Office for Sponsored Research (OSR) for the financial support under award no: OSR-2019-CRG8-4095, no. OSR-2018-CARF/CCF-3079. J.L. and C.G. are grateful for support for the NanoSIMS facility from EPSRC under grant EP/M018237/1. We thank I. McPherson for his help in mass spectrometry measurements and M. Heeney for providing the C16IDT-BT polymer.

Author information




N.S. and P.K.N. conceived and executed the initial proof-of-concept experiments and unravelled the mechanism of doping. P.K.N. proposed the dopant system. H.J.S. proposed the asymmetric doping and N.S. designed and performed the experiments. N.S. and R.W. performed the conductivity measurements. N.S. and R.W. performed the doping stability test under the supervision of M.R. S.V.K. performed the ellipsometry measurements, analyses and simulation under the supervision of M.R. R.W. fabricated the OLEDs under the supervision of M.R. and N.S. fabricated all the other the devices used in this work. S.N. and P.K.N. performed the attenuated total reflection FTIR measurements. F.Z. and X.L. did the UPS, XPS and Kelvin probe measurements under the supervision of A.K. F.Z. did the AFM measurements. J.L. did the nanosecondary ion mass spectrometry measurements with inputs from P.K.N. and N.S. C.G. planned and helped interpret the nanosecondary ion mass spectrometry measurements. N.S. and Y.-H.L. performed the capacitance–voltage measurements. H.S.B. performed the quantum chemical calculations. T.M. conducted the synthesis of the HTM V886 and V.G. supervised the synthesis. A.B. fabricated the OTFTs and performed the electrical characterization under the supervision of T.D.A. T.D.A., Y.-H.L. and A.B. interpreted the results and provided the analysis of the OTFTs. N.S. and P.K.N. wrote the first draft. All the authors contributed to the analysis of the results, discussion of the content and revisions of the manuscript. P.K.N. and H.J.S. supervised the project.

Corresponding authors

Correspondence to Pabitra K. Nayak or Henry J. Snaith.

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Competing interests

A patent based on this work has been filed (international application number PCT/GB2018/053014) by the University of Oxford. H.J.S. is a co-founder of Oxford PV Ltd and Helio Display Materials. The remaining authors declare no competing interests.

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Peer review information Nature Materials thanks Adam Moule and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Information

Characterization, Supplementary Figs. 1–42, Notes 1–9 and Tables 1–6.

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Sakai, N., Warren, R., Zhang, F. et al. Adduct-based p-doping of organic semiconductors. Nat. Mater. (2021).

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