Sub-4 nm mapping of donor-acceptor organic semiconductor nanoparticle composition

Ingemar Persson; Hugo Laval; Sylvain Chambon; Gwenael Bonfante; Kazuhiko Hirakawa; Guillaume Wantz; Benjamin Watts; Matthew A Marcus; Xiaoxue Xu; Lei Ying; Girish Lakhwani; Mats R Andersson; Julie M Cairney; Natalie P Holmes

doi:10.1039/d3nr00839h

Sub-4 nm mapping of donor-acceptor organic semiconductor nanoparticle composition

Nanoscale. 2023 Mar 30;15(13):6126-6142. doi: 10.1039/d3nr00839h.

Authors

Ingemar Persson^{1

2}, Hugo Laval³, Sylvain Chambon⁴, Gwenael Bonfante⁴, Kazuhiko Hirakawa⁴, Guillaume Wantz³, Benjamin Watts⁵, Matthew A Marcus⁶, Xiaoxue Xu⁷, Lei Ying⁸, Girish Lakhwani^{9

10}, Mats R Andersson¹¹, Julie M Cairney^{1

12}, Natalie P Holmes^{1

10

12}

Affiliations

¹ Australian Centre for Microscopy and Microanalysis, University of Sydney, Sydney, NSW 2006, Australia. natalie.holmes@sydney.edu.au.
² Thin Film Physics, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-58183 Linköping, Sweden.
³ University of Bordeaux, IMS, CNRS, UMR 5218, Bordeaux INP, ENSCBP, F-33405 Talence, France.
⁴ LIMMS/CNRS-IIS (IRL2820), Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo, 153-8505, Japan.
⁵ Paul Scherrer Institute, 5232 Villigen-PSI, Switzerland.
⁶ Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
⁷ School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, NSW 2007, Australia.
⁸ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China.
⁹ ARC Centre of Excellence in Exciton Science, School of Chemistry, University of Sydney, Sydney, NSW 2006, Australia.
¹⁰ The University of Sydney Nano Institute, Faculty of Science, University of Sydney, Sydney, NSW 2006, Australia.
¹¹ Flinders Institute for Nanoscale Science and Technology, Flinders University, Adelaide, South Australia 5042, Australia.
¹² School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney, NSW 2006, Australia.

PMID: 36939532
DOI: 10.1039/d3nr00839h

Abstract

We report, for the first time, sub-4 nm mapping of donor : acceptor nanoparticle composition in eco-friendly colloidal dispersions for organic electronics. Low energy scanning transmission electron microscopy (STEM) energy dispersive X-ray spectroscopy (EDX) mapping has revealed the internal morphology of organic semiconductor donor : acceptor blend nanoparticles at the sub-4 nm level. A unique element was available for utilisation as a fingerprint element to differentiate donor from acceptor material in each blend system. Si was used to map the location of donor polymer PTzBI-Si in PTzBI-Si:N2200 nanoparticles, and S (in addition to N) was used to map donor polymer TQ1 in TQ1:PC₇₁BM nanoparticles. For select material blends, synchrotron-based scanning transmission X-ray microscopy (STXM), was demonstrated to remain as the superior chemical contrast technique for mapping organic donor : acceptor morphology, including for material combinations lacking a unique fingerprint element (e.g. PTQ10:Y6), or systems where the unique element is in a terminal functional group (unsaturated, dangling bonds) and can hence be easily damaged under the electron beam, e.g. F on PTQ10 donor polymer in the PTQ10:IDIC donor : acceptor blend. We provide both qualitative and quantitative compositional mapping of organic semiconductor nanoparticles with STEM EDX, with sub-domains resolved in nanoparticles as small as 30 nm in diameter. The sub-4 nm mapping technology reported here shows great promise for the optimisation of organic semiconductor blends for applications in organic electronics (solar cells and bioelectronics) and photocatalysis, and has further applications in organic core-shell nanomedicines.