Locally induced Stark shifts of collective excitonic modes in polyradical aggregates

• Amandeep Sagwal,
• Rodrigo Cezar de Campos Ferreira,
• Petr Kahan,
• Maximilian Rödel,
• Jindřich Nejedlý,
• Jiří Doležal and
• Martin Švec

Beilstein J. Nanotechnol. 2026, 17, 1185–1193, doi:10.3762/bjnano.17.81

• aggregates composed of radical chromophores. With the strong optical enhancement provided by tip-enhanced photoluminescence spectroscopy, we observe fingerprints of bright and dark excitonic modes appearing due to interexciton coupling and induced changes in their spectra with the electric field locally

• , nanocavity coupling, and electrostatic charge inhomogeneities in the clusters. This sensitivity to the external parameters demonstrates an effective means of control over radical excitonic aggregates. Keywords: chromophore; dark states; exciton; Stark shift; TEPL; tip-enhanced photoluminescence

• tip-enhanced photoluminescence (TEPL) technique, which allows one to access the excitonic modes without the need for an external bias [35][36][37]. Notably, this approach remains currently underexploited. In this work, we investigate the effect of the electric field on the photon response of

Defects and defect-mediated engineering of two-dimensional materials: challenges and open questions

• Arkady V. Krasheninnikov,
• Matthias Batzill,
• Anouar-Akacha Delenda,
• Marija Drndić,
• Chris Ewels,
• Katharina J. Franke,
• Mahdi Ghorbani-Asl,
• Alexander Holleitner,
• Ado Jorio,
• Ute Kaiser,
• Daria Kieczka,
• Hannu-Pekka Komsa,
• Jani Kotakoski,
• Manuel Längle,
• David Lamprecht,
• Yun Liu,
• Steven G. Louie,
• Janina Maultzsch,
• Thomas Michely,
• Katherine Milton,
• Anna Niggas,
• Hanako Okuno,
• Joshua A. Robinson,
• Marika Schleberger,
• Bruno Schuler,
• Alexander Shluger,
• Kazu Suenaga,
• Kristian S. Thygesen,
• Richard A. Wilhelm,
• E. Harriet Åhlgren and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2026, 17, 454–488, doi:10.3762/bjnano.17.31

• sub-nanometer precision, while also probing vibronic structure and photon statistics in situ. Complementary approaches, such as tip-enhanced photoluminescence, extend this toolbox by enabling nanoscale hyperspectral mapping and photon correlation without charge injection. Together, these techniques