title: Molecular-sized fluorescent nanodiamonds.
abstract: Doping of carbon nanoparticles with impurity atoms is central to their application. However, doping has proven elusive for very small carbon nanoparticles because of their limited availability and a lack of fundamental understanding of impurity stability in such nanostructures. Here, we show that isolated diamond nanoparticles as small as 1.6 nm, comprising only ∼400 carbon atoms, are capable of housing stable photoluminescent colour centres, namely the silicon vacancy (SiV). Surprisingly, fluorescence from SiVs is stable over time, and few or only single colour centres are found per nanocrystal. We also observe size-dependent SiV emission supported by quantum-chemical simulation of SiV energy levels in small nanodiamonds. Our work opens the way to investigating the physics and chemistry of molecular-sized cubic carbon clusters and promises the application of ultrasmall non-perturbative fluorescent nanoparticles as markers in microscopy and sensing.
authors: General Physics Institute RAS, Vavilov Street 38, 119991 Moscow, Russia.
authors: Igor I
authors: II
authors: Vlasov
authors: Institute of Physical Chemistry and Electrochemistry RAS, Leninsky pr. 31, 119071, Moscow, Russia.
authors: Andrey A
authors: AA
authors: Shiryaev
authors: 3rd Physical Institute and Research Center SCOPE, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
authors: Torsten
authors: T
authors: Rendler
authors: 3rd Physical Institute and Research Center SCOPE, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
authors: Steffen
authors: S
authors: Steinert
authors: 3rd Physical Institute and Research Center SCOPE, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
authors: Sang-Yun
authors: SY
authors: Lee
authors: 3rd Physical Institute and Research Center SCOPE, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
authors: Denis
authors: D
authors: Antonov
authors: Department of Atomic Physics, Budapest University of Technology and Economics, Budapest, Budafoki út 8, H-1111, Hungary.
authors: Márton
authors: M
authors: Vörös
authors: Institute for Quantum Optics, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
authors: Fedor
authors: F
authors: Jelezko
authors: Vernadsky Institute of Geochemistry and Analytical Chemistry RAS, Kosygin Street 19, Moscow, Russia.
authors: Anatolii V
authors: AV
authors: Fisenko
authors: Vernadsky Institute of Geochemistry and Analytical Chemistry RAS, Kosygin Street 19, Moscow, Russia.
authors: Lubov F
authors: LF
authors: Semjonova
authors: Central Facility of Electron Microscopy, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
authors: Johannes
authors: J
authors: Biskupek
authors: Central Facility of Electron Microscopy, University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
authors: Ute
authors: U
authors: Kaiser
authors: Laboratoire CRISMAT, UMR 6508 CNRS ENSICAEN, 6 boulevard Marechal Juin, 14050 Caen, France.
authors: Oleg I
authors: OI
authors: Lebedev
authors: Institute of Physics, University of Tartu, Riia Street 142, 51014 Tartu, Estonia.
authors: Ilmo
authors: I
authors: Sildos
authors: Department of Electrical and Computer Engineering, 3128 Texas A&M University, College Station, Texas 77843-3128, USA.
authors: Philip R
authors: PR
authors: Hemmer
authors: General Physics Institute RAS, Vavilov Street 38, 119991 Moscow, Russia.
authors: Vitaly I
authors: VI
authors: Konov
authors: 1] Department of Atomic Physics, Budapest University of Technology and Economics, Budapest, Budafoki út 8, H-1111, Hungary [2] Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, 1525 Budapest, Hungary.
authors: Adam
authors: A
authors: Gali
authors: 3rd Physical Institute and Research Center SCOPE, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
authors: Jörg
authors: J
authors: Wrachtrup