Highly Secure Plasmonic Encryption Keys Combined with Upconversion Luminescence Nanocrystals

Kisun Park, Minji Park, Ho Seong Jang, Ji Hun Park, Jaekyun Kim, Younghak Cho, Il Ki Han, Dongjin Byun, Hyungduk Ko

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


This study proposes a novel and highly secure encryption technology based on plasmonic-enhanced upconversion luminescence (UCL). The technology can be realized by a disordered plasmonic nanostructure composed of a transferred metal nanoparticle–UC nanocrystals (UCNC)–metal (tMUM) film using the graphene transfer process, in which the metal nanoparticles that formed on the graphene layer are transferred using Scotch tape. The plasmonic tMUM film strongly enhances the UCL by a factor of 200 mainly because of the excitation of the gap plasmon polaritons. Meanwhile, the UCNCs in direct contact with the metal film result in luminescence quenching caused by a nonradiative process. Herein, a highly secure anti-counterfeit film is developed, which is very hard to duplicate and cannot be reused, using two conflicting features (i.e., emission enhancement and quenching phenomena). The UCL is strongly amplified only when the first (i.e., a random metal nanoparticle array) and second (i.e., UCNCs on a Ag film) codes are very precisely overlapped as designed, thereby generating the originally designed final code. Therefore, our novel high-level security device is expected to be easily applied to protect and identify genuine products.

Original languageEnglish
Article number1800369
JournalAdvanced Functional Materials
Issue number21
Publication statusPublished - 2018 May 24

Bibliographical note

Funding Information:
This research was financially supported by the National Research Foundation of Korea (Grant Nos. NRF-2013M3C1A3065040 and

Funding Information:
NRF-2017M1A2A2048904), the Energy Technology Development Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP grant; Grant No. 20153030012870), and the KIST Institutional Research Program (Grant No. 2E26970).

Publisher Copyright:
© 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim


  • encryption
  • graphene transfer
  • plasmonic enhancement
  • upconversion

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • General Chemistry
  • General Materials Science
  • Electrochemistry
  • Biomaterials


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