Possible evidence for quantum-size effects in self-assembled ultrathin films containing conjugated copolymers

H. Hong, M. Tarabia, H. Chayet, D. Davidov, E. Z. Faraggi, Y. Avny, Ronny Neumann, S. Kirstein

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Abstract

We present photoluminescence (PL), UV absorption, electroluminescence and x-ray reflectivity studies of self-assembled multilayer films containing alternate layers of conjugated copolymers, and nonconjugated insulating polymers. We show that the PL emission properties of these organic quantum wells can be "tuned" by a proper choice of the conjugated copolymer and the thickness of the insulating layers. Particularly, some of the self-assembled ultrathin films containing thin (∼7 Å) insulating polymeric layers exhibit a blue shift upon decreasing the thickness of the assembly. The PL shift is roughly proportional to 1ld where d is the thickness of the assembly, as expected for confined photogenerated electron-hole pair in an infinite square potential well. In contrast, the PL emission of similar assemblies but containing thick (∼40 Å) insulating layers is independent of the assembly thickness and exhibit emission in the blue. This may suggest a strong spatial confinement. Light emitting diodes based on self-assembled multilayer films with improved efficiency and stability and with threshold voltage as low as 2.6 V could be fabricated.

Original languageEnglish
Pages (from-to)3082-3088
Number of pages7
JournalJournal of Applied Physics
Volume79
Issue number6
Publication statusPublished - Mar 15 1996

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ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physics and Astronomy (miscellaneous)

Cite this

Hong, H., Tarabia, M., Chayet, H., Davidov, D., Faraggi, E. Z., Avny, Y., Neumann, R., & Kirstein, S. (1996). Possible evidence for quantum-size effects in self-assembled ultrathin films containing conjugated copolymers. Journal of Applied Physics, 79(6), 3082-3088.