DOI QR코드

DOI QR Code

Improvement of Hybrid EL Efficiency in Nanoparticle EL Devices by Insertion of the Layers of PVK and BaF2

  • Lee, Jun-Woo (Department of Electrical Engineering and Institute for Nano Science, Korea University) ;
  • Cho, Kyoung-Ah (Department of Electrical Engineering and Institute for Nano Science, Korea University) ;
  • Kim, Hyun-Suk (Department of Electrical Engineering and Institute for Nano Science, Korea University) ;
  • Park, Byoung-Jun (Department of Electrical Engineering and Institute for Nano Science, Korea University) ;
  • Kim, Sang-Sig (Department of Electrical Engineering and Institute for Nano Science, Korea University) ;
  • Kim, Sung-Hyun (Department of Chemical and Biological Engineering, Korea University)
  • Published : 2005.06.01

Abstract

Electroluminescence(EL) and current-voltage(I-V) characteristics of hybrid EL devices containing Pr and Mn co-doped ZnS nanoparticles were investigated in this study. For the insertion of a hole transport layer of poly (N-vinyl carbazole)(PVK), the current level became lower due to the accumulation of electrons at the interface between PVK and nanoparticles. When both PVK and buffer layer $BaF_2$ were simultaneously introduced, the enhanced EL efficiency and improved I-V characteristics were obtained. This results from the additional increase of hole injection owing to the internal field induced by the significant accumulation of electrons at the interface. The presence of buffer layer $BaF_2$ together with PVK makes it possible the charge accumulation enough to induce the sufficient internal field for further hole injection.

Keywords

References

  1. S. Coe-Sullivan, W. Woo, J. S. Steckel, M. Bawendi, and V. Buloric, 'Tuning the performance of hybrid organic/inorganic quantum dot light-emitting devices', Organic Electronics, Vol. 4, No. 2-3, p. 123, 2003
  2. H. Yang, P. H. Holloway, and B. B. Ranta, 'Photoluminescent and electroluminescent properties of Mn-doped ZnS nanocrystals', J. Appl. Phys., Vol. 93, No.1, p. 586, 2003
  3. R. A. M. Hikmet, D. V. Talapin, and H. Weller, 'Study of conduction mechanism and electroluminescence in CdSe/ZnS quantum dot composites', J. Appl. Phys., Vol. 93, No.6, p. 3509, 2003
  4. L. Brus, 'Electronic wave functions in semiconductor clusters: Experiment and theory', J. Phys. Chem., Vol. 90, No. 12, p. 2555, 1986
  5. M. C. Schlamp, X. Peng, and A. P. Alivisatos, 'Improved efficiencies in light emitting diodes made with CdSe/CdS core/shell type nanocrystals and a semiconducting polymer', J. Appl. Phys., Vol. 82, No. 11, p. 5837, 1997
  6. K. Sooklal, B. S. Cullum, S. M. Angel, and C. J. Murphy, 'Photophysical properties of ZnS nanoclusters with spatially localized $$Mn^{2+}$$' , J. Phys. Chem., Vol. 100, No. 11, p. 4551, 1996 https://doi.org/10.1021/jp951835c
  7. S. A. Crooker, J. A. Hollingsworth, S. Tretiak, and V. I. Klimov, 'Spectrally resolved dynamics of energy transfer in quantum-dot assemblies: Towards engineered energy flows in artificial materials', Phys. Rev. Lett., Vol. 89, No. 18, p. 186802-1, 2002