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Non-Radiative Energy Transfer in Hybrid Organic-Inorganic Semiconductor Structures
Grigorios Itskos 1 , Colin Belton 2 , Martin D Dawson 3 , Ian M Watson 3 , Ray Murray 2 and Donal D.C. Bradley 2
1 Department of Physics, University of Cyprus, Nicosia, Cyprus
2 Department of Physics, Imperial College London, London, United Kingdom
3 Institute of Photonics, University of Strathclyde, Glasgow, United Kingdom
*g.itskos@imperial.ac.uk
Hybrid organic/inorganic semiconductor structures offer the prospect of new devices that can combine the good electrical
properties of inorganic materials with the attractive luminescence properties of organic materials. Consequently, devices
based on dipole-dipole energy transfer from inorganic semiconductors to conjugated polymers can produce highly efficient
emission across the entire visible spectrum.
We have investigated hybrid structures containing InGaN/GaN single quantum wells (QWs) that are spaced from
fluorene-based polymer films by thin cap layers of GaN. Provided their electronic states are matched [1, 2], the close
proximity of the polymer film to the QW promotes efficient non-radiative (Förster) energy transfer, resulting in a strong
visible emission from the hybrid devices. We have also prepared hybrid structures where white light emission is obtained due
to energy transfer from the InGaN/GaN QW to a blend of polyfluorene emitters.
Temperature-dependent spectrally-resolved measurements show that non-radiative energy transfer from the QW to the
polyfluorene film results in a significant enhancement in the organic emission, with as much as a twenty-fold increase over
that resulting from simple radiative energy transfer [3]. Control measurements (without the QW) verify that the intensity
enhancement is due to energy transfer from the UV-light emitting QW rather than any other effect related to the
polymer/GaN cap layer interface. Time-resolved experiments show a significant reduction in the QW decay time providing
further insight into the non-radiative nature of the transfer [4]. In addition, we have verified that non-radiative energy transfer
also occurs from the inorganic well to thin layers of carefully adjusted polymer blends in which cascade non-radiative energy
transfer results in the emission of white light.
[1] D. Basko, G.C. La Rocca, F. Bassani and V.M. Agranovich, Eur. Phys. J. B 8, 353, (1999)
[2] Š. Kos, M. Achermann, V.I. Klimov and D.L. Smith, Phys. Rev. B, 71, 205309, (2005)
[3] G. Heliotis, G. Itskos, R. Murray, M.D. Dawson, I.M. Watson and D.D.C. Bradley, Adv. Materials 18, 334, (2006)
[4] G. Itskos, G. Heliotis, P. G. Lagoudakis, J. Lupton, N.P. Barradas, E. Alves, S. Pereira, I. M. Watson, M. D. Dawson, J.
Feldmann, R. Murray and D. D. C. Bradley, accepted in Phys. Rev. B
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