Charge transfer effects in graphene-CdSe/ZnS quantum dots composites

Alexander V. Klekachev; Inge Asselberghs; Sergey N. Kuznetsov; Mirco Cantoro; Jeong Hun Mun; Byung-Jin Cho; Jun-ichi Hotta; Johan Hofkens; Marleen van der Veen; André L. Stesmans; Marc M. Heyns; Stefan De Gendt

doi:10.1117/12.930082

27 September 2012 Charge transfer effects in graphene-CdSe/ZnS quantum dots composites

Alexander V. Klekachev, Inge Asselberghs, Sergey N. Kuznetsov, Mirco Cantoro, Jeong Hun Mun, Byung-Jin Cho, Jun-ichi Hotta, Johan Hofkens, Marleen van der Veen, André L. Stesmans, Marc M. Heyns, Stefan De Gendt

Author Affiliations +

Proceedings Volume 8462, Carbon Nanotubes, Graphene, and Associated Devices V; 84620L (2012) https://doi.org/10.1117/12.930082
Event: SPIE NanoScience + Engineering, 2012, San Diego, California, United States

Abstract

Graphene possesses unique physical properties, due to its specific energy bands configuration, substantially different from that of materials traditionally employed in solid-state optoelectronics. Among the variety of remarkable properties, strong field effect, high transparency in the visible-light range and low resistivity of graphene sheets are the most attractive ones for optoelectronic applications. Zero-dimensional colloidal semiconductor nanocrystals, known as quantum dots (QDs), attract immense attention in the field of photonics due to their size-dependent tunable optical properties. By combining these two types of nanomaterials together, we demonstrate the role of graphene as an efficient charge transfer medium from- and to II-VI quantum dots. The optical excitation of II-VI quantum dots dispersed on single layer graphene results in an electron transfer from the nanocrystals to graphene. This is evidenced from photoluminescence imaging and confirmed by the electrical measurements on QDs-decorated single layer graphene field effect transistors (SLG-FET). In the second part of this paper we demonstrate an efficient hole injection from graphene into QDs-layered nanocrystalline structures and the operation of the corresponding graphene-based quantum dot light emitting diodes (QD-LED). We also benchmark graphene vs. indium-tin-oxide (ITO) based QD-LEDs in terms of device electroluminescence intensity performance. Our experimental results show better hole injection efficiency for graphenebased electrode at current densities as high as 200 mA/cm² and suggest single layer graphene as a strong candidate to replace ITO in QD-LED technology.

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Alexander V. Klekachev, Inge Asselberghs, Sergey N. Kuznetsov, Mirco Cantoro, Jeong Hun Mun, Byung-Jin Cho, Jun-ichi Hotta, Johan Hofkens, Marleen van der Veen, André L. Stesmans, Marc M. Heyns, and Stefan De Gendt "Charge transfer effects in graphene-CdSe/ZnS quantum dots composites", Proc. SPIE 8462, Carbon Nanotubes, Graphene, and Associated Devices V, 84620L (27 September 2012); https://doi.org/10.1117/12.930082

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