AVS 52nd International Symposium
    Science of Semiconductor White Light Topical Conference Monday Sessions
       Session WL-MoA

Invited Paper WL-MoA5
Color Conversion in Light Emitting Devices using Nonradiative Energy Transfer

Monday, October 31, 2005, 3:20 pm, Room 310

Session: Science of Semiconductor White Lighting
Presenter: M. Achermann, Los Alamos National Laboratory
Authors: M. Achermann, Los Alamos National Laboratory
M.A. Petruska, Los Alamos National Laboratory
S. Kos, Los Alamos National Laboratory
D.L. Smith, Los Alamos National Laboratory
D.D. Koleske, Sandia National Laboratories
V.I. Klimov, Los Alamos National Laboratory
Correspondent: Click to Email
Using modern colloidal chemistry, semiconductor nanocrystals (NCs) can be fabricated with nearly atomic precision in a wide range of sizes and shapes. NCs exhibit high photoluminescence (PL) quantum yields and narrow size-controlled emission lines, and they can easily be manipulated into various two-dimensional (2D) and 3D assemblies. All of these properties make NCs attractive building blocks for applications in various optical technologies including light-emitting devices. One problem associated with realizing NC-based light emitters is that the electrical injection of carriers into NCs is complicated by the presence of the insulating passivation layer. All previous attempts to electrically contact NCs have utilized hybrid inorganic/organic composites comprising conducting polymers. However, the performance of these devices is severely limited by low carrier mobilities in both NC and polymer components and poor polymer stability with respect to photooxidation. Here, we present an alternative, "noncontact" approach to injecting carriers into NCs via nonradiative energy transfer (ET) from a proximal epitaxial quantum well (QW). Monitoring time and spectrally resolved PL dynamics, we observe an efficient energy outflow from the QW, which is accompanied by a complimentary energy inflow into a dense monolayer of NCs assembled on the top of the QW. The measured ET rates are very fast and should allow for the efficient pumping of NCs not only in the spontaneous but also in the stimulated emission regime.