Improved efficiencies in light emitting diodes made with CdSe(CdS) core/shell type nanocrystals and a semiconducting polymer

Schlamp, M. C. ; Peng, Xiaogang ; Alivisatos, A. P.

[S.l.] : American Institute of Physics (AIP)
Published 1997
ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
We report experiments on bilayer light emitting diodes made with organically capped CdSe(CdS) core/shell type semiconductor nanocrystals and an electroluminescent (EL) semiconducting polymer [poly(p-phenylenevinylene) or PPV]. The devices emit from red to green with external quantum efficiencies of up to 0.22% at brightnesses of 600 cd/m2 and current densities of 1 A/cm2. They have operating voltages as low as 4 V and lifetimes under constant current flow of hundreds of hours. Most of these numbers are significant improvements over similar devices made with CdSe nanocrystals. The devices show either nanocrystal-only EL or a combination of nanocrystal and PPV EL, depending on nanocrystal layer thickness. The nanocrystal EL is dependent on nanocrystal size. Some devices show a voltage dependent spectral output. The spectral output is consistent with a field dependent electron range in the nanocrystal layer limited by carrier trapping. © 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL: