Sidestepping the selection rules
Article Abstract:
A photon is usually emitted by only 25% of excitons produced when opposite charges on displays using light-emitting diodes meet up. New research has identified a way of obtaining light emission from the other 75% of the excitons. This has the potential to boost the efficiency of organic light-emitting diodes. In the new device, both singlet and triplet excitons transfer energy from a host material. This requires the energy of the exciton to be reduced at each step. A problem at present is the need for a number of downhill energy steps, with the energy of the emitted light thus being much lower than that of the positive and negative charges that link to form the exciton.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2000
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Injecting spin into electronics
Article Abstract:
Two research groups have been able to inject spin-polarized electrons or holes into a light-emitting diode, achieving efficiencies of around 90% and 2%. The diodes emit circularly polarized light in both cases, reinforcing the spin polarization of the carriers. One of the groups demonstrated that voltage-driven spin injection from a semimagnetic to a nonmagnetic semiconductor is extremely efficient, with the device injecting 90% spin-polarized current into a light-emitting diode.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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Spin-dependent exciton formation in conjugated compounds
Article Abstract:
Research is presented describing the study of light-emitting diodes and the injection electrons to form spin state exciton to control the light efficiency.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2001
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