Licensable Technologies : Materials : Energetic

Non-Contact Pumping Of Light Emitters Via Non-Radiative Energy Transfer

Abstract
LANL has developed a novel method for exciting light emission from nanocrystal quantum dots. The technology has many applications ranging from general illumination and displays, to electrically pumped narrow band lasers. The technology uses a non-contact, non-radiative energy transfer from a quantum well to produce light from an adjacent layer of nanocrystal quantum dots. In the past, it has been very difficult to excite these materials electrically because of an insulating layer of organic molecules – this is the technological barrier that LANL has overcome. One embodiment of the method includes using an InGaN quantum well injected with electron-hole pairs and then applying a covering layer of CdSe/ZnS quantum dots. Instead of trying to inject the electrons-hole pairs needed for light emission across the insulating organic layer coating the quantum dots, LANL’s technology uses a non-radiative transfer process known as F�rster energy transfer. When the electron-hole pairs recombine in the quantum well the energy they release is transferred to the quantum dots. This occurs because of the creation of an oscillating electric field, brought about by the annihilation of the electron-hole pairs. This oscillating electric field reaches out to the quantum dots and generates electron-hole pairs that will relax to form excitons. Each electron-hole pair excited in this way produces a photon – providing outstanding efficiency. LANL researchers have demonstrated the enabling effect for optically-pumped quantum dot LEDs that use F�rster energy transfer. The next step towards commercialization is to demonstrate a practical electrically-pumped device.

Application(s)

• General Illumination
• Information Display
• Telecommunications
• Automotive Lighting
• LED Signs

Advantages

• Emission wavelength(s) can be controlled by particle size and by using mixtures of sizes
• Potential enabling method for efficient white light LED
• High efficiency and reduced energy consumption
• Low cost

IP Status: Available for Non-Exclusive Licensing

Reference Number: 317

S Number: DOE reference no.(s): 102,388

Patents & Applications:
Application(s) Filed

Posted: 02-18-2005

Contact
Laura Barber
Technology Transfer Division
Los Alamos National Laboratory
P.O. Box 1663, MailStop C334
(505) 667-9266
ljbb@lanl.gov