Home > Press > Organic light emitting diodes operated by 1.5 V battery
Fig. 1 (a) Schematic of the device structure and the operating mechanism of OLEDs. (b) Chemical structures. CREDIT NINS/IMS |
Abstract:
Various properties of organic light-emitting diodes (OLEDs) have been optimized, including current to photon conversion efficiency. An external quantum efficiency exceeding 20%, with internal quantum efficiency of 100%, has been achieved owing to the development of thermally activated delayed fluorescent and phosphorescent materials that manage the spin of excited states. However, the operating voltage of common types of OLEDs is very high; that of an OLED emitting approximately 600-nm light at a luminance of 100 cd/m2, which is a general display condition, is as high as 4.5 V.
Group of Assistant Professor Seiichiro Izawa and Professor Masahiro Hiramoto at Institute for Molecular Science in Japan, and Associate Professor Masahiro Morimoto and Professor Shigeki Naka at University of Toyama in Japan report that an efficient OLED, operable by a 1.5-V battery, that produces bright emission equivalent to luminance of a typical display. The OLED has a smaller turn-on voltage at 0.97 V than the optical energy of emitted photons at 2.04 eV (608 nm), because the OLED is based on upconversion (UC) transition associated with triplet–triplet annihilation that doubles the energy of excited states (Fig. 1). They reveal that the characteristics of charge transfer (CT) state at the interface are key to efficient UC, and the percentage of excited states deactivated by parasitic loss processes during the UC transition is significantly reduced from over 90% to approximately 10% by introducing a highly crystalline acceptor material and an emissive dopant. Consequently, the UC-OLED reaches 100 cd/m2 at a voltage and emission wavelength of 1.33 V and 608 nm (2.04 eV), respectively (Fig. 2a). This is the lowest operating voltage reported for an OLED that achieves a luminance of 100 cd/m2. It was further demonstrated that the UC-OLED can be operated by a 1.5-V battery to realize luminance of 177 cd/m2 (Fig. 2b).
####
For more information, please click here
Contacts:
Hayao KIMURA
National Institutes of Natural Sciences
Office: 81-354-251-890
Expert Contact
Seiichiro Izawa
Institute for Molecular Science
Office: +81-564-59-5537
Copyright © National Institutes of Natural Sciences
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related Links |
Related News Press |
News and information
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Good as gold - improving infectious disease testing with gold nanoparticles April 5th, 2024
Display technology/LEDs/SS Lighting/OLEDs
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
Light guide plate based on perovskite nanocomposites November 3rd, 2023
Simple ballpoint pen can write custom LEDs August 11th, 2023
Novel design perovskite electrochemical cell for light-emission and light-detection May 12th, 2023
Organic Electronics
Possible Futures
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
With VECSELs towards the quantum internet Fraunhofer: IAF achieves record output power with VECSEL for quantum frequency converters April 5th, 2024
Discoveries
Chemical reactions can scramble quantum information as well as black holes April 5th, 2024
New micromaterial releases nanoparticles that selectively destroy cancer cells April 5th, 2024
Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024
Announcements
NRL charters Navy’s quantum inertial navigation path to reduce drift April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers/Posters
Simulating magnetization in a Heisenberg quantum spin chain April 5th, 2024
Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024
The latest news from around the world, FREE | ||
Premium Products | ||
Only the news you want to read!
Learn More |
||
Full-service, expert consulting
Learn More |
||