Taiwan scientists developed a bright future of Zinc Oxide LED

Scientists in Taiwan have recently developed a white light emitting diode (LED) with Zinc Oxide (ZnO) / blue light organic composite film. They succeeded in the growth of inorganic ZnO nanorod arrays (nanorod) on blue organic light-emitting films by hydrothermal method (hydrothermal method). This technology is different from the traditional LED epitaxial growth mode, not only the method is simple and the whole process of low temperature, for the future development of white light source attractive.

General white light-emitting diodes can be divided into two types of inorganic and organic. The past production of white light emitting components should be considered inorganic material lattice matching problem, process equipment and the need of high vacuum and high temperature, so the manufacturing cost is high; and the white organic light emitting components require expensive and complicated chemical reaction in the development of white light materials, if the white component consists of three layers of RGB organic materials, also need to concerns about the intensity of luminescence and the life of the inconsistency of the different layers of material.

Luminescent Nanocomposites

National Taiwan University professor Lin Qingfu and photoelectric doctoral student Li Junyu, by solution process technology of low temperature, the N type inorganic ZnO nanowire arrays and P blue materials successfully integrated into PN type light emitting diode, the inorganic / organic composite films have ZnO high carrier mobility and migration advantages, the benefits of organic materials the fluorescence efficiency and large-area fabrication, no matching problems of different materials lattice, does not need to use expensive vacuum equipment and high temperature.

According to Professor Lin Qingfu's laboratory, ZnO nano column will produce bonding with the organic film in the growth process, and the generation of Zn (OH) 2, this is caused by the source of Zinc Oxide surface light, so when the component is biased, electron hole pairs easily between ZnO composite nano column surface / organic interface. Photon emission wavelength Zinc Oxide covering a large number of surface defects and blue organic materials luminescence wavelength, so white.

The team used Fourier transform infrared spectrometer (Fourier-Transform Infrared, Spectrometer, FTIR) observed that the spectrum produced by hydrothermal method ZnO/ blue organic composite films have a strong peak at 3410 cm-1 corresponding to the hydroxyl group of the film, that actually contains a lot of Zn (OH) 2.