A white light emitting diode made of ZnO nanorods and a blue LED

2^nd International Conference and Exhibition on Materials Science & Engineering

October 07-09, 2013 Hampton Inn Tropicana, Las Vegas, NV, USA

SachindraNath Sarangi, Shinji Nozaki, SurendraNath Sahu, Noriyuki Sugiyama and Kazuo Uchida

Accepted Abstracts: J Material Sci

Abstract :

The white light-emitting diodes (LEDs) have drawn much attention to replace conventional lighting sources because of low energy consumption, high light efficiency and long lifetime. Although the most common approach to produce white light is to combine a blue LED chip and a yellow phosphor, such a white LED cannot be used for a general lighting application, which requires a broad luminescence spectrum in the visible wavelength range. We have successfully chemically synthesized the ZnO nanorods showing intense broad luminescence in the visible wavelength range and made a white LED using the ZnO nanorods as phosphor excited with a blue LED. Their lengths and diameters were 2-10 μm and 200-800 nm, respectively. The wurtzite structure was confirmed by the x-ray diffraction measurement. The PL spectrum obtained by exciting the ZnO nanorods with the He-Cd laser has two peaks, one associated with the near band-edge recombination and the other with recombination via defects. The peak intensity of the near band-edge luminescence at 388 nm is much weaker than that of the defect-related luminescence. The latter luminescence peak ranges from 450 to 850 nm and broad enough to be used as a phosphor for a white LED. A white LED has been fabricated using a blue LED with 450 nm emission and 1.0 mg of ZnO nanorod powders. The LED performances show a white light and the Commission Internationale de 1'Eclairage (CIE) chromaticity color coordinates of 450 nm. LED pumped white emission shows a coordinate of (0.30, 0.36) for an optimum composition.

Biography :

SachindraNath Sarangi completed his Ph.D. from Jadavpur University, Kolkata in the year 2007 and pursuing his postdoctoral studies at the University of Electro-Communications, Tokyo under JSPS fellowship program. Prior to this postdoc position, he was a scientific officer at Institute of Physics, Bhubaneswar, India. His research interests focus on nanostructured materials for different applications. He has published more than 56 papers in reputed journals and has been serving as reviewer for many international journals.