Abstract
In this work, a method was developed to determine the concentration of Eu3+ and Tb3+ ions in a thin-film sample of SiO2, co-doped with ZnO-nanocrystals (ZnO-nc), to produce a sample of any desired colour in the International Commission on Illumination (CIE) colour space. Using this method, a white light emitting sample was fabricated. The thin-film sample combines red, green and blue emissions from the Eu3+ ions, Tb3+ ions and ZnO-nc, respectively, to create white light or light of any desired colour. The emissions at 614 nm and 545 nm from Eu3+ and Tb3+ ions, respectively, is due to the energy transfer from the excited ZnO-nc to the rare-earth (RE) ions. In this way, only a single excitation wavelength is needed to excite the ZnO-nc, Eu3+ and Tb3+ ions in the sample to produce emission of a desired colour from the sample. We developed an empirical 4th-degree polynomial equation to determine the concentrations of Eu3+ and Tb3+ ions to produce light of any desired colour in the CIE colour space. Based on the above empirical equation, the concentration of Eu3+ and Tb3+ ions for a white light emitting sample was found to be 0.012 and 0.024 molar fractions, respectively. The white light emission from the sample was confirmed by fabricating the sample using the low-cost sol–gel process. The stimulated emission spectra and the experimental emission spectra of the white light sample fit very well. The results presented in this work are important to develop energy efficient solid state lighting devices.
Highlights
In recent years, white light emitting diodes have been widely studied [1,2,3,4,5] and developed for various solid state lighting applications
The results presented in this work are important to develop energy efficient solid state lighting devices
We present a simple way to produce white light from thin-film samples containing semiconductor nanocrystal and lanthanide rare-earth (RE) ions
Summary
White light emitting diodes have been widely studied [1,2,3,4,5] and developed for various solid state lighting applications. White light emitting diodes play an important role in applications, such as in displays, general lighting and automobile headlights. In most of these applications, the white light is produced either through i) a phosphor conversion ion in which a ultra-violet(UV)-blue light emitting diode (LED) is used along with a yellow phosphor or through ii) a combination of red, green and blue (RGB) LEDs [2]. We present a simple way to produce white light from thin-film samples containing semiconductor nanocrystal and lanthanide rare-earth (RE) ions. The UV-blue emission from zinc oxide nanocrystals (ZnO-nc) is combined with the red and green emissions from the RE ions, such as Europium (3+) and Terbium (3+), respectively, to produce white light. An advantage of using ZnO-nc, Eu3+ and Tb3+ ions to produce white light is that a thin-film sample of these materials embedded in
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
