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Study on the Photoluminescence Properties of Rare-earth-ions Co-doped Vanadates

Author: YinWenJun
Tutor: MaYongQing
School: Anhui University
Course: Materials Physics and Chemistry
Keywords: White LED Vanadate Codoped
CLC: O614.511
Type: Master's thesis
Year: 2011
Downloads: 34
Quote: 0
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Abstract


As early as 1996, the first generation of white LED has been reported by Ⅲ - Ⅴ semiconductor InGaN chip and a yellow phosphor YAG: Ce package made, InGaN emitting blue light, YAG: Ce absorb some of the blue light and emit yellow, then yellow emit white light and blue light mixed. Such a semiconductor LED chip prepared in the coating powders of the white LED light source has many advantages, such as good stability, high luminous efficiency, long life, energy losses low. White LED lighting, display and solid-state laser has a very broad application prospects by widespread concern. And, as a fourth-generation light source has been gradually replacing the traditional incandescent and fluorescent lamps. In this article, the author through the pairs in the same matrix (vanadate) incorporation of two kinds of rare earth elements, and the obtained phosphor can emit white light in a single wavelength UV excitation. In device design and fabrication of this phosphor white LED structure has become easier, the costs will be lower, luminous stability will be enhanced. The purpose of this paper is to study the two rare earth element content ratio of luminous intensity. The main content of each chapter are summarized as follows: The first two chapters: first an overview of several models of the white light emission, compared to the traditional thermal radiation, cathode ray and LED light emission, LED has many advantages. Then lists several major white light emission characterization methods. Rare-earth doped vanadate matrix white light emission research progress and preparation methods are summarized. Vanadate matrix double incorporation of rare earth elements to obtain white light is still in its infancy, and study how to get high purity, good color rendering white light is of great significance. Chapter: prepared using traditional solid-phase method Sr2.5DY1/3-xEUxV2O8 (0 ≤ x ≤ 1/3), samples Dy3 yellow red and Eu3 also issued under UV excitation. Moreover, With Eu3 change in the concentration, the intensity of the yellow and red light than the obvious changes, This shows that we can change the Eu3 the concentration to obtain the desired white. In addition, we further in Sr2.5DY1/3-xEUxV2O8 (0 ≤ x ≤ 1/3) incorporating Bi element and found that the incorporation of Bi is conducive to raise the luminous intensity of rare earth elements. Chapter IV: first prepared by solid-phase method Ba3 (1-x) Ce2xV2O8 (0 ≤ x ≤ 0.1) series of samples, found that the strongest emission of x = 0.8 sample Ce. Followed by solid phase prepared the Ba3 (o.92-y) Ceo.16Eu2yV2O8 (0 ≤ y ≤ 0.1) series of samples. Emission spectra, we can observe that the sample also issued Ce3 violet (428nm), blue light (473nm) and red (Eu3 597,618 and 654nm), which show that the matrix able to absorb energy effectively passed to the activator the ion Ce3 and Eu3. And with the increase of the concentration of Eu ions, the luminous intensity of CE3 changed little, from the strongest 160.2 to 116.5, the variation range of only 40. Eu, the emission intensity from the range of 584.7 to 49.36 over 500. So we can be adjusted by adjusting the concentration of the Eu3 the intensity ratio of the blue and red, and thus to obtain the desired white light. Finally, the full text of the summary and outlook.

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CLC: > Mathematical sciences and chemical > Chemistry > Inorganic Chemistry > Metal elements and their compounds > Section Ⅴ group metal elements and their compounds > The vanadium Vice family (Ⅴ B group metal elements ) > Vanadium V
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