Title: 新穎銦酸鹽類與鍺酸鹽類螢光體之製成與發光性質之研究
A Study on the Synthesis and Luminescent Properties of Novel Indates and Germanates Phosphors
Authors: 高逢時
Feng-Shih Kao
Teng - Ming Chen
Keywords: 發光;螢光體;銦酸鹽;鍺酸鹽;Luminescence;phosphors;Indate;Germanate;novwl
Issue Date: 2000
Abstract: 本篇論文主要是關於新穎銦酸鹽類與鍺酸鹽類螢光體之製成與發光性質之研究。其中包含:SrIn2O4,CaIn2O4,Zn2GeO4,SrGe2O4及Ca2GeO4等五類螢光體。這些螢光體具有實際應用的潛力。 第一章:發光(Luminescence)簡介。其中包含名詞定義及註解,螢光體的設計簡介,光致發光光譜量測原理以及研究動機。 第二章及第三章:關於新穎場發射式顯示器(FEDs)用螢光體的開發。兩種主體晶格SrIn2O4及CaIn2O4的能隙分別為3.6 eV及3.9 eV,具導電性。傳統螢光體在低電壓使用時、電荷累積的問題可以得到解決。 第四章:闡述Zn2GeO4未被發現的、自身活化的發光特性。它的發光與合成溫度、激發光波長及氫氣氛還原時間有關。文中有深入的探討。 第五章:探討紅光發光主流的Eu3+ 離子,在新穎主體晶格SrGe2O4中的發光特性。其中包含XRD圖譜,光致發光光譜;特別是組態座標圖。另外;文中也收錄以Pr3+及Tb3+離子做為活化劑時、相關的圖譜及圖表。 第六章:研究n S 2 組態離子;也就是Bi3+(6 S 2)離子,在Ca2GeO4晶格的發光現象。多數Bi3+ 活化的螢光體在低溫放射,但本研究中的螢光體在室溫即放射可見光。與稀土離子相較,Bi3+ 離子的發光研究顯得相當稀少且不完整。在本文中,光譜均被詳細標記,並且詳述A帶放射的組態模式;A帶的放射機制以及"不規則放射"的機制。在Bi3+ 螢光體的簡短回顧中;Bi3+ 激發帶的位置,被發現與主體中、未被取代的陽離子的電負度有關。其關連性是第一次被提及。另外;文中也收錄以Eu3+、Pr3+及Tb3+離子做為活化劑時、相關的圖譜及圖表。 第七章:總結論文中螢光體的發光性質。 論文最後是作者的自傳
Several unprecedented inorganic phosphors of indates and germinates have been prepared via solid-state routes and their relevant luminescent properties were investigated in the present research. In the quest for new inorganic phosphors with great potential for modern displays applications and to gain a deeper insight into the luminescence for Pr3+ ( 4 f 2 ), Eu3+ ( 4 f 6 ), Tb3+ ( 6 f 8 ), and Bi3+ ( 6 s 2 ) activators, we have initiated investigations on phosphors with hosts such as semiconducting SrIn2O4 and CaIn2O4, insulating Sr2GeO4 and Ca2GeO4. Furthermore, the luminescence of self-activated Zn2GeO4 was also studied. The configurational coordinate diagrams and band structure for these indates and germanates have been adopted as an illustrative model to rationalize the observed photoluminescence emission and excitation spectra for Eu3+, Pr3+, Tb3+and Bi3+, in particular, the emissions attributed to Eu3+ activated Sr2GeO4 and Ca2GeO4 and Bi3+ activated Ca2GeO4 has been thoroughly analyzed and assigned using band structure model. Furthermore, these new phosphors have been characterized with X-ray diffraction (XRD) for phase identification and structure analysis, photoluminescence (PL) spectra for investigations of luminescent properties, and the diffuse reflectance (DR) spectra to understand energy absorption and band gap energy estimation. In addition, brightness and chromaticity coordinates and diagrams were also measured to characterize the chromaticity under ultraviolet excitation for the phosphors. Our research interests were also extended to a series of self-activated Zn2GeO4 phosphors whose presence and importance may have been overlooked for years in the literature. A mechanism for rationalization of self-luminescence from the host lattice has been proposed. Furthermore, the effects of synthetic conditions (i.e., temperature, atmosphere and duration of reduction), excitation wavelengths and, possibly, oxygen defects present in the host lattice on the luminescence for Zn2GeO4 phases. Consequently, the knowledge established on the basis of results from this work may open the door to the exploratory work into a completely new area in phosphor materials research.
Appears in Collections:Thesis