本文選題：LuAG:Ce　切入點：熒光粉　出處：《山東大學(xué)》2017年碩士論文

【摘要】：能源和環(huán)境一直是制約社會發(fā)展的重要因素,半導(dǎo)體白光LED因其節(jié)能、環(huán)保、高效、響應(yīng)快、壽命長等優(yōu)勢,被稱為二十一世紀(jì)的綠色照明新光源,越來越受到人們的廣泛關(guān)注。Ce摻雜的LuAG(Lu3Al5O12)黃色熒光粉具有較高的量子效率和良好的熱穩(wěn)定性等優(yōu)點,是一種潛在的可用于藍(lán)光芯片激發(fā)型白光LED的高效熒光粉,但是目前Ce摻雜的LuAG熒光粉面臨著制備工藝復(fù)雜、顆粒分散性差、發(fā)光效率低、紅光成分缺失等缺點。本論文采用微波燃燒技術(shù)合成了 Ce摻雜的LuAG納米熒光粉,系統(tǒng)研究了制備技術(shù)對LuAG:Ce熒光粉的微觀結(jié)構(gòu)和光學(xué)性能的影響;研究了 Sm,Pr,Eu,Cr分別摻雜的LuAG熒光粉的光譜性能;系統(tǒng)研究了 Sm,Pr,Eu,Cr分別與Ce共摻雜LuAG黃色熒光粉的光學(xué)性能。具體研究內(nèi)容如下:以 Lu_2O_3、HNO_3、Al(NO_3)3·9H2O、Ce(NO_3)3·6H2O、甘氨酸等為主要原料,采用微波輔助溶液燃燒法制備了 Ce摻雜的LuAG黃色熒光粉。研究結(jié)果表明:950℃煅燒后,粉體呈現(xiàn)單一立方相結(jié)構(gòu),晶粒大小在20～30 nm范圍內(nèi),粒度分布均勻。熒光粉的激發(fā)光譜包含348 nm和445nm處的兩個激發(fā)帶,說明熒光粉可以被藍(lán)光有效激發(fā);發(fā)射光譜是從460 nm跨越到650 nm的不對稱寬發(fā)射帶,發(fā)射峰在505 nm附近。當(dāng)金屬離子與甘氨酸的比例為1:0.5時,粉體表面雜質(zhì)和缺陷少,發(fā)光強度最高。當(dāng)Ce~(3+)的摻雜濃度在0～3.0mol%范圍內(nèi)時,隨著Ce~(3+)摻雜濃度的不斷增大,發(fā)光強度先增大后減小,同時發(fā)射峰發(fā)生紅移。Ce~(3+)離子的猝滅濃度為1.0mol%,其濃度猝滅機理是電偶極與電偶極之間的相互作用。摻雜3wt%LiF后,熒光粉的結(jié)晶溫度降低至850℃,發(fā)光強度提高了約3.5倍。添加10 mol%(N4)2SO4緩解了粉體的團聚現(xiàn)象,改善了粉體的發(fā)光性能,但(NH4)2SO4的分解消耗了部分熱量,反而提高了 LuAG相的結(jié)晶溫度。采用微波輔助溶液燃燒法制備了不同濃度Sm~(3+),Pr~(3+),Eu~(3+),Cr~(3+)分別摻雜的LuAG熒光粉,研究了熒光粉的光譜性能。LuAG:Sm熒光粉在406nm,418nm和466nm等處有較強激發(fā)峰,最強發(fā)射峰出現(xiàn)在618nm處,Sm~(3+)的猝滅濃度為1.50 mol%;LuAG:Pr熒光粉在451nm,460nm和474nm等處有較強激發(fā)峰,發(fā)射峰位于487nm,564nm和610nm處,其中在610nm發(fā)射處Pr~(3+)的猝滅濃度為0.50 mol%;LuAG:Eu熒光粉在382nm,394nm和466nm等處出現(xiàn)較強激發(fā)峰,發(fā)射峰位于 592 nm,610nm和710nm等處,Eu~(3+)的粹滅濃度10.00mol%;LuAG:Cr熒光粉的激發(fā)峰位于458 nm和575 nm處,發(fā)射峰位于565 nm,677 nm和704 nm處,當(dāng)Cr~(3+)摻雜時,沒有出現(xiàn)明顯的濃度猝滅現(xiàn)象。研究結(jié)果表明,Sm~(3+),Pr~(3+),Eu~(3+),Cr~(3+)四種離子分別摻雜的LuAG熒光粉在藍(lán)光區(qū)域內(nèi)均出現(xiàn)了較強激發(fā)峰,且在橙光和紅光區(qū)域出現(xiàn)了較強的發(fā)射峰,說明熒光粉均可以與InGaN藍(lán)光芯片相匹配,并能發(fā)射橙光和紅光。通過微波輔助溶液燃燒法制備了不同濃度Sm~(3+),Pr~(3+),Eu~(3+),Cr~(3+)分別與Ce~(3+)共摻雜的LuAG熒光粉,其中,在Sm~(3+),Pr~(3+)和Cr~(3+)分別與Ce~(3+)共摻雜的LuAG熒光粉的發(fā)射光譜中,除了有Ce~(3+)離子的黃色特征發(fā)射峰外,在618nm,610nm和704 nm等處分別出現(xiàn)了Sm~(3+),Pr~(3+)和Cr~(3+)離子的特征發(fā)射峰。Ce~(3+)和Sm~(3+),Pr~(3+),Cr~(3+)之間存在以非輻射躍遷方式為主的能量傳遞,能量從Ce~(3+)的5d激發(fā)態(tài)分別傳遞給Sm~(3+)的4G5/2能級、Pr~(3+)的3P0能級和Cr~(3+)的4T2g能級。Sm~(3+),Pr~(3+)和Cr~(3+)離子的共摻雜增強了熒光粉的橙光和紅光發(fā)射,降低了熒光粉的色溫,當(dāng)Sm~(3+),Pr~(3+)和Cr~(3+)離子的摻雜濃度分別為3.0 mol%,1.0 mol%和1.0 mol%時,熒光粉的色溫降低幅度最大,分別從7221.94K降低至6772.77K,6837.40K和6785.31K。Eu~(3+)離子的摻雜雖然也增加了紅光發(fā)射,但是使Ce~(3+)離子出現(xiàn)了嚴(yán)重的發(fā)光猝滅。本文采用微波輔助溶液燃燒法,簡單高效地合成了顆粒分布均勻的稀土離子摻雜LuAG納米熒光粉。通過改善制備工藝,增強了熒光粉的發(fā)光強度,同時通過離子共摻雜彌補了紅光成分的缺失,降低了熒光粉的色溫,所制備的熒光粉在發(fā)展高效高顯色白光LED照明光源等方面有著潛在的應(yīng)用前景。
[Abstract]:Energy and environment is an important factor that restricts the development of society, semiconductor white light LED because of its energy saving, environmental protection, high efficiency, fast response, long life and other advantages, known as the green lighting a new light source in twenty-first Century, more and more people pay close attention to.Ce doped LuAG (Lu3Al5O12) yellow phosphor with high quantum efficiency and good thermal stability and other advantages, is a potential for blue chip excited white LED efficient fluorescent powder, but the current LuAG phosphors doped Ce facing complex preparation technology, particle dispersion, low luminous efficiency, lack of defects such as red component. This paper adopted microwave combustion LuAG nano phosphor Ce doped synthesis technology, studied the preparation technology of LuAG:Ce phosphor microstructures and optical properties; research of Sm, Pr, Eu, spectral properties of LuAG phosphor Cr doped; The system of Sm, Pr, Eu, Cr and Ce respectively. The optical properties of Co doped LuAG phosphors. The specific contents are as follows: Lu_2O_3, HNO_3, Al (NO_3) 3 - 9H2O, Ce (NO_3) 3 - 6H2O, glycine as the main raw materials, LuAG yellow phosphors doped with Ce were prepared by microwave assisted solution combustion method. The results showed that: 950 the calcined powder after a single cubic phase structure, grain size in the range of 20~30 nm, uniform particle size distribution. The excitation spectra of phosphors containing two nm and 348 445nm excitation band that phosphor can be effectively excited blue light emission; the spectrum is from 460 nm to 650 nm asymmetry across the broad emission band, the emission peak near 505 nm. When the metal ion and the proportion of glycine was 1:0.5, the surface of powder impurities and defects, the highest luminescence intensity. When Ce~ (3+) doping concentration in the range of 0 ~ 3.0mol%, with Ce~ (3+) doping Increasing the concentration of luminous intensity increases first and then decreases, while the red shift of emission peak of.Ce~ (3+) ion concentration quenching was 1.0mol%, the concentration quenching mechanism is the interaction between dipole and dipole. After doping 3wt%LiF, the crystallization temperature of the phosphor is reduced to 850 DEG C, the luminescence intensity is increased by about 3.5 times 10. Add mol% (N4) 2SO4 to ease the agglomeration of powder and improve the luminescent properties of the powder, but the decomposition of 2SO4 (NH4) part of the heat consumption, but increased the crystallization temperature of LuAG phase. Different concentrations of Sm~ were prepared by microwave assisted solution combustion (3+), Pr~ (3+) Eu~, (3+), Cr~ (3+) LuAG phosphors were doped, studied the spectral properties of.LuAG:Sm phosphor fluorescent powder in 406nm, 418nm and 466nm have strong excitation peaks, the strongest emission peak appeared at 618nm, Sm~ (3+) of the quenching concentration for 1.50 mol%; in LuAG:Pr phosphor 451nm, 460nm 鍜，

本文編號：1652966