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標題: | 高效率無稀土螢光材料及微螢光陣列之應用 High Efficiency Rare-earth-free Fluorescent Materials and their Application for Fluorescent MicroArrays |
作者: | Jyun-Yu Lin 林峻宇 |
指導教授: | 林清富(Ching-Fuh Lin) |
關鍵字: | 無稀土,有機染料,白光LED,抬頭顯示器,微發光二極體, non-rare-earth-element,organic dye,white LED,head up display,micro LED, |
出版年 : | 2018 |
學位: | 碩士 |
摘要: | 現今白光LED之螢光粉主要是以稀土材料做為開發與製作,然而稀土材料的開採與提煉之過程,對於環境及人類有相當大的迫害與影響。因此,對螢光材料而言,要研發出無稀土之高效率發光材料,以成為世人們科學研究與改進的目標。
本論文研究之第一部份,系以有機染料作為發光主體,其特點為無稀土也不含重金屬元素,非常符合我們用來製作螢光粉的基本條件,此外,我們在篩選有機染料會以高共軛鍵結與具備發色團之結構來挑選,我們將Rhodamine 6G、Coumarin 6及DCM2有機染料溶於各自適合之溶劑後,使各螢光溶液在藍光LED激發下能各自激發出橘色、綠色及紅色之放光。接者我們再將各螢光溶液添加沉膜聚合物PVP,使其將有機染料分子包覆,並能將螢光溶液之放光性質在乾燥加熱後完整保留,乾燥加熱後的螢光粉塊經簡易的研磨,便可得到各顏色之螢光粉。我們所自製之橘色、綠色及紅色螢光粉,分別在藍光LED激發下,量子產率可達到73 %、87.7 %及80.4 %。 第二部份,我們將自製之螢光粉分別以單色、雙色及三色配合藍光LED激發來混光,而單色螢光粉混出之白光其色溫通常偏低或高,演色性也不佳,因此嘗試以雙色(綠色及紅色)混光,在演色性表現上提升許多,可提升至86.0 Ra,若在雙色粉體中加入微量的橘色螢光粉,混出之白光更加接近自然白光性質,演色性可達到89.5 Ra,色溫5406 K。另外,我們將DCM2及PVP溶入二氯甲烷後得到之高效率紅光溶液,旋塗沉膜於透明塑膠基板上,目前可應用在抬頭顯示器的部分。與商用的反射式顯示膜相比,我們自製的螢光顯示膜具有高穿透、亮度高及不會有視場角上之限制,此外,螢光顯示膜是以光致發光來顯示,所以不會有反射影像的干擾,對於要應用在各式透明基板上或大面積製作有研發的潛力與商機。 最後章節中,我們提出以高效率無稀土溶液來製作微螢光陣列,可應用在微發二極體上。目前微發二極體仍有轉移量率的門檻有待突破,然而,我們所提出的做法是將螢光膜旋塗沉膜於基板上再經黃光微影及兩道反應離子蝕刻,即可製作出微螢光陣列。我們的螢光膜相較於量子點的優勢為,旋塗沉膜後較均勻並且於大氣下不易變質等,從電子顯微鏡剖面圖可看出完整方形輪廓及以藍光光源激發可看出方形綠光的激發光產生,並且也嘗試以微發光二極體試片上製作為螢光陣列,初步點測結果可於綠光波段觀察到明顯的波形,對於作為微發二極體之轉換層是非常具有研發潛力的。 Nowadays, the fluorescence for white LED is mainly developed and produced by rare-earth materials. However, the process of mining and refining rare-earth materials has caused considerable persecution and impact on the environment and human beings. Therefore, for fluorescent materials, high-efficiency luminescent materials without rare -earth-elements should be developed. It is the goal for scientific research and improvement for fluorescent materials. The first part of the research is based on organic dyes as the host of luminescence. It features no rare-earth-element and no heavy metal according to the basic concepts we use to make fluorescent powder. In addition, we choose organic dyes which possess high conjugate bond and chromophore structure. We dissolve Rhodamine 6G, Coumarin 6 and DCM2 organic dyes in their respective solvents, so each fluorescence solution can be excited by the blue LED and generate orange, green and red light. In addition, we add the film-forming polymer PVP to each fluorescent solution to clad the organic dye molecules. Also, the fluorescent solution lighting properties can maintain after drying and heating. With a simple grinding, we can get the fluorescence powder of each color. In addition, the orange, green and red fluorescing powders have quantum yields of 73%, 87.7% and 80.4%, respectively, under the excitation of blue LEDs. In the second part, the homemade fluorescence powder of a single color, two color and three color with blue LED excitation. At first, blue light mixed with single fluorescence powder usually has a low or high color temperature and poor color rendering. Second, blue light mixed with two colors fluorescence powder (green and red) could enhance a lot of color rendering, which is 86.0 Ra. Finally, we add the orange fluorescent powder into the two-color powder. The property of mixed white light is close to natural white light which color rendering can reach 89.5 Ra and color temperature is 5406 K. Besides, by dissolving DCM2 and PVP into dichloromethane, which has high quantum efficiency. Then, by spin coating the DCM2 solution on the transparent plastic substrate which can be applied to the head-up display. Compared with the commercial reflective display film, the homemade fluorescent display film has high penetration, brightness and no limitation on the angle of view. In addition, the fluorescent display film is based on photoluminescence, so there is no interference from reflected images. Futhermore, fluorescent display film possess potential and business opportunities for research and development on various transparent substrates or large-area production. In the final part, by fabricating micron-fluorescent arrays with high efficiency rare earth-free solutions that can be applied to micro-LED. However, there is still a threshold for the transfer rate of micro-LED. The method is to spin the fluorescent film on the substrate and then use photolithography and two circuit of RIE to make the micron fluorescent array. From cross-section view of the electron microscope can be seen the complete square outline and the excitation of the green light can be seen by the excitation of the blue light source. Also, by making the fluorescent array on the micro-LED and the result of measurement has the green light emission peak, which is very promising for the conversion layer as a micro-LED. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/78926 |
DOI: | 10.6342/NTU201803888 |
全文授權: | 有償授權 |
電子全文公開日期: | 2023-08-23 |
顯示於系所單位: | 光電工程學研究所 |
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