螢光體在水溶液系統中懸浮穩定性之探討

Abstract

螢光體漿體內之粒徑分佈及其穩定性對其噴塗於玻璃基板上的均勻性有很重要的影響。本研究中我們嘗試以球磨法降低螢光體平均粒徑並以polyethylene glycol (PEG)之添加來增加漿體的分散穩定性。實驗結果顯示，經過球磨之後，混合螢光體平均粒徑下降最多，約2.2μm；紅色螢光體平均粒徑下降最少，僅約0.5μm。在使用同重的球磨粒子情況下，小粒徑的球磨粒子越多得到的螢光體平均粒徑越小。在PEG添加量為1.6 wt%時可以得到最小平均粒徑的螢光體，且吸附的PEG量也最大。在添加PEG濃度為0.2~3.2wt%範圍內，隨著PEG量增加，紅、藍螢光體漿體分散穩定性有小幅的成長；對綠色螢光體漿體來說，在PEG濃度為0.8wt%之前，漿體分散穩定性非常好，但PEG濃度為1.6wt%之後，由於高分子架橋現象產生，漿體分散穩定性反而下降。

The performance of the spray of phosphor slurry on glass substrate depends largely upon both its particle size distribution and stability. In this study, ball milling is adopted to reduce the mean particle size of phosphor particles, and polyethylene glycol (PEG） is introduced into a phosphor slurry to improve its stability. The experimental data gathered reveal that the mean particle size of mixed phosphor decreases about 2.6μm after milling, but the reduction in the mean size of red phosphor is less than 0.5μm. For a fixed total mass of milling balls, the larger the ratio (amount of small milling balls/amount of large milling balls) the smaller the mean particle size after milling. The minimum mean particle size and the maximum amount of PEG adsorption occur at 1.6 wt% of PEG. We show that for red phosphor and blue phosphor slurries, although its stability increases with the increase in the PEG dosage, the degree of improvement, however, is limited. For green phosphor slurry, its stability increases considerably when the dosage of PEG is lower than about 0.8 wt%. If the PEG dosage exceeds about 1.6 wt%, due to polymer bridging, the stability declines. In this case, coagulation between particles occurs, and fast precipitation is observed.