【摘要】：光子晶體作為一種納米尺度的材料,自從其被提出以來這種有序的具有孔洞結構的周期性材料就備受關注。光子晶體具有光子帶隙和光子局域等特性,可以調制材料的發(fā)光性能,在光催化、太陽能、檢測、激光、顯示等方面具有巨大的應用潛力。本文以溶膠-凝膠法制備了稀土摻雜的Bi2WO6納米粉和Ba TiO3反蛋白石光子晶體,并對其上轉換發(fā)光性能進行了研究,具體如下:(1)以檸檬酸(CA)和乙二胺四乙酸(EDTA)作為螯合劑,采用溶膠-凝膠法制備Bi2WO6:Yb3+,Tm3+前驅體溶膠,通過調節(jié)螯合劑的用量得到當Bi2WO6:EDTA:CA=1mol:2mol:0mol時能夠獲得流動性較好的前驅體溶膠,并且經(jīng)過450℃,4h燒結能夠制得純相的鎢酸鉍納米粉。制備了Yb3+,Tm3+摻雜比例分別為4%:1%、6%:1%、8%:1%、10%:1%的Bi2WO6:Yb3+,Tm3+納米粉。在980nm紅外光激發(fā)下得到455nm、480nm、656nm和686nm上轉換發(fā)光,對比發(fā)現(xiàn):當Yb3+,Tm3+的摻雜濃度為Yb3+:Tm3+=6%:1%時,Bi2WO6:Yb3+,Tm3+納米粉的發(fā)光最強,并對其上轉換發(fā)光機制進行了研究,分別對應1D2→3F4(455nm)、1G4→3H6(480nm)、1G4→3F4(656nm)以及3F2→3H6(686nm)能級躍遷過程。(2)采用流速可控垂直沉積自組裝(FCVD)法制備三維聚苯乙烯(PS)蛋白石光子晶體,溶膠-凝膠方法制備BaTiO3:Yb3+,Er3+,Tm3+前驅體溶膠,通過旋涂法將BaTiO3:Yb3+,Er3+,Tm3+前驅體溶膠填充到PS蛋白石光子晶體的空隙中,室溫陳化24h后進行高溫煅燒以去除PS微球,最后得到帶隙分別位于470nm和635nm的純相的BaTiO3:Yb3+,Er3+,Tm3+反蛋白石光子晶體(IOPC),分別標記為IOPC1和IOPC2。采用980nm激光激發(fā)樣品,Tm3+發(fā)出480nm的光,Er3+發(fā)出525nm、550nm和660nm的光。比較反蛋白石樣品與無序樣品發(fā)現(xiàn):在IOPC1中,480nm的藍光自發(fā)輻射與光子帶隙重疊,藍光發(fā)射受到了抑制,而525nm、550nm的綠光得到了增強。激發(fā)過程的研究表明:由于光子帶隙對自發(fā)輻射的抑制作用,藍光480nm(Tm3+:1G4→3H6)減弱,進而導致能量逆?zhèn)鬟f(EBT)過程:1G4(Tm3+)+4I15/2(Er3+)→3F4(Tm3+)+4F9/2(Er3+)增強,隨后通過交叉馳豫(CR)過程:24F9/2→4I11/2+2H11/2/4S3/2+聲子能量導致Er3+在能級2H11/2和4S3/2的布居增多,525nm和552nm的綠光發(fā)射增強。在光子帶隙為635nm的IOPC2中,660nm自發(fā)輻射與光子帶隙部分重疊,抑制了660nm的上轉換發(fā)光,能量傳遞(ET):4F9/2(Er3+)+3F4(Tm3+)→4I15/2(Er3+)+1G4(Tm3+)就會增強,進而1G4的布居增多,480nm發(fā)光增強,同時,CR:4F9/2+4I13/2→4S3/2+4I15/2+聲子能量也會增強,Er3+在能級4S3/2的布居增多,552nm的綠光發(fā)射增強。
[Abstract]:As a nanoscale material, photonic crystals have attracted much attention since they were proposed. Photonic crystals with photonic bandgap and photonic localization can modulate the luminescent properties of materials and have great application potential in photocatalysis, solar energy, detection, laser, display and so on. In this paper, rare earth doped Bi2WO6 nano-powders and Ba TiO3 opal photonic crystals were prepared by sol-gel method, and their up-conversion luminescence properties were studied. The main contents are as follows: (1) Bi2WO6:Yb3, Tm3 precursor sol was prepared by sol-gel method with citrate (CA) and ethylenediamine tetraacetic acid (EDTA) as chelating agents. The precursor sol with good fluidity can be obtained by adjusting the amount of chelating agent, and the pure bismuth tungstate powder can be prepared by sintering at 450 鈩，

本文編號：2400191