應用於白光發光二極體之鈣鈦礦複合材料

Perovskite Composite Materials for White Light Emitting-Diodes

張宇鈞(Yu-Chun Chang)

指導教授 ： 劉如熹

國立臺灣大學/理學院/化學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202101009

摘要

本研究乃藉全固態高溫燒結法，將鈣鈦礦量子點成長於中孔洞材料(Mobil Composite of Matter 41; MCM-41)崩解之空隙中，此方式相較以往須利用大量有機溶劑之熱注射法等合成技術更具綠色製程之特性。所得樣品之穩定性極高，於25°C與100°C來回升降溫放光強度仍保有初始值之84.3%，且於85°C與相對溼度85%之200小時測試下放光強度仍保有初始值之近100%，並可達商業應用之可能。本研究首先藉熱重與差熱之分析，發現MCM-41孔洞材料之可能崩解溫度區間介於475°C與700°C間，且鈣鈦礦前驅物之相變溫度為460°C前等，以整合分析此系統可能之反應溫度區間。藉同步輻射中心光源進行原位(in situ)變溫X光繞射之測試，揭露此複合材料系統實際於高溫反應時之機制為由室溫下為δ-CsPbBr3(Orthorhombic)與CsPb2Br5相，並隨溫度升高時僅保留δ-CsPbBr3相與發現於540°C之上時δ-CsPbBr3熔解。藉熱重分析與高解析穿隧式電子顯微鏡之影像佐證MCM-41藉由崩解將熔化之鈣鈦礦量子點包覆於其中。最終於升溫反應後，經降溫之CsPbBr3@SiO2當中為純相之CsPbBr3生長於其中。本研究亦藉化學調控以獲取最佳之反應溫度與比例。得放光波長為515 nm，半高寬為26 nm，內量子效率為15.5%之綠光樣品。所得之最佳樣品可與商用藍光LED封裝後持續以UV光點亮之長達1,008小時。其與商用之紅色螢光粉亦可進行封裝，並解決傳統綠光鈣鈦礦量子點較難應用於背光白光發光二極體之問題。

關鍵字

鈣鈦礦 ； 複合材料 ； 白光發光二極體

並列摘要

In this study, perovskite quantum dots were grown in the voids of disintegrated mesoporous material (Mobil Composite of Matter 41; MCM-41) by using all-solid-state high-temperature sintering method. The traditional method of hot injection usually requires a large amount of organic solvents. This study aimed to provide a new green synthesis way to obtain stable perovskite composite materials. The stability of the obtained sample was extremely high. The luminous intensity retained 84.3% of the initial value after cyclic heating between 25 °C and 100 °C. Moreover, the luminous intensity retained 100% of the initial value under severe test at 85 °C and 85% relative humidity after 200 h. These results indicated the possibility of commercial application. This study initially used thermogravimetric and differential thermal analyses and found that the possible disintegration temperature range of MCM-41 porous material was between 475 °C and 700 °C, and the phase-transition temperature of the perovskite precursor was lower than 460 °C. We then analyzed the possible reaction temperature range of this system. In situ variable temperature X-ray diffraction test was performed using a synchrotron radiation-center light source for the first time. Results revealed that the actual mechanism of the composite material system during the high-temperature reaction was from δ-CsPbBr3 (orthorhombic) and CsPb2Br5 phases at room temperature. With increased temperature, only the δ-CsPbBr3 phase remained and δ-CsPbBr3 was found to melt above 540 °C. Using thermogravimetric analysis and high-resolution tunneling electron microscopy images, we proved that MCM-41 disintegrated the molten perovskite quantum dots in it. Finally, after the high-temperature reaction, the pure phase of CsPbBr3 among the cooled CsPbBr3@SiO2 grew in it. This study also used chemical control to determine the optimum reaction temperature and ratio. A green light sample with a wavelength of 515 nm, an FWHM of 26 nm, and an internal quantum efficiency of 15.5% was obtained. The best sample prepared can be packaged with a commercial blue light-emitting diode (LED) and continuously lit with UV light for up to 1,008 h. It can also be packaged with commercial red phosphors to address the difficulty in using traditional green-light perovskite quantum dots for backlight white LEDs.

並列關鍵字

Perovskite ； Composite Materials ； White Light Emitting-Diodes

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