One-Pot Synthesis of Highly Luminescent Bimodal Alloyed [Cd1-xZnxSe1-ySy] Quantum Dots for Application in White Light Emitting Diodes

高效率雙峰分佈合金[Cd1-xZnxSe1-ySy]量子點之直接合成及其白光發光二極體之應用

洪竟哲(Ching-Che Hung)

指導教授 ： 陳學仕 ； 黃金花

國立清華大學/工學院/材料科學工程學系/碩士(2016年)

摘要

本論文提出首次以化學溶液反應法直接合成高效率雙峰分佈合金[Cd1-xZnxSe1-ySy]量子點，在一般的合成過程中，先將硒前驅物注入至高溫之鎘前驅物與鋅前驅物，合成雙峰分佈合金[Cd1-xZnxSe]核種，再注入硫前驅物，使雙峰分佈之核種進一步成長、進行殼層包覆，最後得到高效率雙峰分佈合金[Cd1-xZnxSe1-ySy]量子點。此外，雙峰分佈合金量子點之光致發光(PL)相對強度可藉由改變初始硒前驅物的注射量來控制，而雙峰分佈合金量子點之各別尺寸大小能利用不同硫前驅物之注入時間來控制。本論文也提出一合理之成長機制來解釋雙峰分佈合金量子點之製備及其性質之調控，我們以擁有特定大小或結構之奈米粒子被侷限於化學位能井的概念來解釋實驗中所觀察到的現象，並以一系列的實驗來證實化學位能井的存在以及其對於合成雙峰分佈合金量子點之重要性，這一成長模型提供我們進一步研究奈米晶粒成長機制的機會。最後，本論文顯示雙峰分佈合金量子點在白光發光二極體應用上之潛力，結合雙峰分佈合金量子點及藍光發光二極體可輕易製備白光發光二極體，而其色座標、演色性與色域可由改變合成雙峰分佈合金量子點之實驗參數來調控，此方法大大地簡化白光發光二極體之製程，也減少可能由額外的純化步驟或後處理所造成之汙染，因此，雙峰分佈合金量子點在照明和顯示器方面之應用是相當有潛力。

關鍵字

量子點 ； 合金 ； 雙發光 ； 白光發光二極體

並列摘要

We present a one-pot synthetic method to prepare alloyed [Cd1-xZnxSe1-ySy] quantum dots with controllable bimodal size distribution and high quantum efficiency for the first time. In a typical synthesis of bimodal alloyed quantum dots, alloyed [Cd1-xZnxSe] seeds consisting of two size distribution are prepared in the initial stage, followed by incorporation of sulfur precursor which promotes further growth and shelling processes. Finally, the bimodal alloyed [Cd1-xZnxSe1-ySy] quantum dots (QDs) with high quantum yield are obtained. The bimodal wavelength and relative photoluminescence intensity of bimodal QDs are controlled by experimental factors based on the thermodynamics and kinetics. We present that existence of chemical potential well for nanoparticles is a critical parameter to control the characteristics of the bimodal alloyed QDs. Finally, we demonstrate the potential of the as-prepared bimodal alloyed QDs in the application of white light emitting diodes (WLEDs) through coupling them with the blue-light InGaN chips. The color axis, color rendering index, and color gamut of the WLEDs are simply modified via changing the synthetic parameters without any post-mixing procedure. Hence, the fabricating process has been dramatically simplified, and the possible contamination from the purification process and environment may be reduced. The one-pot bimodal alloyed QDs based WLEDs definitely is a promising candidate in the lighting and display applications.

並列關鍵字

quantum dot ； alloyed ； bimodal ； white light emitting diodes

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