钾辅助增强CsPbBr3钙钛矿量子点的荧光稳定性及其在QLEDs中的应用

为了提高钙钛矿(CsPbX3,X=Cl,Br,I)量子点的荧光稳定性,实现钙钛矿量子点在下一代平板显示与固态光源中的长期应用,研究了钾元素对量子点荧光性能的影响。首先,采用热注入法合成了CsPbBr3钙钛矿量子点。接着,用油酸钾与上述钙钛矿量子点进行反应,制备了钾元素修饰的钙钛矿量子点。最后,将这些钙钛矿量子点应用于发光二极管的发光层。实验结果表明,当油酸钾的含量为20μL/mL时,钾元素修饰的量子点的荧光性能优于未修饰的量子点。相比于未修饰的量子点所制备的器件,钾元素修饰的量子点所制备器件的最大亮度从1845 cd/m2增加到4300 cd/m2,最大电流效率从0.3 cd/A增加到1.3 cd/A。因此钾元素的引入可以有效地抑制量子点表面缺陷的产生,减少荧光量子产率的损失,增强量子点的荧光稳定性,实现更优越的器件性能。

Potassium-assisted Enhancement of Fluorescence Stability of CsPbBr3 Perovskite Quantum Dots and Their Application in QLEDs

In order to improve the fluorescence stability of perovskite quantum dots(PQDs)(CsPbX3, X=Cl, Br, I) and realize long-term application in the next generation of flat panel displays and solid-state lighting, the effect of potassium on the fluorescence performance of PQDs was studied. First, CsPbBr3 PQDs were synthesized by hot injection method. Then, potassium oleate(KOA) was reacted with the above-objected PQDs to prepare K-modified PQDs(K-PQDs). Finally, these PQDs were applied to the emitting layer of the quantum light emitting diodes(QLEDs). The experimental results show that when the content of KOA is 20 μL/mL, the fluorescence performance of K-PQDs is better than unmodified PQDs. Compared with devices made with unmodified PQDs, the maximum luminance of devices made with K-PQDs increased from 1 845 to 4 300 cd/m2, and the maximum current efficiency increased from 0.3 to 1.3 cd/A. Therefore, the introduction of potassium can effectively suppress the generation of surface defects of PQDs, reduce the loss of photoluminescence quantum yield(PLQYs), enhance the fluorescence stability of PQDs, and achieve more excellent device performance.