Bruhn Benjamin, Brenny Benjamin Jm, Dekker Sidoeri, Doğan Ilker, Schall Peter, Dohnalová Katerina
Van der Waals-Zeeman Institute, University of Amsterdam, Science Park 904, Amsterdam 1098 XH, The Netherlands.
Center for Nanophotonics, AMOLF, Science Park 104, Amsterdam 1098 XG, The Netherlands.
Light Sci Appl. 2017 Jun 30;6(6):e17007. doi: 10.1038/lsa.2017.7. eCollection 2017 Jun.
Silicon nanocrystals (SiNCs) have great potential to become environmental friendly alternatives to heavy-metal containing nanocrystals for applications including medical imaging, lighting and displays. SiNCs exhibit excellent photostability, non-toxicity and abundant resources, but their often reported inefficient and spectrally limited light emission seriously impair their applications. Here we demonstrate a new method that converts SiNCs into an efficient and robust multi-chromatic phosphor. Using ~15 keV electron-beam irradiation of oxide-capped SiNCs, we introduce several types of color centers into the nanocrystal's oxide shell with efficient blue, green and red emission bands, together yielding warm-white photoluminescence, even for a single SiNC. Introduced centers are not native to the original system and we relate them to known defects in silica. Unlike in the silica host, however, here the centers are efficiently optically excitable. Provided further optimization and up-scaling of this method, e-beam irradiated SiNCs can be of great interest as white phosphors for applications such as LEDs.
硅纳米晶体（SiNCs）极有可能成为含重金属纳米晶体的环保替代品，用于医学成像、照明和显示等应用领域。SiNCs具有出色的光稳定性、无毒且资源丰富，但其常被报道的发光效率低下和光谱受限严重阻碍了它们的应用。在此，我们展示了一种将SiNCs转化为高效且稳定的多色磷光体的新方法。通过对包覆氧化物的SiNCs进行约15 keV的电子束辐照，我们在纳米晶体的氧化物壳层中引入了几种类型的色心，这些色心具有高效的蓝、绿和红发射带，即使对于单个SiNC，也能共同产生暖白色光致发光。引入的色心并非原始系统所固有，我们将它们与二氧化硅中已知的缺陷联系起来。然而，与二氧化硅主体不同的是，这里的色心具有高效的光学可激发性。如果对该方法进行进一步优化和扩大规模，电子束辐照的SiNCs作为用于发光二极管等应用的白色磷光体可能会备受关注。
