Kang Sukhyun, Jeong Young Kyu, Jung Kyung Hwan, Son Yong, Choi Sung-Churl, An Gae Seok, Han Hyuksu, Kim Kang Min
Korea Institute of Industrial Technology Gwahakdanji-ro 137-41 Gangwon-do 25440 Republic of Korea
Korea Institute of Industrial Technology 113-58, Seohaean-ro Siheung-si Geyonggi-do 15014 Republic of Korea.
RSC Adv. 2019 Nov 25;9(66):38447-38453. doi: 10.1039/c9ra07555k.
Graphite is economic and earth-abundant carbon precursor for preparing graphene quantum dots (GQDs). Here, we report a facile and green approach to produce GQDs from graphite flakes a pulsed laser ablation (PLA) method assisted by high-power sonication. A homogeneous dispersion of graphite flakes, caused by high-power sonication during PLA, leads to the formation of GQDs following a laser fragmentation in liquid (LFL) rather than laser ablation in liquid (LAL) mechanism. The final product of GQDs exhibits the distinct structural, chemical, and optical properties of pristine graphene itself. However, graphene oxide quantum dots (GOQDs) with abundant surface oxygen-rich functional groups are readily formed from graphite flakes when high-power sonication is not employed during the PLA process. GQDs and GOQDs show a significantly different luminescence nature. Hence, selective production of either functional GQDs or GOQDs can be achieved by simply turning the high-power sonication during the PLA process on and off. We believe that our modified PLA process proposed in this work will further open up facile and simple routes for designing functional carbon materials.
石墨是制备石墨烯量子点（GQDs）的经济且储量丰富的碳前驱体。在此，我们报道了一种从石墨薄片制备GQDs的简便绿色方法——一种由高功率超声辅助的脉冲激光烧蚀（PLA）方法。在PLA过程中，高功率超声导致石墨薄片均匀分散，这使得在液体中激光碎裂（LFL）而非液体中激光烧蚀（LAL）机制下形成GQDs。GQDs的最终产物展现出原始石墨烯本身独特的结构、化学和光学性质。然而，当在PLA过程中不采用高功率超声时，由石墨薄片很容易形成具有丰富表面富氧官能团的氧化石墨烯量子点（GOQDs）。GQDs和GOQDs表现出显著不同的发光性质。因此，通过在PLA过程中简单地开启和关闭高功率超声，就可以选择性地制备功能性GQDs或GOQDs。我们相信，我们在这项工作中提出的改进PLA工艺将进一步为设计功能性碳材料开辟简便的路线。
