Yuan Yun Huan, Liu Ze Xi, Li Rong Sheng, Zou Hong Yan, Lin Min, Liu Hui, Huang Cheng Zhi
Key Laboratory on Luminescence and Real-Time Analytical Chemistry, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
College of Pharmaceutical Science, Southwest University, Chongqing 400716, China.
Nanoscale. 2016 Mar 28;8(12):6770-6. doi: 10.1039/c6nr00402d.
Surface states of carbon dots (CDs) are critical to the photoemission properties of CDs. By carefully adjusting the reaction conditions in a hydrothermal synthesis route, we have prepared a series of CDs with excitation-dependent emission (EDE) and excitation-independent emission (EIE) properties by controlling the content of nitrogen elements, confirming that the characteristic optical properties of CDs originate from their energy levels. It has been found that surface-passivation of the as-prepared CDs by nitrogen doping can improve the emission efficiency and be beneficial to EIE features due to the single electron transition resulting from the single functional groups. And the as-prepared CDs can specifically bind with Hg(2+) with the emission quenched because of the electron transfer from the LUMO levels of CDs to Hg(2+).
碳点（CDs）的表面态对其光发射特性至关重要。通过在水热合成路线中仔细调整反应条件，我们通过控制氮元素含量制备了一系列具有激发依赖发射（EDE）和激发独立发射（EIE）特性的碳点，证实了碳点的特征光学性质源于其能级。研究发现，通过氮掺杂对所制备的碳点进行表面钝化可提高发射效率，并且由于单官能团导致的单电子跃迁，有利于EIE特性。并且所制备的碳点可以与Hg(2+)特异性结合，由于电子从碳点的最低未占分子轨道（LUMO）能级转移到Hg(2+)，导致发射猝灭。
