Cu2+对碳点的荧光猝灭机理研究
Study of the Mechanism of Quenching Effect of Cu2+ on Fluorescent Carbon Dots
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摘要: 在pH=5.8的Britton-Robinsion(B-R)缓冲溶液中 ,Cu2+ 可有效猝灭 O ,O'-2(3-氨丙基)聚乙二醇1500 (PEG1500N )钝化的碳点荧光 .通过对猝灭机理的研究得出Cu2+对碳点荧光的猝灭是静态猝灭过程 .加入Cu2+ 后 ,碳点的荧光强度和紫外吸收都明显减弱 ,且温度越高猝灭越弱 ,但荧光寿命没有变化 .另外 ,猝灭速率常数 Kq=1013 L/(mol · s)也比典型的溶液中扩散控制猝灭速率常数的上限值高很多 ,这些都证明该过程是静态猝灭过程 .猝灭常数为9.0 × 104 L/mol ,Cu2+与碳点的结合比为6:1 .Abstract: We found in a previous study that fluorescence of PEG 1500N-passivated carbon dots (C-Dots ) could be quenched effectively by copper ions (Cu2+ ) in pH 5.8 Britton-Robinsion (B-R) buffer solution .In the present study ,the quenching mechanism was discussed and a static quenching process was supposed .A significant decrease in UV absorption and fluorescent intensity were found after Cu2+ addition .A smaller amount of quenching was also found at higher temperature .But no change in fluorescence lifetime was de-tected .Additionally ,the Kq value of 1013 L/(mol · s) was larger than the upper limit of typical diffusion-controlled quenching in solution .All of the above results confirmed the view of static quenching .The quenching constant was 9.0 × 104 L/mol ,and the binding ratio of Cu2+ to C-Dots was 6:1 .
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