TE 2011年6月
化学传感器 CHEMICALSENSORS
Vol.31, No. 2 June.2011
ZnS掺Mn磷光量子点对金属离子传感机理的探讨
段玉娇，李文婷，申前进，晋卫军·（北京师范大学化学学院，北京100875）
摘要：合成了以3-殖基丙酸或L-半胱氮酸修饰的水溶性ZnS掺Mn磷光量子点，磷光发射峰在590nm，产生于Mn"的"T-"A，跃迁。磷光信号稳定，不易受溶解氧的影响。检测了七种常见金属离子对磷光性质的影响，结果表明：对于3-巯基丙酸修饰的ZnS:Mn量子点，Cu*,Mn*,Fe*,Co",Pb和Hg离子能有效弹灭其磷光，而Cd离子能增强量子点磷光；对于L-半胱氨酸修饰的ZnS:Mn量子点,Cu*,Mn,Fe*,Co*,Pb*,Hg 以及Cd离子都能有效弊灭其磷光；猝灭方程呈现线性和指数两种形式。通过测量磷光寿命，推断猝灭机理主要为动态筛灭。这些结果为设计具有选择性的基于碑光量子点的离子传感器以及研究响应机理提供了实验和理论的参考。
关键调：ZnS掺Mn量子点；磷光；金属离子；猝灭
PhosphorescentZnSdopedMnquantumdotsforsensingmetalions
andrespondingmechanism
Duan Yu-jiao, Li Wen-ting, Shen Qian-jin, Jin Wei-jun
(College of Chemistry, Beijing Normal University, Beijing 100875, China)
Abstract: Watersoluble Mn** doped ZnS phosphorescent quantum dots (QDs) were prepared using 3 mercapto propionic acid and Lcysteine as stabilizer. Phosphorescent emission peak was at 59Onm which originated from *T,*A, transition of Mn** ions on Zn** sites, and were excited by the energy transferred from the excited electronhole pairs in the ZnS host. Two kinds of QDs were used to detect metal ions, For 3MPA capped quantum dots, the pres-ence of Cu**, Mn,Fe**, Co**, Pb**, Hg** resulted in quenching of phosphorescence while the presence of Cd* result-ed in enhancing of phosphorescence, For Lcysteine capped quantum dots, the presence of Cu**,Mn**,Fe'*, Co**, Pb2+ ,Hg2* and Cd2* resulted in quenching of phosphorescence, By measuring the phosphorescence lifetime, we judged the quenching mechanism was mainly dynamie, The conclusions can provide references for both theory and experiment to design selective ion sensors based on phosphorescent quantum dots.
Key words: ZnS doped Mn quantum dots; phosphorescence; metal ions; quenching
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引言
由于量子点优异的荧光性质，基于量子点的荧光分析法的应用已经十分广泛，而量子点的磷光性质及其在分析检测中的应用得到的关注仍然较少。相对于荧光分析法，室温磷光法(Room-temperaturephosphorescence，RTP）具有很多的优点：磷光相对于荧光是一种更为少见的现象，因此进行检测时的选择性得到进一步的增强！；磷
*通讯联系人，Email;wjin@bnu.edu.cn 万方数据
光寿命比荧光长，因此在进行磷光检测时可以避免自体荧光和散射光的干扰，且对仪器的要求低，磷光寿命的测量比荧光寿命测量更简便12)]。现如今，RTP方法已广泛用于药物分析、环境中杀虫剂和多环芳烃的检测，以及手性识别等(3~7)，但利用量子点磷光对于重金属离子的RTP检测还报道较少。
具有磷光性质的量子点较少，常见于掺杂型的量子点。掺杂型量子点指的是在单纯的量子点