Synthesis Of ZnS: Mn Quantum Dots And Room Temperature Phosphorescence Detection

Quantum dot is a kind of light-emitting semiconducting particle and its radius size isbetween1and100nanometers. It has distinctive photology and size-dependent character,wide and continuous absorption spectra, symmetry shape emission spectrum and narrow halfpeak width. Also the optical stability of quantum dot is well. Furthermore we can obtaindifferent fluorescence colours by adjusting its size. For quantum dots, all of these propertiesbring them extensive research and application in chemical, biology, physics, material andother fields.In recent years, doped quantum dots, especially the ones that have no heavy metal ions,have become the focus of luminescence materials. Compared with the quantum dots whichhave no heavy metal ions, doped quantum dots have low toxicity, the capacity of overcomingself-absorption and insensitivity of heat, chemical and photochemical, however, they stillhave inherent optical properties. Fluorescent properties of the quantum dot has been widelyapplied in many fields so far, nevertheless, we have not paid attention to the property ofroom-temperature phosphorescence.In this paper, the main research contents are summarized as follows:(1) Mn-doped ZnSquantum dots were synthesized using mercapto propionic acid as stabilizer in the water phase.The experiment device that was used was simple. The reaction conditions were mild and easyto control. And its using reagents were common and low toxic. What’s more, it had a low costof preparation. Finally, the synthesized results were characterized with PL, UV and XRD. Itturned out that the fluorescence of Mn-doped ZnS quantum dot was excellent and its size wasuniform. The product was cubic crystal.(2) Based on the room-temperature phosphorescenceproperties of Mn-doped ZnS quantum dot, a simple, rapid, high sensitivity and low detectionlimit method of detecting Hg2+in the solution was established. The linear range of thedetection of Hg2+is10-5-10-3mol·L-1and the detection limit is9.7×10-6mol·L-1. This methodnot only can exclude the interference of fluorescence and scattered light effectively, but alsothe revulsant and deoxidizer were not demonded.(3) The room room-temperaturephosphorescence properties of Mn-doped ZnS quantum dot was explored to develop a newmethod for detection of NH+4in water phase based on the relation between Mn-doped ZnSquantum dot and NH+4. We also studied the influence of different pH and quantum dots’ concentration to detect NH+4. And it is concluded that the mechanism between NH+4andmercapto propionic acid-capped Mn-doped ZnS quantum dots met lundgren muir adsorptionisotherm.