Department of Physics, Faculty of Science, Arak University, Arak 3815688394, Iran. Institute of Nanoscience and Nanotechnology, Arak University, Arak, Iran. Department of Chemistry, Faculty of Science, Ilam University, 65315-516, Ilam, Iran.
Nanotechnology. 2018 Nov 2;29(44):445602. doi: 10.1088/1361-6528/aada29. Epub 2018 Aug 14.
In this paper, an aqueous-based approach is introduced for facile, fast, and green synthesis of gradient-alloyed Fe-doped ZnSe(S)@ZnSe(S) core:shell quantum dots (QDs) with intense and stable emission. Co-utilization of co-nucleation and growth doping strategies, along with systematic optimization of emission intensity, provide a well-controllable/general method to achieve internally doped QDs (d-dots) with intense emission. Results indicate that the alloyed ZnSe(S)@ZnSe(S) core:shell QDs have a gradient structure that consists of a Se-rich core and a S-rich shell. This gradient structure cannot only passivate the core d-dots by means of the wider band gap S-rich shell, but also minimizes the lattice mismatch between alloyed core-shell structures. Using this novel strategy and utilizing the wider band gap S-rich shell can obviously increase the cyan emission intensity and also drastically improve the emission stability against chemical and optical corrosion. Furthermore, the cytotoxicity experiments indicate that the obtained d-dots are nontoxic nanomaterials, and thus they can be considered as a promising alternative to conventional Cd-based QDs for fluorescent probes in biological fields. Finally, it is demonstrated that the present low-toxicity and gradient-alloyed core:shell d-dots can be used as sensitive chemical detectors for Pb ions with excellent selectivity, small detection limit, and rapid response time.
本文提出了一种水相法，用于简便、快速、绿色合成具有强而稳定发射的梯度合金 Fe 掺杂 ZnSe(S)@ZnSe(S)核壳量子点(QD)。共成核和生长掺杂策略的共同利用，以及发射强度的系统优化，为实现具有强发射的内掺杂 QD(d-dot)提供了一种可控/通用的方法。结果表明，合金化的 ZnSe(S)@ZnSe(S)核壳 QD 具有由富 Se 核和富 S 壳组成的梯度结构。这种梯度结构不仅可以通过较宽的带隙富 S 壳来钝化核 d-dot，而且还可以最小化合金核壳结构之间的晶格失配。利用这种新策略和利用较宽的带隙富 S 壳，可以明显提高蓝绿发射强度，并显著提高对化学和光学腐蚀的发射稳定性。此外，细胞毒性实验表明，所获得的 d-dot 是无毒的纳米材料，因此它们可以作为生物领域中传统 Cd 基 QD 荧光探针的有前途的替代品。最后，证明了本研究中的低毒性和梯度合金核壳 d-dot 可以用作对 Pb 离子具有优异选择性、小检测限和快速响应时间的灵敏化学探测器。
