Ben Dong,Baoyan Li,Yi Cao,Xinlei Meng,Han Yan,Shusheng Ge,Yun Lu
Two series of thiophene oligomers and terthiophene oligomers consisting of both thiophene and indole moieties have been synthesized. They have same excitation-dependent photoluminescence characteristics, but different bandgaps and absorption behaviors, which relates to the number and denseness of indoles in the conjugated oligomers and the length of alkyl chains on indole moiety due to varied the π-π stacking interaction of conjugated structures in the as-prepared oligomers. A simple electrochromic device based on such a conjugated oligomer displays a novel four-color electrochromism from red to yellow, green and puce with the increased potential and possesses good environmental and redox stability. Such conjugated oligomer also exhibits high sensitivity and selectivity for Zn 2+ detection.
Quan Song,Yunsu Ma,Xu Wang,Tang Tang,Yueyue Song,Yujie Ma,Guanhong Xu,Fangdi Wei,Yao Cen,Qin Hu
In this work, a novel strategy for Zn 2+ detection was established by using an “on-off-on” ratiometric fluorescent nanosensor with the help of ethylene diaminetetraacetic acid (EDTA), a common metal chelating agent. The simple and practical ratiometric fluorescent nanosensor was synthesized by covalently binding CdTe quantum dots (QDs) and carbon dots (CDs), possessing two emission peaks at 525 nm and 450 nm under a single wavelength excitation of 360 nm, respectively. The CdTe QDs served as the response signal label, and the CDs, having no response to the analytes, acted as the reference signal. The fluorescence emission of the nanosensor was turned off to create a low-level “off” state when EDTA was added, and turned on dramatically with the addition of the target Zn 2+ . Under the optimal conditions, the change of the fluorescence intensity ratio of the nanosensor at 525 nm and 450 nm (ΔF 525 /F 450 ) had good linearity against the concentrations of Zn 2+ within a dynamic linear range of 0.50–40 μM. The limit of detection was as low as 0.33 μM (3σ/K), which was low enough for the detection of Zn 2+ in human body. The proposed method was successfully applied to the detection of Zn 2+ in human urine and plasma with RSDs less than 10%. The results show that the as-prepared QDs-CDs ratiometric nanosensor has potential application of clinical detection of Zn 2+ in the human body.
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