Pengtao Sheng,Youyang Xie,Shuyu Han,Yanling Li,Weili Li
Manganese ion-doped quantum dots (QDs) with wide band gaps have been widely investigated to modify their electronic, magnetic, and photophysical properties. The research on Mn-doped Cu-In-Se QDs with narrow band gaps has been minimal due to the profound differences in the reaction reactivity of cations. In this work, photoluminescent and magnetic Cu-In-Se QD nanoprobes were designed and synthesized by introducing Zn 2+ ions, which function as an intermediate acid that can regulate metal ion acidity to enhance the doping efficiency of Mn 2+ ions in a facile phosphine-free hot-injection protocol. The emission peaks of Zn-doped Cu-In-Se QDs and MnZn-doped Cu-In-Se QDs exhibit significant composition-dependent shifts. Moreover, incorporating manganese ions confers a paramagnetic character to MnZn-doped Cu-In-Se QDs and provides a quasi-core shell structure with an Mn-rich alloy shell layer, as demonstrated by the micro-structural surface analysis and electron paramagnetic resonance spectroscopy . Analyzing the decay lifetime and quantum yield reveals that this host-dopant coupling involves a preferential energy transfer from the host material to the dopant (Mn 2+ ions), wherein photogenerated electrons nonradiatively transfer to the 4 T 1 level of Mn dopant and then recombine with the Cu x state above the valance band of host QDs. The ability to serve as nanoprobes for the visualization of tumors through fluorescence and magnetic resonance dual-modality imaging makes these ternary MnZn-doped Cu-In-Se QDs strong candidates for practical applications in biology/biomedicine field.
Peiyuan Ji,Jing Wan,Junlin Lu,Dazhi Zhang,Chenguo Hu,Yi Xi
The development of simple preparation and excellent capacity performance electrode materials is the key to energy conversion and storage for supercapacitors. Based on the growth mechanism of crystal, Zn induced NiCo nanosheets and nanoneedles composite structure deposed on Ni foam (ZNC) are successfully attained by a facile one-step method, the growth mechanism of the composite structure is further discussed. Because of its unique composites structure and additional modification of carbon, the carbon modified ZNC (ZNC@C) delivers better energy storage ability (2280 mC cm−2 at 2 mA cm−2) compare to ZNC. An asymmetric supercapacitor (ASC) is assembled by ZNC@C as the positive electrode and carbonized popcorn as the negative electrode. The ASC exhibits good energy storage performance. Zn also positively affects the adsorption energy to enhance the capacitance property based on Density Functional theory calculation. The simple method for the composite structure by tuning the kinetics behaver of the crystal can provide a new strategy in synthesizing the materials, and the material with a unique structure and high performance will have potential applications in the field of energy storage.
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