Recently, Professor Yu Shuhong from University of Science and Technology of China and Li Zhenyu research group collaborated to make new progress in the design and synthesis of multiform sulfide semiconductors and the application of photoelectric conversion. The research was published in a cover paper on September 26, J. Am. Chem. Soc. 2016, 138 (39), and was selected as a research highlight by JACS Spotlights.
The synthesis and formation mechanism of novel nanocrystalline materials is the focus of the current research on the synthesis of nanocrystals by the colloid wet chemical method. Copper sulfide (Cu2-xS) is a kind of traditional semiconductor materials, showing different crystal structures with the change of x value. When the value of x increases, the band gap decreases and the surface plasmon resonance effect increases. Sexual to metallic transformation. Much work has been done on the research of Cu2-xS with single component and different phases. The current synthesis of nano-heterojunctions has drawn much attention because of its ability to integrate the advantages of different material components to achieve synergistic effects over single components. In contrast, there are relatively few studies on polymorphic nano-heterojunctions, and it is expected to render them more exotic if they can be combined with semiconducting Cu2-xS and metallic CuS.
In order to achieve this goal, researchers developed the first wet colloidal "precursor-induced" method successfully prepared a unique polymorphic heterojunctions Cu1.94S-CuS, that is, one-dimensional semiconductor Cu1.94S and two-dimensional Metallic CuS compound together to form a special "self-interaction" interface. The precursor Mn (S2CNEt2) 2 plays a crucial role in the synthesis process. It can induce and control the phase transition of Cu1.94S to CuS, and make the formed Cu1.94S-CuS polymorph of Cu1.44S-CuS The knot can be stable. This unique Cu1.94S-CuS nano-heterojunction effectively absorbs the visible and near-infrared regions of sunlight. The results of density functional theory show that this special interface can be constructed similar to the "metal-semiconductor" interface structure to construct a type-II heterostructure similar to that of the system, which effectively promotes the separation of electrons and holes in the system. With the system to enhance the photoelectric conversion properties of materials.
This method based on precursor-induced synthesis of sulfide hetero-nanostructures helps to precisely control the structure of nanomaterials and to understand their formation mechanism. At the same time, the synthesis strategy of heterogeneous nanostructures without precious metals will provide new ideas for improving and optimizing the photoelectric conversion performance of traditional semiconductors.
Previously, Yu Shuhong research group also found that organic phosphine and Ag + and Bi3 coordination complexing and then under high temperature was reduced to silver elemental and bismuth single substance phenomenon, thus developing a based on the effect of organic phosphine and bismuth base A series of silver and bismuth based nanomaterials such as Ag, Bi, Ag-Ni3S2, Ag-ZnS, Ag-AgInS2, Ag-Bi and Bi-Cu7S4 have been synthesized successfully by the common synthesis method of nanocrystal and its heterogeneous nanostructures. This is a powerful addition to the synthesis of colloidal nanocrystals. The researchers found that silver and bismuth chalcogen compounds exist in the balance of organic amine dissolution, according to Lewis soft and hard acid-base theory, the solution of organic phosphine can be complexed with Ag + and Bi3 +, to break the balance of its dissolution and release more Ag + and Bi3 +, and then reduced to organic elements at high temperature silver and bismuth elemental. The nanocrystals and heterojunctions synthesized by this method have potential applications in the fields of catalysis, photoelectric conversion, biosensing and the like. Relevant findings are published in the Journal of the American Chemical Society (J.Am.Chem.Soc. 2015, 137 (16), 5390-5396).
The above research work was supported by the Innovative Research Group of NSFC, the National Natural Science Foundation of China, the National Major Scientific Research Program, the CAS Key Research Projects, the Suzhou Nano Science and Technology Collaborative Innovation Center, the CAS Nano Scientific Excellence Innovation Center, the Hefei University Science Center for Excellence User Funding.
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