Recently, shu-hong yu, a professor at the university of science and technology of China group and zhen-yu li team cooperation, in the form of sulfide semiconductor design synthesis and photovoltaic applications have made new progress. Research results to cover papers published on September 26, in the journal of the American chemical society "(j. Am. Chem. Soc., 2016138 (39), 12913-12919), and was JACS Spotlights selected as the research highlights.
Novel synthesis of nanocrystalline materials and their formation mechanism is the focus in research on synthesis of nanocrystalline colloid wet chemical methods. Copper sulfide (Cu2 - xS) is a kind of traditional semiconductor materials, as the change of x presents different crystal structure, when the x value increases, the forbidden band width is reduced, the surface plasma resonance enhanced, thus by semiconductor properties change to gold. People for the single components and the different phase of Cu2 - xS research has done a lot of work. At present the synthesis of nano heterojunction attention, because it can integrate the advantages of different material components and is better than that of a single component of synergies. In contrast, studies of polymorph nano heterojunction is relatively less, if can of semiconductor Cu2 - xS and metallicity CuS compound together, is expected to make the show more peculiar properties.
In order to achieve this goal, the researchers developed the colloid chemical precursors induced "wet method were prepared for the first time more than one kind of unique form heterojunction Cu1.94 S - CuS, namely, the one-dimensional semiconductor Cu1.94 S and two-dimensional metallicity CuS compound together, to form a special" interaction "interface. In the process of synthesis, precursors Mn (S2CNEt2) 2 play a crucial role, it can induce and control Cu1.94 S to CuS phase transition process, the formation of the copper sulfide polymorph Cu1.94 S - CuS stable nano heterojunction can exist. This unique Cu1.94 S - CuS nano heterojunction which can effectively absorb sunlight the visible and near infrared region. With density functional theory calculations show that the special interface can build similar to the "metal - semiconductor interface structure, so as to build a similar to the type - II heterostructure, effectively promote the system of the separation of electrons and holes, the photovoltaic performance of the system of material significantly increased.
This is based on the precursors induced the synthesis methods of sulfide heterogeneous nanostructures, helps people to precisely control the structure of nano-materials and deep understanding of its formation mechanism. At the same time, this kind of precious metals in heterogeneous nanostructures of synthetic strategy, to improve and optimize the traditional semiconductor photoelectric conversion performance provides new train of thought.
Previously, shu-hong yu group also found that the organic phosphonic and Ag + and Bi3 + coordination complexation and reduction at high temperature for the phenomenon of elemental silver and bismuth elemental, thus developed a based on organic phosphonic under the action of silver and bismuth based nanocrystalline and heterogeneous nanostructures general synthetic methods, the successful synthesis of Ag, Bi, Ag - Ni3S2, Ag - ZnS, the Ag - AgInS2 administered, Ag - Bi and Bi - Cu7S4 and a series of silver and bismuth nanomaterials, which for the synthesis of colloidal nanocrystals is a powerful supplement. Researchers found that silver and bismuth chalcogenide is dissolved in organic amine balance, according to Louis, hard and soft acid-base theory can solution of organic phosphine and Ag + and Bi3 + coordination complexation, break its dissolving balance, release more Ag + and Bi3 +, which at high temperatures is organic amine reduction into the elemental silver and bismuth. Through the method of synthesis of nanocrystalline and heterojunction in catalysis, photoelectric conversion, biological sensors has a potential application value. Related research findings are published in the journal of the American chemical society journal on (J.A m.C hem. Soc., 2015137 (16), 5390-5396).
The above research work by the national natural science foundation research group, national natural science foundation of key innovation fund, the national important scientific research plan, frontier science key research project of Chinese academy of sciences, suzhou nanotechnology collaborative innovation center, nano scientific excellence innovation center of Chinese academy of sciences, hefei big science center of excellence user fund support.
