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BIT Publishes New Findings on Nature Nanotechnology

release date :2018-01-04 12:00:00  |   [ close window ]ViewCount:

  Translator: News Agency of BIT Li Siyu

  Editor: News Agency of BIT Zhao Jie




  On December 18, 2017, the latest research result Excitonic Pathway to Photoinduced Magnetism in Colloidal Nanocrystals with Nonmagnetic Dopants found by professor Zhang Jiatao of Beijing Institute of Technology (BIT) and professor Sergio Brovelli of Milan Bicocca University, was published on Nature Nanotechnology , the international authoritative journal about nanotechnology.

  Due to its adjustable characteristic and solution processibility, colloidal semiconductor nanocrystal has got more and more attention in the field of photoelectron and photonics. By adding impurity into conductor nanocrystal to change its electrical property can effectively adjust the property of light, electricity and magnetism of semiconductor nanocrystal, making it available to solid-state lighting, laser, photovoltaic device, biomarker and fluorescence accumulator. Transition metal ions mixed with semiconductor nanocrystal and the electron configuration interacted with sp-d of the d-electron can achieve the displacement of the fluorescence of nanocrystal Stokes and high electrical transmission performance as well as the controllable magnetism.

  As a new doping element, Ag+ is usually used in III-V and II-VI semiconductor nanomaterial. Doped Ag+ causes the optical coupling of the main conduction band. Because of its completely filled 4d orbital, Ag+ is non-magnetic. The fluorescence is attributed to hole-transfer caused by light to Ag+ and recombination with conducting electrons. However, the principle of this photoactivation process and the electronic configuration of Ag+ remains unclear, so that the research group of BIT professor Zhang cooperate with the Italian team led by professor Brovelli to systematically study on the excitation and decay process of CdSe nanocrystal doped with Ag. They found it interesting that photogenerated hole made Ag+ change to paramagnetic Ag2+. The compound process of excitons is closely related to photoinduced magnetism. They observed intense photoactivation magnetism and diluted magnetic behavior of semiconductor nanomaterial, which shows that magnetic semiconductor nanomaterial optically converted can be obtained by excitation process induced by nonmagnetic dopants, realizing the effective control of its property of light, electricity and magnetism together with its application to photoelectric self-spinning devices!

  Professor Zhang Jiatao and School of Materials Science and Engineering are the joint corresponding author and the second corresponding entity respectively. The main job on experiment was done by the PhD candidate Valerio Pinchetti in Milan Bicocca University together with the PhD candidate Di Qiumei in School of Materials Science and Engineering in BIT. Besides, professor Scott A. Crooker in Los Alamos National Laboratory conducted the test on magneto-optical property. The achievement is benefited by the financial support of the Plan 111 in BIT, which is a model for school to promote the globalization of building first-class discipline on “new materials science and technology”. The research also got support by project 51372025, major integration project 91323301, and major project 51631001 of State Natural Science Foundation. Great thanks to all of them.





  Link: Nature Nanotechnology 2017, doi:10.1038/s41565-017-0024-8 .

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