Sodium Rare-Earth Fluoride Nanocrystals NaRF₄(R=Nd, Eu) And CNTs/NaEuF₄ Heterostructures: Synthesis And Optical And Electrical Properties

At present, these Carbon nanotube-Nanocrystal Heterostrostrutures show eminent prospects and opportunities for new applications in a wide variety of areas. The superiority of this system lies in the fact that the combination of the properties of two functional nanoscale materials can be used to achieve a wider range of application. Compared to these semiconductor Nanocrysrals, the Rare-earth compounds have low toxicity, sharp emission spectrum of fluorescence, high quantum efficiencies, a large Stokes shift and longer wavelength in the emission of rare-earth compounds merits and so on, the CNT/rare-earth-based heterostructures would show more excellent luminescent, ferromagnetic and electric properties and so possess a wider range of application.Here we have fabricated cubic phase and hexagonal NaREF4 (RE=Eu, Nd) NCs via theco-thermolysis of Na(CF3COO)and R(CF3COO)3 inoleic acid/oleylamine/ octadecene. The cubic phase NaEuF4 NCs can be synthesized through charging temperature ( 260℃～300℃) and times. The hexagonal NaEuF4 nanorods was prepared by increasing reaction temperature ( 330℃) and changing the moler ratio of reaction materials in a similar way. The Cubic phase NaEuF4 NCs and hexagonal NaEuF4 nanorods demonstrated similar PL property, showed the luminescence property of Eu3+ ions- sharp emission spectrum of fluorescence showed line emissions and excellent emissions intensity. But cubic phase NaEuF4 NCs had more excellent fluorescence property comparing with hexagonal NaEuF4 nanorods. Meanwhile in the similar way, we also successfully fabricated cubic phase and hexagonal NaNdF4 NCs.The CNT was functionlized without destroying the structure of the CNT by modified with PAH. And the cubic NaEuF4 NCs with excellent luminescence was conpled to the functionalied CNTs, and formed CNT/NaEuF4 Heterostructures. The luminescence and electric transport property of the CNT/NCs was investigated through PL and photo-assisted conductive AFM (PC-AFM) measurements. The results showed that energy transfer occurred in cubic NaEuF4 NCs and functionalization CNTs and the excitated electrons of cubic NaEuF4 NCs transferred to the CNT and the PL quenching occurred without PL emissions. For CNT/NC heterostructures's applying in electronic devices, we studied electric transport of the heterostructures through PC-AFM and found that the composites under UV illumination had a good photo-electric switching effect and grouped to study the occurence mechanism.