The use of single-layer MoS2 in light emitting devices requires innovative methods to enhance its low photoluminescence （PL） quantum yield. In this work, we report that single-layer MoS2 with a strong PL can be prep...The use of single-layer MoS2 in light emitting devices requires innovative methods to enhance its low photoluminescence （PL） quantum yield. In this work, we report that single-layer MoS2 with a strong PL can be prepared by oxidizing bilayer MoS2 using W-ozone oxidation. We show that as compared to mechanically-exfoliated single-layer MoS2, the PL intensity of the single-layer MoS2 prepared by W-ozone oxidation is enhanced by 20-30 times. We demonstrate that the PL intensity of both neutral excitons and trions （charged excitons） can be greatly enhanced in the oxidized MoS2 samples. These results provide novel insights into the PL enhancement of single-layer MoS2.展开更多
The metal-organic framework Zn4O[1,4-benzenedicarboxylate]3(Zn4O[CO2-C6H4-CO2]3,commonly known as MOF-5,was prepared by the ultrasonic irradiation method.The catalyst was characterized by X-ray diffraction(XRD) and Fo...The metal-organic framework Zn4O[1,4-benzenedicarboxylate]3(Zn4O[CO2-C6H4-CO2]3,commonly known as MOF-5,was prepared by the ultrasonic irradiation method.The catalyst was characterized by X-ray diffraction(XRD) and Fourier transform infrared(FTIR) spectroscopy.It was then used as the catalyst for the preparation of polycarbonate diol(PCDL) via the transesterification between diphenyl carbonate(DPC) and 1,6-hexandiol(1,6-HD).Its catalytic activity in the transesterification process is evaluated by the yield of phenol,and its catalytic activity in the polycondensation process is determined by the number-average molecular weight(Mn) and the hydroxyl value.Compared to the triethylenediamine(C6H12N2),Mg-Al layered double hydroxide(Mg-Al LDH),sodium ethoxide(C2H5ONa) and sodium methoxide(CH3ONa),MOF-5 exhibits highest catalytic activity for the preparation of PCDL.Under reaction conditions(n(1,6-HD)/n(DPC) = 1.2,w(catalyst) = 0.03%,198 ℃),the yield of phenol is up to 90.1% and the PCDL shows highest Mn and lowest hydroxyl value.展开更多
文摘The use of single-layer MoS2 in light emitting devices requires innovative methods to enhance its low photoluminescence （PL） quantum yield. In this work, we report that single-layer MoS2 with a strong PL can be prepared by oxidizing bilayer MoS2 using W-ozone oxidation. We show that as compared to mechanically-exfoliated single-layer MoS2, the PL intensity of the single-layer MoS2 prepared by W-ozone oxidation is enhanced by 20-30 times. We demonstrate that the PL intensity of both neutral excitons and trions （charged excitons） can be greatly enhanced in the oxidized MoS2 samples. These results provide novel insights into the PL enhancement of single-layer MoS2.
基金supported by the Key Projects in the National Science & Technology Pillar Program during the Eleventh Five-Year Plan Period (2006BAE02B03)Jiangsu Provincial Science & Technology Pillar Program (BE2010065)
文摘The metal-organic framework Zn4O[1,4-benzenedicarboxylate]3(Zn4O[CO2-C6H4-CO2]3,commonly known as MOF-5,was prepared by the ultrasonic irradiation method.The catalyst was characterized by X-ray diffraction(XRD) and Fourier transform infrared(FTIR) spectroscopy.It was then used as the catalyst for the preparation of polycarbonate diol(PCDL) via the transesterification between diphenyl carbonate(DPC) and 1,6-hexandiol(1,6-HD).Its catalytic activity in the transesterification process is evaluated by the yield of phenol,and its catalytic activity in the polycondensation process is determined by the number-average molecular weight(Mn) and the hydroxyl value.Compared to the triethylenediamine(C6H12N2),Mg-Al layered double hydroxide(Mg-Al LDH),sodium ethoxide(C2H5ONa) and sodium methoxide(CH3ONa),MOF-5 exhibits highest catalytic activity for the preparation of PCDL.Under reaction conditions(n(1,6-HD)/n(DPC) = 1.2,w(catalyst) = 0.03%,198 ℃),the yield of phenol is up to 90.1% and the PCDL shows highest Mn and lowest hydroxyl value.
