A novel bipolar conjugated polymer containing triphenylamine and 1, 3, 4-oxadiazole units was synthesized by Suzuki reaction. Its structure and properties were characterized by NMR, IR, UV-Vis, PL spectroscopy and el...A novel bipolar conjugated polymer containing triphenylamine and 1, 3, 4-oxadiazole units was synthesized by Suzuki reaction. Its structure and properties were characterized by NMR, IR, UV-Vis, PL spectroscopy and electrochemical measurement. The photoluminescent spectroscopy and cyclic voltammograms measurement demonstrated that the resulting polymer shows blue emission (477 nm) and possesses both electron and hole-transporting property.展开更多
Topological insulators （TIs） are a new state of quantum matter with a band gap in bulk and conducting surface states. In this work, the Raman spectra of topological insulator Bi2Te3 films prepared by molecular beam ...Topological insulators （TIs） are a new state of quantum matter with a band gap in bulk and conducting surface states. In this work, the Raman spectra of topological insulator Bi2Te3 films prepared by molecular beam epitaxy （MBE） have been measured by an in situ ultrahigh vacuum （UHV）-MBE-Raman spectroscopy system. When the thickness of Bi2Te3 films decreases from 40 quintuple-layers （QL） to 1 QL, the spectral characteristics of some Raman modes appearing in bulk Bi2Te3 vary and a new vibrational mode appears, which has not been reported in previous studies and might be related to quantum size effects and symmetry breaking. In addition, an obvious change was observed at 3 QL when a Dirac cone formed. These results offer some new information about the novel quantum states of TIs.展开更多
基金This work was supported by the National Natural Science Foundation of China (No. 29725410 and 29992530) and Chinese Academy of Sciences (KJ951-A1-501-01).
文摘A novel bipolar conjugated polymer containing triphenylamine and 1, 3, 4-oxadiazole units was synthesized by Suzuki reaction. Its structure and properties were characterized by NMR, IR, UV-Vis, PL spectroscopy and electrochemical measurement. The photoluminescent spectroscopy and cyclic voltammograms measurement demonstrated that the resulting polymer shows blue emission (477 nm) and possesses both electron and hole-transporting property.
文摘Topological insulators （TIs） are a new state of quantum matter with a band gap in bulk and conducting surface states. In this work, the Raman spectra of topological insulator Bi2Te3 films prepared by molecular beam epitaxy （MBE） have been measured by an in situ ultrahigh vacuum （UHV）-MBE-Raman spectroscopy system. When the thickness of Bi2Te3 films decreases from 40 quintuple-layers （QL） to 1 QL, the spectral characteristics of some Raman modes appearing in bulk Bi2Te3 vary and a new vibrational mode appears, which has not been reported in previous studies and might be related to quantum size effects and symmetry breaking. In addition, an obvious change was observed at 3 QL when a Dirac cone formed. These results offer some new information about the novel quantum states of TIs.
