In this paper, we investigate the length dependence of linear and nonlinear optical properties of finite-length BN nanotubes. The recently predicted smallest BN（5,0） nanotube with configuration stabilization is sele...In this paper, we investigate the length dependence of linear and nonlinear optical properties of finite-length BN nanotubes. The recently predicted smallest BN（5,0） nanotube with configuration stabilization is selected as an example. The energy gap and optical gap show the obvious length dependence with the increase of nanotube length. When the length reaches about 24 /~, the energy gap will saturate at about 3.2 eV, which agrees well with the corrected quasi- particle energy gap. The third-order polarizabilities increase with the increase of tube length. Two-photon allowed excited states have significant contributions to the third-order polarizabilities of BN（5,0） nanotube.展开更多
Novel manganese and boron containing nanomaterials have been investigated for applications in rechargeable lithium ion batteries （L1Bs） in recent years owing since they are more environmentally-benign and more abund...Novel manganese and boron containing nanomaterials have been investigated for applications in rechargeable lithium ion batteries （L1Bs） in recent years owing since they are more environmentally-benign and more abundant in nature than the materials currently employed. In this study, one-dimensional （1D） Mn3B7O13OH nanorods and MnBO2OH nanorod bundles were controllably fabricated by using NH4HB4O7 and Mn（NO3）2 as reagents via a hydrothermal or solvothermal process, respectively, without any surfactants or templates at 220 ℃. It is interesting to find that both materials are transformed into Mn2OBO3 nanorods/nanorod bundles by subsequent calcination. The formation processes of the above 1D borate containing products were investigated and the as-obtained four kinds of borates were studied as novel anode materials. It was found that the Mn2OBO3 nanorods displayed the best performance among the four borates, delivering an initial discharge capacitiy of 1,172 mAh·g^-1 at 100 mA·g^-1, and 724 mAh.g could be retained after 120 cycles. A full battery composed of a Mn2OBO3 nanorod anode and a commercial LiFePO4 （or LiCoO2） cathode has also been assembled for the first time, which delivered an initial discharge capacity of 949 mAh·g^-1 （779 mAh·g^-1 for LiCoO2）. The excellent cycle and rate performances of the products reveal their potential applications as anodes for LIBs.展开更多
基金Project supported by the National Natural Science Foundation of China （Grant Nos 20373073 and 90201015）, the Science Foundation of Fujian Province, China （Grant Nos E0210028 and 2002F010）, and the Foundation of State Key Laboratory of Structural Chemistry, China （Grant No 030060）.
文摘In this paper, we investigate the length dependence of linear and nonlinear optical properties of finite-length BN nanotubes. The recently predicted smallest BN（5,0） nanotube with configuration stabilization is selected as an example. The energy gap and optical gap show the obvious length dependence with the increase of nanotube length. When the length reaches about 24 /~, the energy gap will saturate at about 3.2 eV, which agrees well with the corrected quasi- particle energy gap. The third-order polarizabilities increase with the increase of tube length. Two-photon allowed excited states have significant contributions to the third-order polarizabilities of BN（5,0） nanotube.
文摘Novel manganese and boron containing nanomaterials have been investigated for applications in rechargeable lithium ion batteries （L1Bs） in recent years owing since they are more environmentally-benign and more abundant in nature than the materials currently employed. In this study, one-dimensional （1D） Mn3B7O13OH nanorods and MnBO2OH nanorod bundles were controllably fabricated by using NH4HB4O7 and Mn（NO3）2 as reagents via a hydrothermal or solvothermal process, respectively, without any surfactants or templates at 220 ℃. It is interesting to find that both materials are transformed into Mn2OBO3 nanorods/nanorod bundles by subsequent calcination. The formation processes of the above 1D borate containing products were investigated and the as-obtained four kinds of borates were studied as novel anode materials. It was found that the Mn2OBO3 nanorods displayed the best performance among the four borates, delivering an initial discharge capacitiy of 1,172 mAh·g^-1 at 100 mA·g^-1, and 724 mAh.g could be retained after 120 cycles. A full battery composed of a Mn2OBO3 nanorod anode and a commercial LiFePO4 （or LiCoO2） cathode has also been assembled for the first time, which delivered an initial discharge capacity of 949 mAh·g^-1 （779 mAh·g^-1 for LiCoO2）. The excellent cycle and rate performances of the products reveal their potential applications as anodes for LIBs.
