当前位置：
X-MOL 学术
›
J. Phys. Chem. C
›
论文详情
Our official English website, www.x-mol.net, welcomes your
feedback! (Note: you will need to create a separate account there.)
Thermal Conductivity and Pressure-Dependent Raman Studies of Vertical Graphene Nanosheets
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2016-10-20 00:00:00 , DOI: 10.1021/acs.jpcc.6b08754 K. K. Mishra 1 , Subrata Ghosh 1 , T. R. Ravindran 1 , S. Amirthapandian 1 , M. Kamruddin 1
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2016-10-20 00:00:00 , DOI: 10.1021/acs.jpcc.6b08754 K. K. Mishra 1 , Subrata Ghosh 1 , T. R. Ravindran 1 , S. Amirthapandian 1 , M. Kamruddin 1
Affiliation
|
Thermal and mechanical properties of graphene sheet are of significant importance in the areas of thermal and stress management, respectively. Here, we report the thermal conductivity and high-pressure behaviors of unsupported vertical graphene nanosheets (VGNs) grown by electron cyclotron resonance-plasma enhanced chemical vapor deposition method. Structural morphology of the as-grown VGNs on SiO2/Si substrate suggests a homogeneous, uniformly interconnected network of graphene sheets standing vertically on a basal nanographitic layer. On examination of edges of exfoliated sheets using transmission electron microscopy, seven layers of graphene is estimated. The frequency of the G-band (E2g-in plane mode) is found to vary linearly with temperature. The first-order temperature coefficient for G-band is found to be 1.47(1) × 10–2 cm–1 K–1. Using the G-band temperature coefficient and its position dependence on excitation laser power, the thermal conductivity of the VGNs at room temperature is estimated to be 250 (19) W m–1 K–1. The effect of pressure (P) on the G-mode frequency (ω) of unsupported VGNs is investigated by in situ Raman spectroscopic studies up to 40 GPa using a diamond anvil cell. Above 16 GPa, discontinuity in the ω versus P curve suggests a disruption of long-range order in the graphene layers resulting in a deviation from two-dimensional layer structure. Persistence of local sp2-hybridization up to 40 GPa is evident from the presence of G-band at this highest pressure. Upon decompression, VGN is found to recover its original ordered structure.
中文翻译：
垂直石墨烯纳米片的热导率和压力依赖性拉曼研究
石墨烯片的热性能和机械性能分别在热管理和应力管理领域具有重要意义。在这里，我们报告通过电子回旋共振等离子体增强化学气相沉积法生长的无支撑垂直石墨烯纳米片（VGNs）的热导率和高压行为。SiO 2 / Si基板上已生长的VGN的结构形态表明，石墨烯片的均匀，均匀互连的网络垂直竖立在基础纳米石墨层上。在使用透射电子显微镜检查剥离薄片的边缘时，估计了七层石墨烯。G频段的频率（E 2g-在平面模式下）被发现随温度线性变化。发现G波段的一阶温度系数为1.47（1）×10 –2 cm –1 K –1。利用G波段温度系数及其对激发激光功率的位置依赖性，室温下VGN的热导率估计为250（19）W m –1 K –1。压力（P）对无支撑VGN的G模频率（ω）的影响是通过使用金刚石砧盒的拉曼光谱原位研究（最高40 GPa）进行研究的。高于16 GPa，ω相对于P的不连续性曲线表明石墨烯层中的长程有序破坏，导致与二维层结构的偏离。通过在该最高压力下存在G-带，可以证明高达40 GPa的局部sp 2-杂交的持久性。减压后，发现VGN恢复其原始有序结构。
更新日期：2016-10-20
中文翻译：
垂直石墨烯纳米片的热导率和压力依赖性拉曼研究
石墨烯片的热性能和机械性能分别在热管理和应力管理领域具有重要意义。在这里，我们报告通过电子回旋共振等离子体增强化学气相沉积法生长的无支撑垂直石墨烯纳米片（VGNs）的热导率和高压行为。SiO 2 / Si基板上已生长的VGN的结构形态表明，石墨烯片的均匀，均匀互连的网络垂直竖立在基础纳米石墨层上。在使用透射电子显微镜检查剥离薄片的边缘时，估计了七层石墨烯。G频段的频率（E 2g-在平面模式下）被发现随温度线性变化。发现G波段的一阶温度系数为1.47（1）×10 –2 cm –1 K –1。利用G波段温度系数及其对激发激光功率的位置依赖性，室温下VGN的热导率估计为250（19）W m –1 K –1。压力（P）对无支撑VGN的G模频率（ω）的影响是通过使用金刚石砧盒的拉曼光谱原位研究（最高40 GPa）进行研究的。高于16 GPa，ω相对于P的不连续性曲线表明石墨烯层中的长程有序破坏，导致与二维层结构的偏离。通过在该最高压力下存在G-带，可以证明高达40 GPa的局部sp 2-杂交的持久性。减压后，发现VGN恢复其原始有序结构。
京公网安备 11010802027423号