光刺激石墨烯极长的非辐射放松被氧化极大地加速:时间域 ab initio研究
Tammie R Nelson1, Oleg V Prezhdo
1Department of Chemistry, University of Rochester, Rochester, New York 14627, United States.
Journal of the American Chemical Society
|February 5, 2013
概括
纯石墨烯表现出异常长寿命的电子激发,非常适合半导体应用. 氧化石墨烯更快地失去能量,但原始石墨烯显示能量损失缓慢,使其成为一个有前途的材料.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 计算化学计算化学
背景情况:
- 石墨烯及其衍生品是薄型,宽带间隙半导体,具有电子和能源应用的潜力.
- 高效的半导体材料需要长寿命的带隙激发和缓慢的非辐射能量损失到热量.
研究的目的:
- 确定纯和氧化石墨烯中电子激发的非辐射寿命和辐射线宽度.
- 了解影响石墨烯基材料能量损失机制的因素.
主要方法:
- 最先进的非adiabatic分子动力学模拟.
- 时间依赖密度函数理论 (TD-DFT) 的计算.
主要成果:
- 纯石墨烯具有非常长的非辐射衰变时间 (约. 100 ns) 的时间.
- 环氧和氧石墨烯的电子激发能量损失速度比原始石墨烯快10-20倍.
- 原始石墨烯的非辐射衰变由合到特定的振动模式 (1200 cm-1) 控制.
结论:
- 纯石墨烯的缓慢电子-声子能量损失使其成为半导体应用的优秀候选者.
- 氧化石墨烯由于更广泛的振动模式合,显示出更快的能量消散.
- 石墨烯衍生物为先进的材料设计提供可调节的电子和光学特性.
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