题　目：Bottom-up analytical approach of X-ray diffraction patterns and Raman scattering of carbon materials 

报告人：Prof. Pascal Puech（ University of Toulouse, France） 

时　间：2023年6月19日（周一）10:00-12:00 

地　点：李薰楼468会议室 

 

摘要:

In this presentation, we will discuss two experimental techniques currently used to characterize carbon materials and show what can be learned from them. The X-Ray diffraction applied from low to highly organized carbon gives in routine the crystallite size of the domain even if some discrepancies exist between values deduced from several peaks. Calculating diffraction patterns from GPU to obtain calibrated functions used to fit experimental data is a very powerful way to go deeper into the interpretation and knowledge about how carbon materials structurally behave upon increasing carbonisation and graphitisation temperatures. For example, the formation of AB pairs around 2000°C is evidenced, the various stacking sequences (including rhomboedral) present in the average crystallite are identified, and the existence of peaks in the low scattering angle range in poorly organized carbons is explained by interference features specific to low dimension crystallites. The case of natural graphite will be also discussed to know how to proceed in order to have the characteristics. Raman spectroscopy is another powerful technique for understanding carbon materials as, even for small amounts, a signal is obtained. Two examples are addressed: (1) poorly organized carbons where the situation is complex and only trends seem to be accessible for D and G linewidth, intensity, and position and (2) D’band to track the sp2->sp3 transformation for mono/bi layer graphene.