Annealing-induced structural changes of carbon onions: High-resolution transmission electron microscopy and Raman studies

Raman spectroscopy study of the transformation of the carbonaceous skeleton of a polymer-based nanoporous carbon along the thermal annealing pathway

“…This is in line with previous observations for multi-crystalline graphite [30], nanographites [40,41], defective graphenes [24-26, 33, 34], soots [39], carbon blacks [31] and polymer derived carbons [31]. Fig.…”

“…The use of multi-wavelength laser sources can also help improve deconvolution reliability as the fitted results can be checked against the expected excitation energy dispersive behaviour [23,31,32,[40][41][42][43].…”

“…Of interest here are those that have been experimentally observed for disordered carbons and are thought to be related to defects, namely the D' [22,[30][31][32][33][34], A [35][36][37][38][39][40][41] and TPA [40][41][42] bands. Similar to the D band, the D' band is caused by defect-induced breaking of translational symmetry [32].…”

“…non-crystalline sp 3 -dominated carbon) [35][36][37], whilst more recent theoretical and experimental studies [38][39][40][41] suggested it may come from non-hexagonal ring defects in the sp 2 system. The TPA band has been linked to both sp 2 -based transpolyacetylene-like chains (see Fig.…”

“…The TPA band has been linked to both sp 2 -based transpolyacetylene-like chains (see Fig. 1) at layer edges [42] and, more recently, to zigzag edges [40,41], although this assignment is questionable given the contrast between the abundance of zig-zag edges in these materials and the relatively low intensity of TPA bands that appear in their Raman spectra.…”