Supplementary information
Laser-induced white-light emission from graphene ceramics – opening a
band gap in graphene
100000
(002)
26.60
d = 0.335 nm
Intensity (arb. units)
80000
60000
40000
(004)
(020/111)
54.61
d = 0.21/0.20 nm d = 0.168nm
20000
10
15
20
25
30
35
40
45
50
55
60
2Theta []
Figure 1s The powder X-ray diffraction pattern of the graphene nanoplatelets (GNPs). The
GNPs were characterized by surface areas of 600 – 750 m2/g, 4-5 graphene layers with
average thickness of 8 nm and the single particle diameter less than 2 microns. Reflection at
the 2Θ = 26.6° suggest that stacked graphene layers are present in the material.
(b)
(a)
1
Figure 2s Representative images of graphene nanoplatelets acquired via transmission electron
microscopy (TEM). Graphene plates and some carbonaceous amorphous phase can be clearly
observed.
Figure 3s SEM images of a graphene green body (a) and a ceramic (b) sintered at 8 GPa and
500°C. There are visible differences between the cold-pressed (green body) and sintered
ceramics. After pressing, the number of pores and their sizes significantly decreased, and the
ceramic became consolidated with a much smoother surface. A representative image of a
graphene ceramic sample is presented as an inset in Figure 3b.
2
Figure 4s The CIE 1931 chromaticity coordinates calculated for the graphene ceramics after
excitation at various photon energies: (a) 2.6 eV (476 nm), (b) 2.5 eV (488 nm), (c) 2.4 eV
(514 nm), (d) 1.5 eV (808) nm and (e) 1.2 eV (976 nm).
3