L*a*b* values of the silica crystal films, with and without graphene oxide inclusion^a.

Samples	CIE L*	CIE a*	Color shift related to CIE a*	CIE b*	Color shift related to CIE b*
198.8 nm	49.15	0.68		−29.51
198.8 nm + GO	45.74	0.83	Red shift	−23.94	Yellow shift
224.3 nm	68.25	−36.14		2.99
224.3 nm + GO	66.80	−28.02	Red shift	−4.43	Blue shift
232.0 nm	67.02	−23.32		−1.07
232.0 nm + GO	61.75	−18.83	Red shift	−2.74	Blue shift
258.7 nm	77.03	−11.85		12.81
258.7 nm + GO	74.01	−10.58	Red shift	5.94	Blue shift
288.2 nm	58.62	15.23		2.77
288.2 nm + GO	58.31	10.95	Red shift	−0.94	Blue shift
295.3 nm	74.12	1.08		−9.32
295.3 nm + GO	72.59	0.71	Green shift	−9.12	Blue shift

^aThe L* values of the crystal films do not change significantly with respect to particle size. This indicates that films of all particle sizes exhibit a darker color compared with the pure SiO₂ particle films which have no obvious change in lightness upon the incorporation of graphene oxide. The a* and b* values indicate the chromatic change in terms of the designated color coordinates and the percentage distribution of the three primary colors.