50
K. Illath et al.
Fig. 11 Effect of reducing agent on size distribution of MNPs; TEM images of Au NPs synthesized
with citrate concentration of a 0.067, b 0.133 and c 0.200% and its particle distribution in d, e and
f respectively, g corresponding absorbance spectrum. TEM images of Au NPs synthesized with
NaBH 4 concentration of h 0.067, i 0.133 and j 0.200% and its particle distribution in k, l and
m respectively, n corresponding absorbance spectrum. All scale bar in TEM images is 100 nm and
inset is 10 nm. Reproduced from [69] under a creative commons license deed (https://creativecomm
ons.org/licenses/by-nc-nd/4.0/)
abundance of triangular NPs. Hence the tendency of the spectrum with increasing
seed age is the occurrence of the second peak with redshift and increased intensity
of absorption. The findings from the absorbance spectrum are further analysed with
the TEM images, as shown in Fig. 12b–e. With 0 min seed age, synthesized NPs
are spherical, and the particle solution has a yellow colour. With 15 min, anisotropic
structures such as rods, triangles, and few spheroidal shapes are seen, and the particle
solution is red. The corresponding histogram of shapes revealed that nanorods are
abundant with 53.9%, spheres with 33.6%, and the remaining constitute triangle and
other shapes. With 30 min seed age, triangular shapes are more compared to rods,
spherical, and spheroids [31]. It has also been investigated the effect of seed ageing
K. Illath et al.
Fig. 11 Effect of reducing agent on size distribution of MNPs; TEM images of Au NPs synthesized
with citrate concentration of a 0.067, b 0.133 and c 0.200% and its particle distribution in d, e and
f respectively, g corresponding absorbance spectrum. TEM images of Au NPs synthesized with
NaBH 4 concentration of h 0.067, i 0.133 and j 0.200% and its particle distribution in k, l and
m respectively, n corresponding absorbance spectrum. All scale bar in TEM images is 100 nm and
inset is 10 nm. Reproduced from [69] under a creative commons license deed (https://creativecomm
ons.org/licenses/by-nc-nd/4.0/)
abundance of triangular NPs. Hence the tendency of the spectrum with increasing
seed age is the occurrence of the second peak with redshift and increased intensity
of absorption. The findings from the absorbance spectrum are further analysed with
the TEM images, as shown in Fig. 12b–e. With 0 min seed age, synthesized NPs
are spherical, and the particle solution has a yellow colour. With 15 min, anisotropic
structures such as rods, triangles, and few spheroidal shapes are seen, and the particle
solution is red. The corresponding histogram of shapes revealed that nanorods are
abundant with 53.9%, spheres with 33.6%, and the remaining constitute triangle and
other shapes. With 30 min seed age, triangular shapes are more compared to rods,
spherical, and spheroids [31]. It has also been investigated the effect of seed ageing