nanoparticles have displayed the higher rate of dispersion in polymer matrix and act
as an efficient material for ink-free patterned compound. The as formed particles
have further been used for the detection of latent fingerprints of living beings. The
process was found to be quite simple and affordable for the generation of large
scaled C-dots. The technique employed in this work has provided the stability and
clarity in latent fingerprints methodologies employed so far. The other advantage is
the non-toxic nature of the employed material and better control over the colour
tuning of samples.
7.7
Characteristic Properties of C-Dots
The zero dimensional with sp
2 hybridized carbon-based nanoparticles with size in
the range of 2–10 nm and having quasi-spherical shape and amorphous nature are
generally termed as carbon dots. In certain cases, the group of carbon dots with small
amount of N, O or H are also came under the category of carbon quantum dots (Kaur
et al. 2018; Muhulet et al. 2018; Torres et al. 2019). The presence of surface
modifiers over C-dots has provided them good water solubility and made them
effective in water treatment application (Hasija et al. 2019; Lin et al. 2018). The
chemical features of C-dots are mainly dependent over the nature of the synthetic
procedure and the nature of the starting source for preparation of C-dots. The
difference of size range made graphene oxide and carbon dots two separate materials
in nanotechnology. Otherwise their physical and chemical structures are comparable
with each other. The X-ray diffraction patterns have displayed characteristic peaks in
the region of 2θ ¼ 20 to 26
with interlayer spacing distance value of around 0.3 and
0.38 nm, respectively. These values have confirmed the similarities of C-dots with
graphene oxide. In addition, the existence of broad diffraction peaks in case of
C-dots has clearly pointed out the existence of amorphous character in C-dots (Singh
et al. 2019a; Huo et al. 2019). The mechanistic behavior of optical and
luminescemce properties in C-dots is very attractive and considered as the most
researched topic amongst the scientist (Ling et al. 2017; Peng et al. 2018). It has
mainly been believed that C-dots have displayed a characteristic peak between
230 and 270 nm and 300 and 340 nm. These two peaks are mainly aroused due to
the π!π* and n!π* transitions in C-dots, respectively. The variation in the peak
position has mainly associated with the existence of mixture of sp
2 and sp
3
hybridized carbon atom in C-dots. The variation in the number and their respective
distribution in the C-dots have produced direct impact over the optical properties of
C-dots. In addition, the presence of quantum confinement effect and surface defects
with the existence of aromatic kind of structure has also contributed towards the
optical properties of C-dots. Along with optical properties, the presences of radioactive recombination of excitons and nature of surface defects in C-dots have generated
multicolour fluorescence emission properties in C-dots (Ding et al. 2016). The
existence of emissive traps in C-dots has produced the emission peaks in region of
320 to 480 nm. The well-known blue to green to yellow emissions is quite common
in C-dots. The changes in the size, surface properties and defects in C-dots are
178
S. Chaudhary and P. Chauhan
as an efficient material for ink-free patterned compound. The as formed particles
have further been used for the detection of latent fingerprints of living beings. The
process was found to be quite simple and affordable for the generation of large
scaled C-dots. The technique employed in this work has provided the stability and
clarity in latent fingerprints methodologies employed so far. The other advantage is
the non-toxic nature of the employed material and better control over the colour
tuning of samples.
7.7
Characteristic Properties of C-Dots
The zero dimensional with sp
2 hybridized carbon-based nanoparticles with size in
the range of 2–10 nm and having quasi-spherical shape and amorphous nature are
generally termed as carbon dots. In certain cases, the group of carbon dots with small
amount of N, O or H are also came under the category of carbon quantum dots (Kaur
et al. 2018; Muhulet et al. 2018; Torres et al. 2019). The presence of surface
modifiers over C-dots has provided them good water solubility and made them
effective in water treatment application (Hasija et al. 2019; Lin et al. 2018). The
chemical features of C-dots are mainly dependent over the nature of the synthetic
procedure and the nature of the starting source for preparation of C-dots. The
difference of size range made graphene oxide and carbon dots two separate materials
in nanotechnology. Otherwise their physical and chemical structures are comparable
with each other. The X-ray diffraction patterns have displayed characteristic peaks in
the region of 2θ ¼ 20 to 26
with interlayer spacing distance value of around 0.3 and
0.38 nm, respectively. These values have confirmed the similarities of C-dots with
graphene oxide. In addition, the existence of broad diffraction peaks in case of
C-dots has clearly pointed out the existence of amorphous character in C-dots (Singh
et al. 2019a; Huo et al. 2019). The mechanistic behavior of optical and
luminescemce properties in C-dots is very attractive and considered as the most
researched topic amongst the scientist (Ling et al. 2017; Peng et al. 2018). It has
mainly been believed that C-dots have displayed a characteristic peak between
230 and 270 nm and 300 and 340 nm. These two peaks are mainly aroused due to
the π!π* and n!π* transitions in C-dots, respectively. The variation in the peak
position has mainly associated with the existence of mixture of sp
2 and sp
3
hybridized carbon atom in C-dots. The variation in the number and their respective
distribution in the C-dots have produced direct impact over the optical properties of
C-dots. In addition, the presence of quantum confinement effect and surface defects
with the existence of aromatic kind of structure has also contributed towards the
optical properties of C-dots. Along with optical properties, the presences of radioactive recombination of excitons and nature of surface defects in C-dots have generated
multicolour fluorescence emission properties in C-dots (Ding et al. 2016). The
existence of emissive traps in C-dots has produced the emission peaks in region of
320 to 480 nm. The well-known blue to green to yellow emissions is quite common
in C-dots. The changes in the size, surface properties and defects in C-dots are
178
S. Chaudhary and P. Chauhan