1. ●
Preparation of fluorescent Carbon Dot nanoparticles by thermal
processing to use as fillers in polyimide semiconductor.
●
Fabrication of Carbon-Dot polyimide flexible memory device.
●
Study of electrical, thermal and optical properties of the
nanocomposite and switching behaviour of memory device.
FT-IR STUDIES
Properties
●
Optically transparent and lightweight
●
Advantage of rich structural flexibility
●
Multi-dimensional stacking capability
Application
●
Integrated Organic device circuits
●
Production of high density and very
stable digital nonvolatile WORM and
volatile DRAM memory devices.
●
Plastic and Flexible electronic devices
CHARACTERIZATION OF
CARBON-DOT
2 gm citric acid is taken in a RB flask and
heated at 2200C for 30 mins to get
fluorescent carbon dots.
PROPERTIES OF C-DOT
POLYIMIDE
TRANSPARENCY STUDIES
Flexible and transparent polymer memory devices
Shivam Dubey a and Kuruvilla Joseph*b
a Indian Institute of Technology Guwahati, bIndian Institute of Space Science and Technology
Trivandrum
OBJECTIVES OF THE
STUDY
INTRODUCTION
FABRICATION OF MEMORY
DEVICE
CONCLUSION
Image showing the fluorescent C-dot in UV
light.
ELECTRICAL PROPERTIES
THERMAL
STABILITY
PREPARATION OF C-DOT
Fluorescence
Schematic diagram of the fabrication process for polymer memory device.
Illustration of preparation of Carbon dot-Polyimide film
Flexible and Transparent memory chip
Flexible DisplayFlexible Integrated Circuit
LIMITATIONS OF CONVENTIONAL
MEMORY DEVICES
●
Physical limitation of the resolution of the lithography patterns
●
High process cost
●
Limitation in use of large memory
●
Not appropriate for flexible and transparent electronics
2 gm citric acid Heating at 2200C Carbon Dot Fluorescence in
UV light
PROPERTIES
●
Good Conductivity
●
Photochemical stability
●
Benign chemical composition
●
Fluorescent
●
Suitable for chemical modification and surface passivation with various

organic, polymeric, inorganic or biological materials.
300 350 400 450
Absorption(A.U) Wavelength(nm)
Cdot
4000 3500 3000 2500 2000 1500 1000
Wavenumber (cm
-1
)
PI-CDOT
PI
%Transmittance(A.U.)
660 680 700 720 740 760 780 800
0
20
40
60
80
100
Wavenumber(cm
-1
)
PI-CDOT
PI
%Transmittance
0 100 200 300 400 500 600 700 800
40
50
60
70
80
90
100
%Weightloss
Temperature(
o
C)
PI-CDOT
PI
4000 3500 3000 2500 2000 1500 1000
%Transmittance(A.U.)
Wavenumber(cm
-1
)
CDOT
SAMPLE TRANSMITTANCE(%)
PI 80
PI + CARBON DOT 75
UV Transmittance spectra of pure polyimide and Carbon dot polyimide nanocomposite
●
Incorporation of carbon dot in polyimide resulted in a little decrease
●
in transparency.
●
It exhibits 75% of transmittance.
FTIR spectra of pure polyimide and Carbon dot polyimide nanocomposite
●
1650 cm-1 and 1560 cm-1 carbonyl stretching and N-H bending of amide
●
1500-1600 cm-1 Ionized carboxyl vibration mode of carboxyl groups
●
1360 and 1710 cm-1 C-O and C=O of carboxyl in Carbon dot
Same nature of both curves indicates that there is not much change in polyimide
structure after incarporation of Carbot dot.
UV spectra of Carbon dot FT-IR spectra of Carbon dot
SAMPLE SURFACE RESISTIVITY
PI 1012 Ω/sq.
Carbon dot-PI 105 Ω/sq.
Change in resistivity is observed from very low resistivity to
high resistivity which indicates the switching behaviour of memory
device
TGA curve of polyimide
REFERENCES
●
Thermal stability is decreased by
addition of carbon dots.
●
Exibits stability till high
temperature
1360 and 1710 cm-1 C-O and
C=O of carboxyl in Carbon dotAbsorption peak at 330nm
●
Carbon dot were synthesized by thermal processing method which show fluorescence property.
●
Transparent and flexible memory device was fabricated.
●
Carbon dot polyimide film is showing 75% UV visible trasmittance.
●
Electrical studies show a transition in surface resistivity, which shows switching behaviour of device.
●
Thermal studies show that carbon dot polyimide is temperature resistant till high temperature.
1)-Tadanori Kurosawa, Tomoya Higashihara and Mitsuru Ueda, Polym. Chem.,
2013, 4, 16–30
2)-Stefan Metz,* Raphael Holzer and Philippe Renaud, Lab on a Chip, 2001, 1,
29–34
AKNOWLEDGEMENT
Author thanks Najia KPP, IIST Trivandrum for guidance and Dr. JD Sudha, NIIST
Trivandrum for conductivity studies.