Published on: Mar 4, 2016
Transcripts - Polymer memory
M.Sc. (Polymer Science & technology)
DEPT. OF APPLIED CHEMISTRY.
ALIGARH MUSLIM UNIVERSITY,ALIGARH
What is Polymer memory?
A leading technology in memory device development
Made out of electrically-conducting polymer (PEDOT)
Relatively denser and cheaper compared to flash memory
Advanced Micro Devices of Sunnyvale, California, is working
with Coatue, a startup in Woburn, Massachusetts, to develop
chips that store data in polymers rather than silicon.
What is a PEDOT?
A conducting polymer based on 3,4-
ethylenedioxythiophene (EDOT monomer)
optical transparency in its conducting state
PEDOT has moderate band gap and low redox potential
PEDOT coatings possess high stability over different
charge and discharge cycles and can be electrogenerated
directly on a conductive support
• PEDOT nanofibers are produced from vanadium pentoxide nanofibers by a
nanofiber seeding method.
1. EDOT is dissolved in an aqueous solution of camphorsulfonic acid (CSA)
and a vanadium pentoxide nanofiber sol-gel
2. Radical cationic polymerization is initiated by addition of ammonium
3. The resulting polymer precipitates from solution and has a general
4. Washing with dilute HCl removes the vanadium compound.
5. The presence of the vanadium pentoxide seeds make the difference between
the formation of PEDOT nanofibers (100 to 180 nanometer diameter and
one to several micrometres long)
6. The formation of a more conventional granular morphology.
7. When applied to a solid substrate such as PET, PEDOT non-woven films
have slightly less optical transparency and about half the conductance of
commercial PEDOT:PSS / PET films
Synthesis of PEDOT
PEDOT coatings possess high stability over
different charge and discharge cycles and
can be electrogenerated directly on a
The material is a blend of
A negatively charged polymer called PSS-
A positively-charged one called PEDT+
Anti-static coating on camera film
A photo-sensitive agent
Conductivity of PEDOT
• The device sandwiches a blob of a conducting polymer
called PEDOT (POLYETHYLENE DIOXYTHIOPENE)
• Stores a megabit of data in a millimeter-square device -
10 times denser than current memories
• Turning the polymer into an insulator involves a
permanent chemical change, meaning the memory can
only be written to once
Architecture of Polymer
• Each polymer is sandwiched
between two electrodes which
acts as memory cell
• A voltage is applied between top
and the bottom electrodes
• Memory is represented as space
charges in the polymers that are
detected using electrical pulses
• stores information in an entirely different manner than
• store data based on the polymer’s electrical resistance
• Application of an electric field to a cell lowers the
polymer’s resistance, thus increasing its ability to
• the polymer maintains its state until a field of opposite
polarity is applied to raise its resistance back to its
• The different conductivity states represent bits of
Read / Write Data
•To store the memory,
it use the wires and
the diode surrounding
the PEDOT blob to
run either a high or a
low current through it.
•To read the memory,
they run current
through the top wire
and measure the
current in the bottom
•No current means the
bit is a zero, and vice
Features of Polymer Memory
• Data stored by changing the polarization of the polymer
between metal lines
• Zero transistors per bit of storage
• Microsecond initial reads. Write speed faster than
NAND and NOR Flash
• Simple processing, easy to integrate with other CMOS
• No cell standby power or refresh required
• Operational temperature between -40 and 110°C
• Polymer memory layers can be stacked This enable to
achieve very high storage capacity.
• Memory is Nonvolatile
• Fast read and writes speeds
• Very low cost/bit, high capacity per rupee
• Low power consumption
• Easy manufacture, use ink-jet printers to spray liquid-
polymer circuits onto a surface
• 10xFaster than conventional memory devices
Advantages of Polymer memory?
• One million bits of information could fit into a square
millimeter of material the thickness of a sheet of paper.
A block just a cubic centimeter in size could contain as
many as 1,000 high-quality digital images
• Scientists suggest, and producing it wouldn't require
high temperatures or vacuum chambers.
• Unlike a CD, reading data stored on this memory block
does not involve any moving parts or a laser. Instead it
can be plugged directly into a circuit.
• It’s a very cheap technology which gives it a upper hand
over other technology.
• A PEDOT-based machine could solve the problem of
virus hackers, who rely on the fact they cannot afford to
leave a trace out of fear of being caught for their dirty
work. With PEDOT-based solutions hackers would not
be able to erase their IP addresses.
Facts and Fiction
• It can be read many times but it can be write only ones
• The biggest challenge is developing production
• This technology is still under research, so it will take
time to launch in the market
Limitations of Polymer memory?
WORM (WRite Once Read Many) type
peRManent stORage such as in
• It is 10 times denser than current magnetic memories.
• Store mega-bit of data in millimeter-square device.
• Data can’t be rewritten so suitable for permanent storage
• It requires only few transistors.
• It cost about 5% as much to manufacture compared to
• Retain data without power.
• Zhang, Xinyu; MacDiarmid, Alan G.; Manohar, Sanjeev K. (2005).
"Chemical synthesis of PEDOT nanofibers". Chemical Communications
(42): 5328–30. doi:10.1039/b511290g. PMID 16244744
• Unfolding space, memory by N. Nagaraj Financial Daily from THE HINDU
group of publications
• Technical paper, "Memory Device Applications of a Conjugated Polymer:
Role of Space Charges," Journal of Applied Physics, February 15, 2002
• . www.detnews.com
• A. Prakash, J. Ouyang, and J. Lin, “Polymer memory device based
on conjugated polymer and gold nanoparticles,” J. Appl. Phys., vol.
100, no. 5, pp. 1–5, 2006
• C. Perlov, W. Jackson, C. Taussig, S. Mo, and S. R. Forrest, “A
polymer / semiconductor write-once read-many-times memory,”
Nature, vol. 426, no. November, 2003
• MIT Technology Review 03 / 02 –Improved Memory
• MIT Technology Review 09 / 02 – Polymer Memory