piezoelectricity

1. PIEZOELECTRICITY :
PRINCIPLE, MATERIALS
AND ITS APPLICATIONS
COURSE INSTRUCTOR
DR. VENKATA GIRISH GOTNUR
ASSISTANT PROFESSOR
SEST,UOH
PRESENTED BY
MAHFOOZ ALAM
M.TECH(MATERIALS ENGINEERING)
17ETMM10

2. Piezoelectric Effect
 Appearance of an electric potential across certain faces
of a crystal when it is subjected to mechanical pressure.
 The word originates from the greek word “piezein”, which
means “to press”.
 Discovered in 1880 by Pierre Curie in quartz crystals.
 Conversely, when an electric field is applied to one of
the faces of the crystal it undergoes mechanical
distortion.
 Examples --- Quartz, Barium titanate, etc.
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3. Conti….
 Bending materials to
generate electricity
 Apply voltage to
deform materials
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4. Internal working
 The effect is explained by the displacement of ions in
crystals that have a nonsymmetrical unit cell
 When the crystal is compressed, the ions in each unit cell
are displaced, causing the electric polarization of the unit
cell.
 Because of the regularity of crystalline structure, these
effects accumulate, causing the appearance of an electric
potential difference between certain faces of the crystal.
 When an external electric field is applied to the crystal,
the ions in each unit cell are displaced by electrostatic
forces, resulting in the mechanical deformation of the
whole crystal.
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5. Piezoelectricity
 displacement of electrical
charge due to the deflection
of the lattice in a naturally
piezoelectric quartz crystal
 The larger circles represent
silicon atoms, while the
smaller ones represent
oxygen.
 Quartz crystals is one of the
most stable piezoelectric
materials.
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6. Cont…
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7. Piezoelectric Coefficient
 It quantifies the volume change when a piezoelectric
materials is subjected to an electric field or polarization on
application of stress.
d=p/σ where p= polarization and σ is stress
 There can be many piezoelectric coefficient dxy .
the first subscript to d indicates the direction of polarization
in the material and second subscript say direction of stress
or alternatively.
e.g:- d33 induced polarization direction is 3 and applied sterss is also in direction 3
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8. Artificial materials
 polycrystalline, piezoceramics are man made
materials which are forced to become
piezoelectric by applying large electric field.
 high charge sensitivity.
 materials available which operate at 1000 F
(540 C).
 characteristics vary with temperature.
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9. Lead Free Piezoelectric materials
 Since 1950s, PbZr1-xTixO3 (PZT)-based ceramics have
drawn much attention because of their excellent
piezoelectric properties.
 They have been extensively utilized in almost all kinds of
piezoelectric devices.
 However, more than 60% toxic lead element in PZT exerts
pressure on the surrounding environment during their
preparation and processing.
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10.  Environment protection and human health concern is the
driving force to eliminate the lead from commercial
piezoelectric materials.
 As a result, there is an increasing interest in developing
lead-free piezoelectric with the aim of achieving an
equivalent or even higher piezoelectric response as those of
the lead-based ones.
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Cont…

11. Cont….
 In 2004, Saito et al. reported a peak piezoelectric constant d33 of
416 pC/N in the Li+-,Ta5+,andSb5+modified (K,Na)NbO3(KNN)
ceramics using the reactive templated grain growth (RTGG)
method1.
 KNN has become one of the most extensively investigated lead-
free piezoelectric systems [Figure 1a] because of its large d33
and a high Curie temperature (TC)
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12. Applications
Smart Ski (ACX)
Health monitoring
Inflatable Antennae
Flow sensors and
actuators
NASA Applications
•Electro-optical Device Technologies
•Precise positioning
•Switches
Multifunctional Membranes
•Antennas
•Reflectors
•Smart skins
•Tuning and positioning inflatable
structures
Biomedical
•Portable Artificial organs
•lightweight fetal heart monitor
•Ultrasonic imaging
•Tissue engineering 12

13. Piezoelectric Applications
 Capture the energy created by the runners on
special exercise machines - Green Microgym
in Portland, Oregon cut energy bills by 60 %
 Using piezoelectric technology under the dance
floor - Club Watt in Rotterdam, Holland
 Power a pair of night vision goggles used by
soldiers
 Just one minute of walking generates enough
energy to power a mobile phone for 30 minutes
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14.  In 2006, Japan East Railway Company installed piezoelectric floors in
an exit gate of their Tokyo Station. The 6 m2 piezoelectric floor was
reported to generate a maximum energy of 10KW s per day.
 In a pilot study carried out by Innowattech Ltd. in association
with Technion Israel Institute of Technology, a 10-m stretch of
piezoelectric generators were placed under a highway in Israel in
2009. The reported average power output was 2KWh, and the
obtained energy was stored in a battery beside the road.
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15. Challenges of Using
Piezoelectricity
 Maintaining batteries is a major
logistical and cost issue.
 One of the key aspects of vibrational
energy harvesting is the way it can be
tightly integrated into equipment.
 A major limitation of these advanced
materials is incorporating them into
very small-scale devices.
 As for the nanogenerators, we
need to raise the nanogenerator’s
output voltage. This will require
optimizing the electrode’s design
to reduce system capacitance. 15

16. Conclusion
 Piezoelectric phenomena can be easily understood.
 Materials which shows piezoelectric behavior can be
natural or artificial.
 Lead free piezoelectric materials is non toxic and
environmental friendly, so it can be used as green
technology materials.
 There are wide range of application of these
materials which can save our non renewable sources
of energy.
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17. THANK YOU
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