The document discusses nantennas, which are nanoscopic antennas that can convert solar radiation into electricity. Nantennas address many limitations of traditional photovoltaic cells. They work by absorbing electromagnetic waves from solar radiation and thermal earth radiation. This induces an alternating current in the nantenna, which is then rectified into direct current using a diode. Nantennas show promise for applications like self-charging batteries and could be mass produced inexpensively using roll-to-roll manufacturing. Future research aims to improve rectifier efficiency and upscale the technology for widespread use.

2. SARAN KUMAR.S
S5EEE
ROLL NO: 45
REG. NO :11031097
GPTC
ATTINGAL

4. HISTORY
 In the middle of 19th century, a conventional method, called
photovoltaic cell is introduced to harvest solar energy to
produce electricity.
 This PV cells works under the principle of photoelectric effect,
even though the technology is now extensively used it has
some notable limitations.
 To overcome the limitations of photovoltaic cell studies have
conducted to find a new device which converts solar energy to
electricity.
 From there, the idea of nanoscopic rectifying antenna started.
 In 1966, GUANG H.LIN was the first to report resonant light
absorption by a fabricated nano structure and rectification of
light with frequencies in the visible light,since then researches
on nantenna is ongoing.

5. CURRENT TECHNOLOGY :
 Photovoltaic Technology.
Photon
DC
CURRENT
electron–hole
pairs

6. LIMITATIONS OF PV TECHNOLOGY :
• Band gap (heat loss, reduces efficiency)
• Expensive for large scale (multi junction) manufacturing
• PV is operational only during daylight hours.
• Delivers DC power
• Low efficiency
• Requires direct incidence(perpendicular to surface) of solar
radiation for optimum efficiency.

8. “The Infinite Power of the Sun”
Single day provides enough energy for 27 years
{~ 127.518*10^15 W (127 PW) sun energy strikes earth/1hour.}
~30% Reflected
~19% Absorbed Atmosphere
~51% Absorbed by Earth

9. INTRODUCTION TO NANTENNA:
 A nantenna (nano antenna) is a nanoscopic rectifying
antenna. Nantennas are used for converting solar
radiation to electricity.
 Based on antenna theory, a nantenna is a EM
collector that can absorb any wavelength of light
efficiently provided that the size of the nantenna is
optimized for that specific wavelength.
 Ideally, nantennas would be used to absorb light at
wavelengths between 0.4–1.6 μm because these
wavelengths have high energy and make up about 85% of
the solar radiation spectrum.

11. ELECTRONS’
MOTION
PRODUCES A.C
LOAD
NANTENNA
DIRECT
CURRENT
RECTIFIES/ COLLECTS
ELECTROMAGNETIC WAVES
SUNLIGHT
DIODE(RECTIFIER)

12. Design Overview
• Initial design of Nantennna was based
on scaling of radio frequency antenna
theory
• Analytical model – RLC Circuit derived
• Nantenna consists of an antenna layer, a
dielectric resonance layer, and a optical
reflector/ground plane
• Physical geometry tunes antenna and
spectral response
Ground plane - reflector
Dielectric resonance layer
Nantenna Structure
Antenna & RLC

13. A TYPICAL NANTENNA:
( Single loop metal Nantenna
)
( Array of loop Nantenna )

14. THEORY OF NANTENNAS:
 The incident light causes electrons in the
nantenna to move back and forth at the same
frequency as the incoming light.
 This is caused by the oscillating electric field of
the incoming EM wave. The movement of electrons
causes an alternating current in the nantenna
circuit.

15. THz CURRENT
Typical electromagnetic radiation
patterns of antenna
( Flow of THz currents to feed point of antenna.
Red represents highest concentrated E field )
The e-field is clearly concentrated at the center feed-point. This provides
a convenience point to collect energy and transport it to other circuitry for
conversion.

16. • Light propagates as an EM wave at certain frequency.
• Captured by a Nanoantenna
• Absorption occurs at Nantenna
resonance frequency.
• Induces a back and forth movement
of free electrons in Nantenna.
• THz current flows toward Nantenna
feed-point.
• This provides a convenience point to
collect and transport energy to other
circuitry for conversion (AC to DC).
• Diode is embedded in feed-point to
rectify signal.
THEORY OF OPERATION

17.  The NECs can be configured as FSS (frequency selective
surfaces) to efficiently absorb the entire solar spectrum.
 Nantenna capture electromagnetic energy from
naturally occurring solar radiation and thermal earth
radiation.
 Rather than generating single electron-hole pairs as
in the PV, the incoming EM field induces a time-
changing current in the Nantenna.
 To convert this AC into direct current, the AC is
rectified using diode. The resulting DC current can then
be used to power any external load.

18. ( Square FSS element and its RLC circuit analog )
ANALYTICAL MODEL – RLC CIRCUIT:
 The metal loops give inductance to the NEC as thermally-
excited radiation induces current.
 The gaps between the metallic loops and the gap within the loop
compose capacitors with a dielectric fill.
 A resistance is present because the antenna is composed of lossy
metallic elements on a dielectric substrate.
 The resulting RLC circuit has a resonance “tuned” filter
behaviour.

19. COMPONENTS OF A NANTENNA:
 The nantenna consists of three main parts:
1.The ground plane
2.The optical resonance cavity
3.The antenna.
Ground plane - reflector
Dielectric resonance cavity layer
Antenna

20. MANUFACTURING OF NANTENNA:

21. The antenna absorbs the EM wave, the ground plane
acts to reflect the light back towards the antenna, and the
optical resonance cavity bends and concentrates the light
back towards the antenna via the ground plane.
The NEC-to-ground plane separation (cavity) acts as a
transmission line that enhances resonance. The thickness of
the standoff layer is selected to be a ¼ wavelength to ensure
better efficiency.
( path of incident wave )
WHY THIS STRUCTURE ??? :

22. LITHOGRAPHY & R2R:
1. LITHOGRAPHY (laboratory processing, small scale )
2. R2R (master pattern, large scale )
Roll to Roll Manufacturing
Equipment
Manufacturing Cost:~ $0.50-1.00/ft2

23. LARGE-SCALE MANUFACTURED SAMPLES:
SEM image of polymer replicas made
from wafer master template
Flexible Structures

24. APPLICATIONS OF NANTENNA
• Addresses many limitations of PVs.
• Utilize untapped infrared parts of spectrum
(Solar radiation & Thermal earth radiation)
• Can be inexpensively mass produced.
•DNA Nanoantenna & Cancer Fighting Lasers.

25. Many Diverse Applications :
• Nanoantenna “skins” e.g. self-charging AA battery design,car,laptop
• Economically scales to large infrastructure (homes, businesses)

26. DISADVANTAGES OF NANTENNAS:
 One of the major limitations of nantennas is the
frequency at which they operate. The high frequency of
light makes the use of typical Schottky diodes
impractical i.e. more advanced diodes are necessary to
operate efficiently at higher frequencies.
 Current nantennas are produced using electron beam
(e-beam) lithography. This process is slow and relatively
expensive because parallel processing is not possible with
e-beam lithography. (Can be eliminated by roll-to-roll
manufacturing method.)

27. FUTURE RESEARCH AND GOALS:
A rectifier must be designed that can properly turn the
absorbed light into usable energy. Researchers currently hope
to create a rectifier which can convert around 50% of the
nantenna's absorption into energy.
 Nantenna could be designed to work by absorbing the infrared
heat available in the room and producing electricity which could
be used to further cool the room.
Another focus of research will be how to properly upscale the
process to mass-production. New materials will need to be
chosen and tested that could be used with a roll-to-roll
manufacturing process.

28. REFERENCES:
[1] A. Csaki, F. Garwe, A. Steinbruck, A. Weise, K. Konig, and W. Fritzsche, "Localization of
laser energy conversion by metal nanoparticles basic effects and applications - art.
No.61911K," in Biophotonics and New Therapy Frontiers, vol. 6191, SPIE , 2006, pp. K1911-
K1911.
[2] Alda, J. Rico-García, J. López-Alonso,and G. Boreman, "Optical antennas for nano-
photonic applications," Nanotechnology, vol. 16, pp. S230-4, 2005
[3]Ansoft High Frequency Structure Simulator v10 User’s Guide, Ansoft Corporation,
(2005)
[4] B. A. Munk, “Frequency Selective Surfaces: Theory and Design”. NewYork: Wiley, 2000,
pp. 2–23.
[5] B. Monacelli, J. Pryor, B. Munk, D. Kotter, G. Boreman, “Infrared Frequency Selective
Surfaces: Square loop versus Square-Slot Element Comparison” AP0508-0657, Aug 2005
[6] Guy J. Consolmagno and Martha W. Schaefer, World‘s Apart: A Textbook in Planetary
Sciences (1994) Englewood Cliffs, NJ: Prentice Hall.

29. ANY DOUBTS

31. Material
Energy gap (eV)
0K 300K
Si 1.17 1.11
Ge 0.74 0.66
InSb 0.23 0.17
InAs 0.43 0.36
InP 1.42 1.27
GaP 2.32 2.25
GaAs 1.52 1.43
GaSb 0.81 0.68
CdSe 1.84 1.74
CdTe 1.61 1.44
ZnO 3.44 3.2
ZnS 3.91 3.6

32. Average instantaneous power emitted by the Sun = 3.8 x 1023 kW
Solar energy per year = 3.33108 x 1027 kWh/year
Volume of Earth’s electrical consumption (2008) = 143,851 TWh/year
Solar power hitting Earth’s atmosphere = 1,366 W/m2
Percentage of power reaching Earth’s surface = 18%
Solar power hitting Earth’s surface = 250,000,000 W/km2
Earth’s surface area = 510,072,000 km2
Total average solar power hitting Earth = 127.518*10^15W
Hours per year = 8,766 h/y
Total solar energy hitting Earth per year = 1,117,822,788 TWh/year

33. Bio-Inspired Nanoantennas For Light Emission
Just as radio antennas amplify the signals of our mobile phones and televisions, the same principle can apply to light. For the first time,
researchers from CNRS and Aix Marseille Université have succeeded in producing a nanoantenna from short strands of DNA, two gold
nanoparticles and a small fluorescent molecule that captures and emits light. This easy-to-handle optical antenna is described in an article
published in Nature Communications on 17 July 2012. This work could in the longer term lead to the development of more efficient light-
emitting diodes, more compact solar cells or even be used in quantum cryptography.
Schematic representation of a nanoantenna formed of two gold nanoparticles linked by a DNA double strand and supplied by a single
quantum emitter
Since light is a wave, it should be possible to develop optical antennas capable of amplifying light signals in the same way as our televisions
and mobile phones capture radio waves. However, since light oscillates a million times faster than radio waves, extremely small nanometer
(nm) sized objects are needed to capture such very rapid light waves. Consequently, the optical equivalent of an elementary antenna (of
dipole type) is a quantum emitter surrounded by two particles a thousand times smaller than a human hair.
For the first time, researchers from the Langevin and Fresnel1 Institutes have developed such a bio-inspired light nanoantenna, which is
simple and easy to handle. They grafted gold particles (36 nm diameter) and a fluorescent organic colorant onto short synthetic DNA strands
(10 to 15 nm long). The fluorescent molecule acts as a quantum source, supplying the antenna with photons, while the gold nanoparticles
amplify the interaction between the emitter and the light. The scientists produced in parallel several billion copies of these pairs of particles (in
solution) by controlling the position of the fluorescent molecule with nanometric precision, thanks to the DNA backbone. These characteristics
go well beyond the possibilities offered by conventional lithography techniques currently used in the design of microprocessors. In the longer
term, such miniaturization could allow the development of more efficient LEDs, faster detectors and more compact solar cells. These
nanosources of light could also be used in quantum cryptography

34. ( Bow-tie Nantenna ) ( Array of bow-tie Nantenna )

35. Content overview
1. Why Nantenna ?
2. Introduction to Nantenna.
3. Theory or Nantenna.
4. Theory of operation.
5. Analytical model (RLC Model).
6. Manufacturing of Nantenna.
7. Benefits and applications.
8. Limitations of nantennas.
9. Future research and goals.
10. References