The document discusses the use of nanotechnology for renewable energy generation. It describes how dye-sensitized solar cells use nanostructures to absorb sunlight more efficiently and cheaply than traditional silicon-based solar cells. The document also discusses how solar cells work by absorbing photons that excite electrons, generating electricity, and how not all absorbed light is converted. Finally, it provides an overview of natural energy sources like hydrocarbons and their effects compared to more sustainable renewable sources like solar, wind, and biomass that are being advanced through nanotechnology approaches.

1. “NANO BASED TECHNOLOGY FOR RENEWABLE ENERGY
GENERATION”
MR. ANIL KUMAR
M.PHIL./PH.D. NANOSCIENCE, (2012-13)
CENTRE FOR NANOSCIENCE, CUG, SEC-30, GANDHINAGAR, GUJARAT1
kmr.nano@yahoo.com

2. Contents
Introduction of Renewable Energy
Solar Electric Power Plants
What is a Photovoltaic Cell
How PV Cells Work
Dye-Sensitized and Silicon-based Solar
Cells Compared
Dye-Sensitized Solar Cells
So What Does this Mean for Solar Cells
Absorption of Light by Ionic
Compounds
Absorption of Light by Atoms
But Not All Energy is Converted
Application of Energy
Natural Forming sources of Energy,
Application and effects
Renewable sources of Energy,
2
Application and effects

3. Introduction of Renewable Energy
 Nanotechnologies have significant potential to assist
economies in meeting their energy efficiency goals, enabling
adoption of new approaches, techniques and materials with a
wide range of applications, from efficient usage of traditional
energy sources to development and implementation of new
generation technologies based on renewable sources.
 The nanotechnology impact is especially important for
renewable energy, which together with energy efficiency are
pillars of sustainable energy policy. 3

4. Solar Electric Power Plants
• Main types:
1. Solar thermal
energy
• Has mirrored surface
that reflects sunlight Array of mirrored solar collectors at
to heat up liquid to FPL Energy site in California
make steam to
generate electricity
2. Photovoltaic
• Uses photovoltaic
cells that absorb
direct sunlight
Concentrated solar collector (parabolic)
4
Sources: http://en.wikipedia.org/wiki/Solar_energ , http://www.fplenergy.com/portfolio/solar/facts.shtml#glance

5. What is a Photovoltaic Cell?
• Is a device of generating electrical power by converting solar radiation into
direct current electricity using semiconductors that exhibit the photovoltaic
effect.
• Photovoltaic power generation employs solar panels composed of a number
of solar cells containing a photovoltaic material.
• Materials presently used for photovoltaics include monocrystalline silicon,
polycrystalline silicon, amorphous silicon, cadmium telluride, and copper
indium gallium selenide or sulfide….. etc.
How PV Cells Work?
1. Photons in sunlight hit the solar panel and are absorbed by
semiconducting materials, such as silicon.
2. Electrons (negatively charged) are knocked loose from their atoms,
allowing them to flow through the material to produce electricity.
3. An array of solar cells converts solar energy into a usable amount of direct
current (DC) electricity.
5

6. Dye-Sensitized and Silicon-based Solar
Cells Compared
• Dye-Sensitized “Nano” • Traditional “Single-crystal silicon”
1. Relatively 1. Expensive
inexpensive 2. Long return
2. Short return on on investment
investment
6
Sources: http://www.imo.uhasselt.be/polytech/images/zonnecel1.jpg, http://www.norfolksolar.co.uk/img/system.gif

7. Dye-Sensitized(“nano”) Solar Cells
• Relatively inexpensive
1. Made in non-vacuum
setting mainly at room
temperature
2. Relatively simple
manufacturing process
• Need little TLC
1. Thin, lightweight, flexible
• Short return on investment
1. Takes approx 3 months to
produce energy savings
equivalent to cost of
production
7
Source: http://www.imo.uhasselt.be/polytech/images/zonnecel1.jpg

8. So What Does this Mean for Solar Cells?
• In dye-sensitized solar
cells…
– Talk about highest
occupied molecular
orbital (HOMO) and
lowest unoccupied
molecular orbital
(LUMO)
• In single-crystal silicon
solar cells…
– Talk about “conduction
band” (excited states) and
“valence band” (ground
states) 8

9. Absorption of Light by Ionic Compounds
• Electrons can
jump between
“bands”
• Incident light with
energy ≥ than the
“band gap” energy
can be used to
excite the
electrons
9
Source: Image adapted from http://www.3dchem.com/molecules.asp?ID=135#

10. Absorption of Light by Atoms
• Absorption occurs only when the energy of
the light equals the energy of transition of
an electron
Single electron
transition in an
isolated atom
10
Sources: http://members.aol.com/WSRNet/tut/absorbu.htm, http://csep10.phys.utk.edu/astr162/lect/light/absorption.html

11. But Not All Energy is Converted
• Like chloroplasts in plants, solar cells can only
absorb specific wavelengths of light.
• In both, light that isn’t absorbed is either
transmitted through or reflected back.
• Whether a certain wavelength of lights gets
absorbed depends on its energy.
Chlorophyll molecules
absorb blue and red
light, but reflect green
light
11
Source: http://ebiomedia.com/prod/cyclops/images/image004.jpg

12. Application of Energy
Natural form for sources of Energy
Hydro-Carbon
Nuclear Power
Hydro Power
Alternative Energy
Nanotechnology Approaches for Renewable Energy
Generataion
 Solar Energy
 Wind Energy
 Geothermal steam
 Biomass 12

13. Natural Forming sources of Energy, Application
and effects
We know that, our main energy sources for human Flow chart of Energy sources
activity are fossil and mineral fuels, nuclear and
hydroelectric sources.
They are very harmful to environment because
they cause global warning, ozone layer depletion,
biosphere and geosphere destruction, and
ecological devastation. Around 80 wt% of CO2
emissions in the world are originated by the energy
sector
Changes towards environmental improvements are
becoming more politically acceptable globally,
especially in developed countries. Society is
slowly moving towards seeking more sustainable
production methods, waste minimization, reduced
air pollution from vehicles, distributed energy
generation, conservation of native forests, and
reduction of greenhouse gas emissions. 13
Source Figure: Elena Serrano, et al. 2009

14. Renewable sources of Energy, Application and
effects
Flow chart of Renewable Energy sources Nanotechnology is generating a lot
of attention these days and
therefore building great
expectations in renewable energy
challenges with nano-sciences in
21th century, the governments, and
industry.
For renewable energy are solar,
hydrogen and new generation
batteries and supercapacitors are
described as the most significant
examples of the contributions of
nanotechnology in the energy
Source Figure: Elena Serrano, et al. 2009
sector. 14

15. THANKING YOU FOR A KIND ATTENTION…….
15
Source Figure : Elena Serrano, et al. 2009