Nanotechnology in the High School Science Curriculum

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Nanotechnology in the High School Science
Curriculum

• UCF- Science Instructional Analysis
• October 5, 2004

• Kenneth Bowles- NBCT
• Apopka High School

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What Is All the Fuss About Nanotechnology?

• Any given search engine will produce 1.6 million
  hits

Nanotechnology is on the way to becoming the
FIRST trillion dollar market
Nanotechnology influences almost every facet of
every day life such as security and medicine.
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Does Nanotechnology Address Teaching Standards?

• Physical science content standards 9-12
• Structure of atoms
• Structure and properties of matter
• Chemical reactions
• Motion and forces
• Conservation of energy and increase in disorder
  (entropy)
• Interactions of energy and matter

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Does Nanotechnology Address Teaching Standards?

• Science and technology standards
• Abilities of technological design
• Understanding about science and technology
• Science in personal and social perspectives
• Personal and community health
• Population growth
• Natural resources
• Environmental quality
• Natural and human-induced hazards
• Science and technology in local, national, and
  global challenges

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Does Nanotechnology Address Teaching Standards?

• History and nature of science standards
• Science as a human endeavor
• Nature of scientific knowledge
• Historical perspective

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Does Nanotechnology Address Teaching Standards?
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Does Nanotechnology Address Teaching Standards?
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Energy Capture and Storage
Ever consider how much sunlight actually strikes
the earth?
On average every square yard of land exposed to
the sun will receive 5 kW-hours of solar energy
per day. So if you had an area covering 100
square yards you would generate 500 kW-hours per
day.
Upon careful inspection of our energy bill we
discover that the average U.S. household
generates 500-1000 kW-hours of electrical energy
in ONE MONTH. So if we could efficiently harness
the suns energy there could be limitless energy
for us to use.
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Ubiquitous?
Alan Heeger, 2000 Nobel Prize winner in chemistry
for the materials used in PDA screens. These
materials conduct electricity and emit light.
It was discovered that these SAME materials could
absorb light and emit electricity
Goal inexpensive solar cells EVERYWHERE!
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It Is All About the Benjamins!

• Silicon is a costly semi-conductor
• Silicon is bulky
• Silicon is inflexible
• THREE time more expensive than fuel currently
  used on the power grid.
• Costs, due to scale, are going down by 7 per
  year, which is TOO slow.

More people have lost money in bets against
silicon than I know,-Arno Penzias ( Nobel Prize
winner in Physics) But then youre talking a
HUGE possible payback The power market is about
1 trillion.
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We Think It IS Achievable!
Goal To capture 10 of the incoming solar energy.
Plan To develop, using nanoparticles such as
titanium dioxide, solar cells which are made from
cheap plastics. These plastics are very flexible.
The solar cell can even be printed out using an
ink jet printer onto the plastic and rolled up
during manufacturing.
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Applications of Thin Film Solar Cells
Manufacturing will come first, but then???
The idea is that these solar cells can be taken
EVERYWHERE to supply a steady amount of
electricity, reducing the need to PLUG IN for
power.
Eventually, we believe these materials might be
able to be sprayed onto business tiles, vehicles,
and billboards, and then wired up to electrodes.
It might even be possible to eventually feed into
the electric power grid.
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An Example of a Nanotechnology Experiment, Which
Addresses the Standards Constructing
Nanocrystalline Solar Cells Using the Dye
Extracted From Citrus

• Four main parts
• Nanolayer
• Dye
• Electrolyte
• 2 electrodes

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Nanocrystalline Solar Cells

• Main component Fluorine doped tin oxide
  conductive glass slides

Test the slide with a multimeter to determine
which side is conductive
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Synthesis of the Nanotitanium Suspension

• Procedure
• Add 9 ml (in 1 ml increments) of nitric or acetic
  acid (ph3-4) to six grams of titanium dioxide in
  a mortar and pestle.
• Grinding for 30 minutes will produce a lump free
  paste.
• 1 drop of a surfactant is then added ( triton X
  100 or dish washing detergent).
• Suspension is then stored and allow to
  equilibrate for 15 minutes.

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Coating the Cell

• After testing to determine which side is
  conductive, one of the glass slides is then
  masked off 1-2 mm on THREE sides with masking
  tape. This is to form a mold.
• A couple of drops if the titanium dioxide
  suspension is then added and distributed across
  the area of the mold with a glass rod.
• The slide is then set aside to dry for one minute.

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Calcination of the Solar Cells

• After the first slide has dried the tape can be
  removed.
• The titanium dioxide layer needs to be heat
  sintered and this can be done by using a hot air
  gun that can reach a temperature of at least 450
  degrees Celsius.
• This heating process should last 30 minutes.

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Dye Preparation

• Crush 5-6 fresh berries in a mortar and pestle
  with 2-ml of de-ionized water.
• The dye is then filter through tissue or a coffee
  filter and collected.
• As an optional method, the dye can be purified by
  crushing only 2-3 berries and adding 10-ml of
  methanol/acetic acid/water (25421 by volume)

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Dye Absorption and Coating the Counter Electrode

• Allow the heat sintered slide to cool to room
  temperature.
• Once the slide has cooled, place the slide face
  down in the filtered dye and allow the dye to be
  absorbed for 5 or more minutes.

• While the first slide is soaking, determine which
  side of the second slide is conducting.
• Place the second slide over an open flame and
  move back and forth.
• This will coat the second slide with a carbon
  catalyst layer

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Assembling the Solar Cell

• After the first slide had absorbed the dye, it is
  quickly rinsed with ethanol to remove any water.
  It is then blotted dry with tissue paper.
• Quickly, the two slides are placed in an offset
  manner together so that the layers are touching.
• Binder clips can be used to keep the two slides
  together.

• One drop of a liquid iodide/iodine solution is
  then added between the slides. Capillary action
  will stain the entire inside of the slides

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How Does All This Work?

• The dye absorbs light and transfers excited
  electrons to the TiO2.
• The electron is quickly replaced by the
  electrolyte added.
• The electrolyte in turns obtains an electron from
  the catalyst coated counter electrode.

TiO2electron acceptor Iodide electron
donor Dye photochemical pump
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Classroom Ideas For Biology

• Re-creating photosynthesis
• Studying nature can gives us clues as to the
  nature of self-assembly
• Analyzing the potential using different types of
  citrus

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Classroom Ideas for Chemistry

• Solution chemistry making the electrolyte(concentr
  ation is important)
• Chemical reaction involving titanium dioxide
• Oxidation/Reduction Reactions
• Voltaic Cells

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Classroom Ideas for Physics

• Ohms Law
• Internal Resistance
• Cells in Series or parallel
• Measuring current/power density
• Storing solar energy using a capacitor
• Conservation of Energy

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Inquiry Based Learning ModelLet the Kids Play
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Inquiry Examples

• Does the potential change when sunlight is
  filtered using color films?
• Will mixing citrus dyes change the electric
  potential?
• Will aligning the grains of the titanium dioxide
  during drying improve the gain in potential?
• Will cells in series produce a larger voltage?

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For More Information

• Please visit
• www.bowlesphysics.com
• Download this presentation
• Download Teaching Modules