good morning it has been a truly exciting week for me it’s a very
exciting week for me it’s a very
exciting week for me it’s a very empowering experience for me to get to
empowering experience for me to get to
empowering experience for me to get to know my fellow emerging explorers for me
know my fellow emerging explorers for me
know my fellow emerging explorers for me I’m passionate about energy problems I
I’m passionate about energy problems I
I’m passionate about energy problems I hope we can have a sustainable energy
hope we can have a sustainable energy
hope we can have a sustainable energy future so growing up in China in the
future so growing up in China in the
future so growing up in China in the period that the Cultural Revolution was
period that the Cultural Revolution was
period that the Cultural Revolution was in the past
in the past
in the past China has opened up its doors to look
China has opened up its doors to look
China has opened up its doors to look for better economy and better lives our
for better economy and better lives our
for better economy and better lives our lives are getting better and the better
lives are getting better and the better
lives are getting better and the better but energy is always scarce
but energy is always scarce
but energy is always scarce I remember used to watch my mom working
I remember used to watch my mom working
I remember used to watch my mom working in the kitchen under very dim light try
in the kitchen under very dim light try
in the kitchen under very dim light try to save electricity
to save electricity
to save electricity about 10 years ago my parents bought a
about 10 years ago my parents bought a
about 10 years ago my parents bought a solar thermal systems like many city
solar thermal systems like many city
solar thermal systems like many city people they live in apartments those
people they live in apartments those
people they live in apartments those high-rise buildings so they install the
high-rise buildings so they install the
high-rise buildings so they install the solar system on the rooftop of their
solar system on the rooftop of their
solar system on the rooftop of their buildings so such a system will heat up
buildings so such a system will heat up
buildings so such a system will heat up their domestic water so they can have
their domestic water so they can have
their domestic water so they can have access to hot water and that makes a
access to hot water and that makes a
access to hot water and that makes a huge difference for their life quality
huge difference for their life quality
huge difference for their life quality and like many families they want to
and like many families they want to
and like many families they want to install such systems on the rooftop and
install such systems on the rooftop and
install such systems on the rooftop and then becomes a competition everyone
then becomes a competition everyone
then becomes a competition everyone everyone wants a space there so one day
everyone wants a space there so one day
everyone wants a space there so one day my father said it will be really nice we
my father said it will be really nice we
my father said it will be really nice we can hang a solar thermal panels outside
can hang a solar thermal panels outside
can hang a solar thermal panels outside our window the piping will be simpler
our window the piping will be simpler
our window the piping will be simpler and everyone will have access to the
and everyone will have access to the
and everyone will have access to the renewable energy so that makes me think
renewable energy so that makes me think
renewable energy so that makes me think about there really a strong need for
about there really a strong need for
about there really a strong need for this kind of flexible and lightweight
this kind of flexible and lightweight
this kind of flexible and lightweight solar systems that motivates me to
solar systems that motivates me to
solar systems that motivates me to develop later on the solar cell stickers
develop later on the solar cell stickers
develop later on the solar cell stickers and this work is done by my students and
and this work is done by my students and
and this work is done by my students and me as temporary University so the solar
me as temporary University so the solar
me as temporary University so the solar stickers are like downside just like the
stickers are like downside just like the
stickers are like downside just like the stickers your kids put on your clothes
stickers your kids put on your clothes
stickers your kids put on your clothes to say thank you mom good job mom
to say thank you mom good job mom
to say thank you mom good job mom you peel them off and then stick it to
you peel them off and then stick it to
you peel them off and then stick it to anywhere you want so that we can
anywhere you want so that we can
anywhere you want so that we can increase the places we can use solar
increase the places we can use solar
increase the places we can use solar energy the reason I’m interested in
energy the reason I’m interested in
energy the reason I’m interested in solar energy is very simple there is
solar energy is very simple there is
solar energy is very simple there is abundant resources of solar energy so
abundant resources of solar energy so
abundant resources of solar energy so here shows the world’s energy resources
here shows the world’s energy resources
here shows the world’s energy resources the big one in the center is the annual
the big one in the center is the annual
the big one in the center is the annual energy from the Sun and the one on the
energy from the Sun and the one on the
energy from the Sun and the one on the right hand side are from the finite
right hand side are from the finite
right hand side are from the finite resources for example the petroleum coal
resources for example the petroleum coal
resources for example the petroleum coal natural gas etc and the small circles in
natural gas etc and the small circles in
natural gas etc and the small circles in the center represent those renewable
the center represent those renewable
the center represent those renewable sources their annual energy output for
sources their annual energy output for
sources their annual energy output for example wind geothermal etc the tool
example wind geothermal etc the tool
example wind geothermal etc the tool pollute us on a very left hand side
pollute us on a very left hand side
pollute us on a very left hand side represent our annual consumption of
represent our annual consumption of
represent our annual consumption of energy the smaller one is about energy
energy the smaller one is about energy
energy the smaller one is about energy consumption in 2010 the bigger one is
consumption in 2010 the bigger one is
consumption in 2010 the bigger one is the estimated energy consumption in 2050
the estimated energy consumption in 2050
the estimated energy consumption in 2050 so you can see our energy consumption is
so you can see our energy consumption is
so you can see our energy consumption is increasing as we want to preserve our
increasing as we want to preserve our
increasing as we want to preserve our energy our lifestyle and people from
energy our lifestyle and people from
energy our lifestyle and people from developing countries are looking for
developing countries are looking for
developing countries are looking for better life quality but if we continue
better life quality but if we continue
better life quality but if we continue to rely on fossil fuels we’re going to
to rely on fossil fuels we’re going to
to rely on fossil fuels we’re going to deplete them one day sooner or later
deplete them one day sooner or later
deplete them one day sooner or later because we’re using them simply at a
because we’re using them simply at a
because we’re using them simply at a rate much faster they can be regenerated
rate much faster they can be regenerated
rate much faster they can be regenerated we have to rely more and more on
we have to rely more and more on
we have to rely more and more on renewable energy and solar is a
renewable energy and solar is a
renewable energy and solar is a wonderful resource we are using solar
wonderful resource we are using solar
wonderful resource we are using solar energy now we’re using them in the forms
energy now we’re using them in the forms
energy now we’re using them in the forms of solar panels you probably all have
of solar panels you probably all have
of solar panels you probably all have seen this kind of flat panel looking
seen this kind of flat panel looking
seen this kind of flat panel looking thing dark color facing the Sun so those
thing dark color facing the Sun so those
thing dark color facing the Sun so those solar panels essentially is a Sun
solar panels essentially is a Sun
solar panels essentially is a Sun powered battery when the Sun illuminates
powered battery when the Sun illuminates
powered battery when the Sun illuminates those solar panels they will generate
those solar panels they will generate
those solar panels they will generate electron holes the flow of electrons and
electron holes the flow of electrons and
electron holes the flow of electrons and holes will generate current and that
holes will generate current and that
holes will generate current and that current powers the electrical load for
current powers the electrical load for
current powers the electrical load for example your phone’s a lamp etc so you
example your phone’s a lamp etc so you
example your phone’s a lamp etc so you can think about solar cell is a Sun
can think about solar cell is a Sun
can think about solar cell is a Sun power the battery comes in charged by
power the battery comes in charged by
power the battery comes in charged by sunlight
sunlight
sunlight if we look a little deeper into these
if we look a little deeper into these
if we look a little deeper into these solar cells solar cells just like a
solar cells solar cells just like a
solar cells solar cells just like a battery as I mentioned as all batteries
battery as I mentioned as all batteries
battery as I mentioned as all batteries you will have a positive and a negative
you will have a positive and a negative
you will have a positive and a negative side so the grayish color on the top and
side so the grayish color on the top and
side so the grayish color on the top and the bottom are the positive and active
the bottom are the positive and active
the bottom are the positive and active part there are metallic layers and
part there are metallic layers and
part there are metallic layers and what’s in between is semiconductor
what’s in between is semiconductor
what’s in between is semiconductor frequently silicon that can absorb
frequently silicon that can absorb
frequently silicon that can absorb sunlight and generate electrons and
sunlight and generate electrons and
sunlight and generate electrons and holes that drive the current so you can
holes that drive the current so you can
holes that drive the current so you can think about from the structure
think about from the structure
think about from the structure perspective this solar cell looks like a
perspective this solar cell looks like a
perspective this solar cell looks like a sandwich right it’s the semiconductor
sandwich right it’s the semiconductor
sandwich right it’s the semiconductor sandwiched between two electrons if this
sandwiched between two electrons if this
sandwiched between two electrons if this whole thing is a sin as one type of
whole thing is a sin as one type of
whole thing is a sin as one type of solar cell called the symptom solar
solar cell called the symptom solar
solar cell called the symptom solar cells then it has the potential to
cells then it has the potential to
cells then it has the potential to become flexible and and lightweight if
become flexible and and lightweight if
become flexible and and lightweight if we look at the key parameters we
we look at the key parameters we
we look at the key parameters we characterize solar cell the one
characterize solar cell the one
characterize solar cell the one parameter is called
parameter is called
parameter is called efficiency that’s how much power can be
efficiency that’s how much power can be
efficiency that’s how much power can be generated compared to how much power is
generated compared to how much power is
generated compared to how much power is incident by sunlight in other words is
incident by sunlight in other words is
incident by sunlight in other words is how much what percentage of Sun power
how much what percentage of Sun power
how much what percentage of Sun power you can convert it to electricity for
you can convert it to electricity for
you can convert it to electricity for most solar cells in the market is about
most solar cells in the market is about
most solar cells in the market is about 10 to 20 percent for example if we have
10 to 20 percent for example if we have
10 to 20 percent for example if we have a 15 percent solar panels if you have
a 15 percent solar panels if you have
a 15 percent solar panels if you have one square centimeter area you can
one square centimeter area you can
one square centimeter area you can generate about 150 watt that’s enough to
generate about 150 watt that’s enough to
generate about 150 watt that’s enough to power two to three lumps if I have a
power two to three lumps if I have a
power two to three lumps if I have a rock the size of this rock if you
rock the size of this rock if you
rock the size of this rock if you probably roughly generate about 500 watt
probably roughly generate about 500 watt
probably roughly generate about 500 watt that’s the magnitude so to increase the
that’s the magnitude so to increase the
that’s the magnitude so to increase the energy production by solar cells one is
energy production by solar cells one is
energy production by solar cells one is to increase efficiency they order to
to increase efficiency they order to
to increase efficiency they order to increase the area you want to use it so
increase the area you want to use it so
increase the area you want to use it so we want to make them to be able to
we want to make them to be able to
we want to make them to be able to applied not only rooftops for example
applied not only rooftops for example
applied not only rooftops for example this is the rooftop solar panels at the
this is the rooftop solar panels at the
this is the rooftop solar panels at the Stanford has over the business center
Stanford has over the business center
Stanford has over the business center and those are great for rooftop
and those are great for rooftop
and those are great for rooftop applications but as I mentioned we want
applications but as I mentioned we want
applications but as I mentioned we want to increase the places they’re only
to increase the places they’re only
to increase the places they’re only limited space and rooftops it will be
limited space and rooftops it will be
limited space and rooftops it will be nice we can put on cars or maybe on the
nice we can put on cars or maybe on the
nice we can put on cars or maybe on the sidewall of buildings then those solar
sidewall of buildings then those solar
sidewall of buildings then those solar cells have to be flexible so what’s the
cells have to be flexible so what’s the
cells have to be flexible so what’s the challenge
challenge
challenge this is how Soler’s out look like for
this is how Soler’s out look like for
this is how Soler’s out look like for those symptom solar cells so the bluish
those symptom solar cells so the bluish
those symptom solar cells so the bluish color is the sandwich structure that’s
color is the sandwich structure that’s
color is the sandwich structure that’s the solar cell that’s the active part as
the solar cell that’s the active part as
the solar cell that’s the active part as generate electricity and those things
generate electricity and those things
generate electricity and those things have to be manufactured on a substrate
have to be manufactured on a substrate
have to be manufactured on a substrate the substrate is a holder for them the
the substrate is a holder for them the
the substrate is a holder for them the substrate typically is glass or silicon
substrate typically is glass or silicon
substrate typically is glass or silicon wafer Austin is stills so the solar cell
wafer Austin is stills so the solar cell
wafer Austin is stills so the solar cell part is only a couple microns about one
part is only a couple microns about one
part is only a couple microns about one tenth of the thickness of the plastic
tenth of the thickness of the plastic
tenth of the thickness of the plastic fruit ripe you use that’s very thin very
fruit ripe you use that’s very thin very
fruit ripe you use that’s very thin very flexible but the substrate is about a
flexible but the substrate is about a
flexible but the substrate is about a millimeter scale as about thousand times
millimeter scale as about thousand times
millimeter scale as about thousand times thicker and that’s the part caused the
thicker and that’s the part caused the
thicker and that’s the part caused the solar cells to be heavy to be rigid but
solar cells to be heavy to be rigid but
solar cells to be heavy to be rigid but we need o substrate as a holder to
we need o substrate as a holder to
we need o substrate as a holder to fabricate the material so during the
fabricate the material so during the
fabricate the material so during the fabrication they put the substrate there
fabrication they put the substrate there
fabrication they put the substrate there and the deposited material on top it’s
and the deposited material on top it’s
and the deposited material on top it’s similar as the process as ladies do you
similar as the process as ladies do you
similar as the process as ladies do you make up we have the face as the
make up we have the face as the
make up we have the face as the substrate we put layers in the layers of
substrate we put layers in the layers of
substrate we put layers in the layers of materials and they are very thin so they
materials and they are very thin so they
materials and they are very thin so they don’t show up very much so the idea here
don’t show up very much so the idea here
don’t show up very much so the idea here is if we can replace that rigid
is if we can replace that rigid
is if we can replace that rigid substrate by something flexible for
substrate by something flexible for
substrate by something flexible for example paper or plastic then
example paper or plastic then
example paper or plastic then essentially we can have a flexible
essentially we can have a flexible
essentially we can have a flexible substrate but we cannot directly to
substrate but we cannot directly to
substrate but we cannot directly to stick the paper into the solar cell
stick the paper into the solar cell
stick the paper into the solar cell manufacturers they cannot sustain the
manufacturers they cannot sustain the
manufacturers they cannot sustain the environment the temperature the
environment the temperature the
environment the temperature the chemicals we require to manufacture
chemicals we require to manufacture
chemicals we require to manufacture solar cells right so what we do is the
solar cells right so what we do is the
solar cells right so what we do is the inspiration from food is the PISA
inspiration from food is the PISA
inspiration from food is the PISA approach
approach
approach when we bake the Pisa we put this Pisa
when we bake the Pisa we put this Pisa
when we bake the Pisa we put this Pisa in a ceramic pan the ceramic pan can
in a ceramic pan the ceramic pan can
in a ceramic pan the ceramic pan can sustain the high temperature in your
sustain the high temperature in your
sustain the high temperature in your oven to cook the pizza but we deliver
oven to cook the pizza but we deliver
oven to cook the pizza but we deliver the Pisa which transfer that pizza out
the Pisa which transfer that pizza out
the Pisa which transfer that pizza out put in the paper box that’s much cheaper
put in the paper box that’s much cheaper
put in the paper box that’s much cheaper so we can have people at a very
so we can have people at a very
so we can have people at a very economical price so essentially when we
economical price so essentially when we
economical price so essentially when we look at the Pisa essentially we have a
look at the Pisa essentially we have a
look at the Pisa essentially we have a two carriers for two different functions
two carriers for two different functions
two carriers for two different functions the pan is for the high temperature
the pan is for the high temperature
the pan is for the high temperature manufacturing process and the paper is
manufacturing process and the paper is
manufacturing process and the paper is for the deliver and transportation
for the deliver and transportation
for the deliver and transportation purpose we can do the same thing for
purpose we can do the same thing for
purpose we can do the same thing for solar cells this is how we do it this is
solar cells this is how we do it this is
solar cells this is how we do it this is again this two layer structure so do the
again this two layer structure so do the
again this two layer structure so do the blue is the solar cell and the bottom is
blue is the solar cell and the bottom is
blue is the solar cell and the bottom is the thick glass of silicon wafers what
the thick glass of silicon wafers what
the thick glass of silicon wafers what we do differently is we insert a
we do differently is we insert a
we do differently is we insert a metallic layer in between and that layer
metallic layer in between and that layer
metallic layer in between and that layer serve as a sacrificial layer later on
serve as a sacrificial layer later on
serve as a sacrificial layer later on and the solar cells will be manufactured
and the solar cells will be manufactured
and the solar cells will be manufactured as identical procedures and conditions
as identical procedures and conditions
as identical procedures and conditions as your regulars in film solar cells
as your regulars in film solar cells
as your regulars in film solar cells what we do next is we soak it in water
what we do next is we soak it in water
what we do next is we soak it in water room temperature water just our tap
room temperature water just our tap
room temperature water just our tap water an inside water we just pure it
water an inside water we just pure it
water an inside water we just pure it during this peeling process the metallic
during this peeling process the metallic
during this peeling process the metallic layers separate from the substrate the
layers separate from the substrate the
layers separate from the substrate the class so now we have these thin solar
class so now we have these thin solar
class so now we have these thin solar cell coming out kind of like when ladies
cell coming out kind of like when ladies
cell coming out kind of like when ladies apply the face mask sometimes you paint
apply the face mask sometimes you paint
apply the face mask sometimes you paint it and when you remove it it comes out
it and when you remove it it comes out
it and when you remove it it comes out as an entire layer it’s the same thing
as an entire layer it’s the same thing
as an entire layer it’s the same thing but we have water there now with this
but we have water there now with this
but we have water there now with this thin solar cells as I mentioned only a
thin solar cells as I mentioned only a
thin solar cells as I mentioned only a couple microns is very thin and you can
couple microns is very thin and you can
couple microns is very thin and you can stick it as a sticker to the back of
stick it as a sticker to the back of
stick it as a sticker to the back of your cell phones and that realize the
your cell phones and that realize the
your cell phones and that realize the transfer process so now we have two
transfer process so now we have two
transfer process so now we have two substrate one for fabrication one as the
substrate one for fabrication one as the
substrate one for fabrication one as the carrier when you use it so the magical
carrier when you use it so the magical
carrier when you use it so the magical part to me is really what happens in the
part to me is really what happens in the
part to me is really what happens in the water and that’s where we have work on
water and that’s where we have work on
water and that’s where we have work on so this shows the process in water
so this shows the process in water
so this shows the process in water what we have is a four inch wafer with
what we have is a four inch wafer with
what we have is a four inch wafer with the metallic layer on silicon my
the metallic layer on silicon my
the metallic layer on silicon my students are just working through the
students are just working through the
students are just working through the edges try to make sure the edges are
edges try to make sure the edges are
edges try to make sure the edges are clean you can see in initial 1/2 minute
clean you can see in initial 1/2 minute
clean you can see in initial 1/2 minute he’s just working through the edges and
he’s just working through the edges and
he’s just working through the edges and then we only within a few seconds if you
then we only within a few seconds if you
then we only within a few seconds if you off the entire thing what you see in the
off the entire thing what you see in the
off the entire thing what you see in the front is the silicon wafer that you can
front is the silicon wafer that you can
front is the silicon wafer that you can use for the fabrication of solar cells
use for the fabrication of solar cells
use for the fabrication of solar cells and you can see after this process is
and you can see after this process is
and you can see after this process is very clean to use it again just like the
very clean to use it again just like the
very clean to use it again just like the pans for pizza for solar cell
pans for pizza for solar cell
pans for pizza for solar cell fabrications the one on the back the
fabrications the one on the back the
fabrications the one on the back the shiny part is the metallic metallic
shiny part is the metallic metallic
shiny part is the metallic metallic layer and the solar cells can be behind
layer and the solar cells can be behind
layer and the solar cells can be behind that now you have a solar cell sticker
that now you have a solar cell sticker
that now you have a solar cell sticker you can stick it to anywhere and this
you can stick it to anywhere and this
you can stick it to anywhere and this process only requires water and really
process only requires water and really
process only requires water and really fast you can see this takes less than 2
fast you can see this takes less than 2
fast you can see this takes less than 2 minutes so we collaborated with National
minutes so we collaborated with National
minutes so we collaborated with National Renewable Energy Lab they fabricate is
Renewable Energy Lab they fabricate is
Renewable Energy Lab they fabricate is amorphous silicon solar cells and our
amorphous silicon solar cells and our
amorphous silicon solar cells and our modified silicon wafers and those
modified silicon wafers and those
modified silicon wafers and those circles are the solar cells after this
circles are the solar cells after this
circles are the solar cells after this pure process we attach it to my business
pure process we attach it to my business
pure process we attach it to my business card yeah and it’s very flexible and
card yeah and it’s very flexible and
card yeah and it’s very flexible and this is the initial silicon wafer and
this is the initial silicon wafer and
this is the initial silicon wafer and it’s very clean you can use it again the
it’s very clean you can use it again the
it’s very clean you can use it again the key parameter for solar cell is
key parameter for solar cell is
key parameter for solar cell is efficiency
efficiency
efficiency so after this transfer process the
so after this transfer process the
so after this transfer process the efficiency remains the same that means
efficiency remains the same that means
efficiency remains the same that means the process so gentle it doesn’t damage
the process so gentle it doesn’t damage
the process so gentle it doesn’t damage the solar cell and that’s the key with
the solar cell and that’s the key with
the solar cell and that’s the key with this pew technology we think can really
this pew technology we think can really
this pew technology we think can really go beyond solar cell it really doesn’t
go beyond solar cell it really doesn’t
go beyond solar cell it really doesn’t depend on the solar cell we are just
depend on the solar cell we are just
depend on the solar cell we are just controlling the interface if you replace
controlling the interface if you replace
controlling the interface if you replace the solar cells with some film
the solar cells with some film
the solar cells with some film electronics for example this apply we
electronics for example this apply we
electronics for example this apply we can have flexible displays o batteries
can have flexible displays o batteries
can have flexible displays o batteries we have symptom batteries or sensors
we have symptom batteries or sensors
we have symptom batteries or sensors ultrason sensors to them for human house
ultrason sensors to them for human house
ultrason sensors to them for human house monitoring or environmental monitoring
monitoring or environmental monitoring
monitoring or environmental monitoring or any other symptom electronic devices
or any other symptom electronic devices
or any other symptom electronic devices you can imagine so it’s a very powerful
you can imagine so it’s a very powerful
you can imagine so it’s a very powerful technique for flexible electronics with
technique for flexible electronics with
technique for flexible electronics with this technique I dream I dream one day
this technique I dream I dream one day
this technique I dream I dream one day we can stick those solar cells to the
we can stick those solar cells to the
we can stick those solar cells to the all of the buildings to the shade of
all of the buildings to the shade of
all of the buildings to the shade of your windows to your helmet to the back
your windows to your helmet to the back
your windows to your helmet to the back of your phones your iPad to your
of your phones your iPad to your
of your phones your iPad to your backpack with that we can power the
backpack with that we can power the
backpack with that we can power the world and with that we can contribute to
world and with that we can contribute to
world and with that we can contribute to a sustainable energy future thank you
a sustainable energy future thank you
a sustainable energy future thank you very much
”
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