>> ON THE AST 12,
WHAT WE'RE DOING IS
WE'RE LOOKING AT HOW PARTICLES
THAT ARE TWO DIFFERENT SIZES,
BY TWO ORDERS OF
MAGNITUDE DIFFERENT,
WITH VERY DIFFERENT CHARGES
ON THEM, WILL AGGREGATE
AND HOPEFULLY CRYSTALLIZE
IN A MICROGRAVITY ENVIRONMENT.
THE NANOPARTICLE HALOING
REFERS TO THE FACT THAT
WE HAVE SMALL PARTICLES
THAT ARE VERY HIGHLY CHARGED
THAT BASICALLY PROTECT
THE LARGE PARTICLES,
WHICH ARE UNCHARGED.
UH, AND THIS ALLOWS OUR SYSTEM
TO BE MUCH MORE STABILIZED,
UH, AND HAVE
LONG-TERM STABILITY.
EVENTUALLY GRAVITY DOES
WIN OUT ON GROUND,
AND THAT'S WHERE WE GET
THAT DENSIFICATION AND
THAT CRYSTAL STRUCTURE FORMING.
BUT WITH THE NANOPARTICLE
HALOING, THAT ALLOWS US
TO GET A CRYSTAL STRUCTURE
AS JUST OPPOSED TO A HODGE PODGE
OF PARTICLES FALLING
IN WHATEVER ORDER
THEY'RE GONNA FALL IN.
UH, THE SMALL PARTICLE,
IN THIS CASE, IS IMPORTANT
FOR WHAT WE WANT TO DO
TECHNOLOGICALLY, BECAUSE
IT'S THAT SMALL PARTICLE
THAT WE CAN THEN USE
TO ACTUALLY TWEAK THE PROPERTIES
OF THE CRYSTAL, WHETHER THAT BE
TO ALLOW THEM TO ABSORB
CERTAIN WAVELENGTHS OF LIGHT
OR EVEN ALLOW US
TO MAYBE REFLECT
OR DEFLECT LIGHT
IN DIFFERENT DIRECTIONS.
WITH OPTICAL COMPUTING,
ONE OF THE KEY ISSUES
THAT YOU RUN INTO IS YOU HAVE TO
BE ABLE TO SWITCH LIGHT.
UH, WHETHER THAT BE
YOU'RE SWITCHING LIGHT FROM
ONE FIBER OPTIC TO ANOTHER
OR EVEN IF YOU'RE TRYING
TO PLAY WITH BITS,
UH, IF YOU HAVE JUST
A SINGLE CRYSTAL MATERIAL,
YOU HAVE NO WAY OF SWTICHING.
BY ADDING IN THAT SECOND
PARTICLE, THOUGH,
THAT'S WHAT ACTUALLY GIVES YOU
THE CAPABILITY OF NOW BEING ABLE
TO DO THINGS LIKE DIFFRACT LIGHT
THROUGH THE CRYSTAL
SO YOU CAN ACTUALLY
GET LIGHT BENDING.
OR BEING ABLE TO SEGMENT LIGHT
SO THAT YOU CAN MAYBE TUNE IT
SO YOU CAN GET
YOUR 1-0 TYPE BITS.
THE MICROGRAVITY ENVIRONMENT
IS IMPORTANT BECAUSE
WHEN WE LOOK AT THESE TYPES
OF SYSTEMS AGGREGATING
IN A GRAVITY ENVIRONMENT,
WHAT TENDS TO HAPPEN IS
THE LARGER PARTICLES WILL
ARTIFICIALLY DENSIFY AS
THEY DROP TO WHATEVER BASE
YOU HAVE AND PUSH OUT
THE SMALL PARTICLES.
SO WHEN I DO GET
A CRYSTAL TO FINALLY FORM,
I'M ONLY GETTING
A CRYSTAL STRUCTURE
OF THAT LARGE PARTICLE.
THE SMALL PARTICLES
TEND TO STAY IN SUSPENSION.
OVER THE LAST COUPLE OF YEARS,
PEOPLE HAVE STARTED
LOOKING AT ORIGINALLY
DYE-SENSITIZED SOLAR CELLS,
AND NOW THEY'VE MOVED INTO
QUANTUM DOT-SENSITIZED
SOLAR CELLS.
AND ONE OF THE MAJOR ISSUES
THAT YOU HAVE WITH
THESE TYPES OF SOLAR CELLS IS
THEY WILL BLEND
A CHARGE-CARRYING PARTICLE,
WHICH IS USUALLY SOMETHING
LIKE TITANIUM OR TIN OXIDE,
WITH A QUANTUM DOT MATERIAL
THAT COULD BE CADMIUM SELENIDE,
LEAD SULFITE,
SOMETHING OF THOSE NATURES.
WHEN THEY DO THIS,
THEY JUST KIND OF MIX THEM AND
THEN THEY PUT THEM ON A SURFACE
AND HOPEFULLY THEY GET SOMETHING
THAT RESEMBLES A NICE STRUCTURE.
BUT BECAUSE THEY'RE NOT
PRE-PLANNING THIS,
THE STRUCTURE THAT
THEY ULTIMATELY END UP WITH
IS SOMEWHAT HAPHAZARD,
WHICH LEADS TO A LOT OF
INEFFICIENCIES WITHIN
THE SOLAR CELL ITSELF.
WHAT WE'RE HOPING TO DO
IS UTILIZE THE NANOPARTICLE
HALOING MECHANISM TO CREATE
A NICE STRUCTURE OF
THE NANOPARTICLES AROUND
OUR CHARGE-CARRYING PARTICLES,
AND THEN WE CRYSTALLIZE
BOTH OF THOSE TOGETHER.
SO NOW YOU HAVE
A CRYSTAL STRUCTURE WITHIN
A CRYSTAL STRUCTURE IN A SENSE,
WHICH THEN ALLOWS YOU
TO PRODUCE CHARGE
MUCH MORE EFFICIENTLY,
HOPEFULLY GIVING US
AS EFFICIENT OF SOLAR CELLS
WE CAN POSSIBLY GET.
THE ADVANTAGE THAT WE GET
WITH USING MAYBE
A QUANTUM DOT-SENSITIZED
SOLAR CELL IS THAT
THEY'RE MUCH CHEAPER TO PRODUCE,
BECAUSE YOU'RE USING
MUCH CHEAPER MATERIALS.
AND, ADDITIONALLY,
IF YOU CAN USE
A POLYMER ELECTROLYTE,
YOU CAN ACTUALLY GET THEM
TO THE POINT WHERE YOU CAN
ROLL THEM UP AND SHIP THEM
AS A ROLL AS OPPOSED
TO HAVING TO SHIP THEM
AS AN ENTIRE PANEL, UH,
SAVING A WHOLE LOT OF SPACE
AS YOU GO UP INTO SPACE.
AT THIS MOMENT,
WE'RE NOT SENDING UP
THE-THE TRUE QUANTUM
DOT-SENSITIZED SOLAR CELL
SYSTEM, PARTIALLY BECAUSE
IT'S A LITTLE BIT
MORE DIFFICULT TO GENERATE.
SO WHAT WE'RE STARTING WITH
IS SORT OF AN ANALOG SYSTEM
WHERE WE'RE USING
A LARGE PARTICLE THAT IS
VERY LIKE SILICA
AND A SMALLER PARTICLE,
WHICH IS READILY AVAILABLE
IN ZIRCONIA.
UH, THESE PARTICLES
ARE VERY EASY TO MODIFY,
THEY'RE VERY EASY TO DEAL WITH,
AND SOLUTION PHASES
WE DON'T NEED TO GO TO HIGH PHs
OR VERY LOW PHs.
UH, THEY'RE VERY EASY
TO SUSPEND WITHIN
AN AQUEOUS SYSTEM, UH,
AND SO THIS ALLOWS US
TO REALLY LOOK AT
THE FUNDAMENTALS OF
NANOPARTICLE HALOING
AND HOW THAT CRYSTALLIZATION
CAN OCCUR, SO THEN WE CAN THEN
TRANSFER THAT KNOWLEDGE
TO THE ACTUAL QUANTUM
DOT-BASED SYSTEMS.
ONE OF THE SYSTEMS THAT
WE HAVE AT THE UNIVERSITY
OF LOUISVILLE IS A ROLL-TO-ROLL
PRINTING TECHNOLOGY, UH,
WHERE WE TAKE FILMS OF POLYMER
AND WE CAN PRINT DIRECTLY
ON THOSE POLYMER FILMS.
AND THIS IS BASICALLY
THE HALF-STEP TO FULL-ON
PRODUCTION CAPABILITY
THAT YOU WOULD SEE
IN ANY INDUSTRY THAT
YOU'RE KIND OF WORKING WITH.
AND THEN YOU'LL BE ABLE
TO ROLL IT UP BECAUSE, AGAIN,
IT IS A ROLL-TO-ROLL PRINTING,
SO YOU'D ACTUALLY ROLL IT UP
AT THE BACK END
AND YOU'D HAVE A ROLLED UP
SOLAR CELL THAT YOU COULD
THEN SELL AS PRODUCT.
NASA GLENN RESEARCH CENTER,
UH, HAS BEEN KEY THROUGHOUT
THIS ENTIRE PROCESS, BECAUSE
WHILE WE HAVE A GENERAL IDEA
OF THE EXPERIMENTS
WE WANT TO PERFORM,
HOW THEY NEED TO BE
PERFORMED IN SPACE
AND WHAT THE ACTUAL
EXPERIMENTAL CONSTRAINTS ARE
ARE SOMETHING THAT
YOU REALLY CAN'T PLAN FOR
UNTIL YOU ACTUALLY COME
AND TALK TO THE PEOPLE HERE.
IN ADDITION, YOU'RE REALLY
LOOKING AT HOW YOU CAN EXTEND
THE SCIENCE BEYOND
WHAT YOU'VE ORIGINALLY
PLANNED FOR,
AND THAT'S REALLY KEY
BECAUSE THE PEOPLE HERE
KNOW WHAT'S GOING ON
ON THE SPACE STATION,
THEY KNOW WHAT THE INSTRUMENTS
ARE CAPABLE OF,
AND THEY KNOW HOW THEY
CAN PUSH THE INSTRUMENTS
INTO NEW DIRECTIONS,
AND THAT'S BEEN
REALLY KEY FOR US.