Past research has discovered a technique for photocatalyst synthesis utilizing never-dried cellulose fiber in order to produce non-agglomerating nanocrystals. This new technique allows the production of semiconductors in a flexible form. This form is useful in many areas, including in spacecraft technology, where solar panels must be kept in a compact form before deployment. One possible catalyst for this is gallium arsenide (GaAs), which holds many traits that are favorable to semiconductor devices in electronics. With a band gap that is receptive to visible light and many industry applications in radio frequency, light sensors and LEDs, gallium arsenide is an attractive candidate for storage in cellulose fiber. In particular, this storage method allows for the synthesis of long strands containing GaAs that are useful in solar cells. In order to form an electrostatic region necessary for electronic applications, a P-N junction must be formed within the compound. This is usually done by heating the compound and injecting ions into the structure so that P-N junctions are naturally formed. However, since the fibers are unable to be heated to the temperatures needed without compromising the storage, we instead propose that a magnetic field can be placed across the semiconductor during formation, with doping ions placed within the fiber so that the junctions naturally form within the GaAs structure. This new method for semiconductor production has the potential to offer a new strategy for electronic production that can exist in a flexible format.

One of the main science goals of the Large Synoptic Survey Telescope (LSST) is to further understand the relationship between dark energy and the universe's expansion. In order to achieve this scientific goal of the LSST, accurate estimates of photometric redshifts, which are used as a proxy for cosmological distance, for galaxies are required. To improve its estimates of photometric redshifts, the LSST could incorporate near-infrared data from other surveys along with its optical measurements of galaxy brightness. In order to understand how photometric redshifts improve with the addition of near-infrared (NIR) data, we statistically compare the quality of photometric redshifts using simulated galaxy catalogs with optical-only and optical-plus-NIR data. In my poster, I quantify the expected improvements to photometric redshifts when LSST optical data is combined with NIR data from the future ESA Euclid or NASA WFIRST space telescopes. In general, WFIRST has less outlier galaxies because WFIRST’s NIR filters have a redder band and can cover deeper in the IR spectrum.

Hydrogen fuel is a non-polluting, sustainable energy source that is a very attractive alternative to fossil fuels. A popular way to obtain this fuel is splitting water with semiconductor photocatalysts, which is inexpensive and efficient. This method relies on sunlight alone to activate the water-splitting photocatalysts. Once the catalysts have absorbed UV light, they begin to split the water molecules that are in contact with their surface. As a result of this, hydrogen fuel is produced more rapidly using a given amount of catalyst when the catalytic crystals have a high surface area to volume ratio, which means the smaller the crystals are, the more efficiently they work. To keep these crystals small, our research group uses a unique method developed by Dr. G. Allan to synthesize and store semiconductor photocatalysts. Instead of synthesizing them normally, we form the crystals inside cellulose fibers. This keeps them from losing surface area to agglomeration. The micropores of cellulose force the catalyst to form as small, insoluble, nanocrystals in a cheaper fashion than traditional methods. We then focused on finding the most effective semiconductor photocatalyst to be stored in fiber. The chosen photocatalyst must have specific properties. It must be synthesizable in an aqueous solution at less than 40 degrees celsius to keep the cellulose pores from collapsing or charring, it must be non-toxic, and it must have a band gap between 1.8eV to 2.7eV in order to absorb visible light. Our project group has spent the last few months researching different materials to determine the most beneficial materials, and we have concluded that the best possible candidates are black titanium oxide, niobium pentoxide, bismuth vanadate, zinc oxide, molybdenum sulfide, and tungsten trioxide. We hope to use these findings to promote an alternative source of clean energy into the market.