463264 Harnessing Disorder in a Novel Nanomaterial for Light Harvesting Applications
A variety of light sensitive structures have been examined in our lab, including elongated ZnO rods in N719 dye, an array of nanoparticle systems, and TiO2 inverse opals. Building on this foundation of fabrication experience, we now seek to explore a quantum dot sensitized solar cell. This novel material consists of ‘ultrasmall’ quantum dots, i.e. sub 2 nm diameters, which exhibit a phenomenon known as fluxionality, stemming from their high degree of disorder. Nearly 90% of the atoms in a QD of this size are on the surface and as a result these surface atoms switch bonds with their neighbors, altering their band gaps at femtosecond intervals. With the design proposed here, this fluxionality property will be used to absorb across the visible spectrum and into UV range as well by using the proximity of the UV-absorbing material to space the band gaps of the quantum dot farther apart. This in turn increases the carrier lifetime and allows for the capture of excited electrons.
Herein we report the behavior of this new quantum dot sensitized cell and compare its efficiency to that of N719 and other dyes commonly used in dye sensitized solar cells. We also note the key differences between the absorption capabilities of this novel structure and other quantum dot structures such as core-shell designs.
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