Figure 59 Illustration of various size regimes of the kinetics of solid-solid phase
transitions. Defects, which act as nucleation sites, are indicated by asterisks in the
cartoon of the bulk solid.POTENTIAL IMPACT
An R&D investment in basic science and technology targeting solar-related materials is
extremely relevant to the efficiency and cost goals of DOE in the solar area. Although there are
several materials available to make thin-film PV cells today, an ideal material has not yet been
found. Experimental and theoretical screening could discover several direct band-gap
semiconductors that have band-gaps ranging from 0.7 eV to 2.5 eV, function well in PV cells,
and are made from elements abundant in the Earth’s crust. New materials could lead to the
development of devices that enable the achievement of a ~35%-efficient power conversion in
concentrated solar systems. Successful research on new polymer materials can lead to a 15%
efficiency improvement and a factor of two reduction in cost, which would represent a
revolutionary breakthrough in solar thermal electricity and space heating. New effective thermal
storage materials and systems will be a great advance towards dealing with the issues of diurnal
solar energy.
REFERENCES
G. Chen, “Phonon Heat Conduction in Low-Dimensional Structures,” Semicond. & Semimetals
71 , 203–259 (2001).