Solar energy harvesting

Finally, the concept of depletion times, as it is used in the construction of the sustainability parameter, is also suitable to include the sustainability of production of facilities needed to harvest resources. For instance, solar energy may in principle have a depletion time of billions of years, but the production of photovoltaic cells usually requires some very scarce elements for which the depletion times are much smaller. The sustainability of using solar energy harvested with photovoltaic cells should then be based on these latter depletion times and not on the depletion time of solar energy itself. 

The input chemicals are carbon dioxide and water, while the output is oxygen and carbohydrates. The latter serve as a feedstock for other organic products such as wood, coal, oil, and gas constituting the World s fossil fuel reserves. It is estimated that about lO tons of carbon dioxide are assimilated annually by plants on Earth, whereby the amount of solar energy harvested by natural photosynthesis is 3 x 10 kJ, corresponding to the continuous generation of 90000 GW of electrical power. 

Volume 9 is concerned with actual and potential applications of metal coordination complexes. Major developments since the 1980s in the uses of coordination compounds have occurred in catalysis and medicine. There have been important developments of coordination chemistry in the technology of dyes and optical materials, for solar energy harvesting, for hydrometallurgical extraction, and in providing MOCVD precursors for new electronic materials. As mentioned above, the last volume in the series contains the indexes. 

On the other hand, single-wall CNTs (SWCNTs) can efficiently absorb and convert photon energy into thermal energy and have excellent thermal conductivities. Thus, they can act as a nanoscale heat source and thermal conduction pathway to heat the crosslinked LCP matrix effectively [51]. Furthermore, the resultant crosslinked PLCP/SWCNT nanocomposites exhibited effective photoactuation not only by white light but by near-IR irradiation as well [52]. Such nanocomposites were used to direct sun-driven artificial heliotropism for solar energy harvesting [53]. 

Li, C. Liu, Y. Huang, X. Jiang, H. Direct sun-driven artificial heliotropism for solar energy harvesting based on a photo-thermomechanical hquid-crystal elastomer nanocomposite. Funct. Mater. 2012. D01 10.1002/adfm.201202038... 

TABLE II Total Annual Amount of Solar Energy Harvested in the Form of Agricultural and Forest Biomass in the U.S. 

---