Solar energy conversion efficiency

Both direct and indirect biophotolysis routes suffer from a number of challenges that currently prohibit them from becoming commercially viable processes [180] these include, but are not limited to, solar energy conversion efficiency and the difficulty of bioreactor design. In particular the low solar energy to hydrogen conversion efficiency is a matter of major concern in the field of biophotolysis. The efficiency is calculated as [180,172] ... 

High solar-energy conversion efficiency. A high efficiency equal to that of the amorphous Si solar cell has been obtained as a laboratory development and efficiencies greater than 10% might be possible. 

Figure 3. Plot showing the variation of solar energy conversion efficiency with threshold wavelengths at sea level. The solid vertical lines represent the energies required for decomposition of water using one or two photons per molecule of water respectively (4 photons would be at 2000 nm). The dashed vertical lines represent computed values for these threshold wavelengths taking into account unavoidable thermodynamic losses (adapted from ref. 8)...

Improved Solar Energy Conversion Efficiencies for the Photocatalytic Production of Hydrogen via TiCte Semiconductor Electrodes Heat treatment of Ti metal found to influence performance. 234... 

Several attempts have been made to analyse the limits of solar energy conversion efficiency. Calculations have been made for quantum "" and thermal systems, but nothing new has been reported. Similarly, the factors affecting the efficiency of photochemical water cleavage systems have been considered Unfortunately, the endpoint of such calculations has not resulted in improvements to existing systems or development of new approaches. 

A practical disadvantage of the sensitized planar electrodes described in the previous section was their low solar energy conversion efficiencies. An experimental drawback was that characterization was limited to photoelectrochemical or luminescence techniques. Both of these issues arose from the poor light harvesting by monolayers on flat surfaces or inefficient interfacial electron transfer yields from thick films or concentrated solutions. In 1990, Gratzel and co-workers reported experimental studies of dye sensitized colloidal Ti02 films that eliminated both of these problematic issues [112]. The effective surface area for sensitizer binding... 

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