Photovoltaics principles

Solar Engineering Research Institute. Basic Photovoltaic Principles and Methods (FT-290-1448). Washington, D.C. U.S. Government Printing Office, 1982. 

For reviews of photovoltaic principles and applications, consult Merrigan, J.A., "Sunlight to Electricity - Prospects for Solar Energy Conversion by Photovoltaics", MIT Press, Cambridge, Mass., 1975 "Solar Cells", C.E. Backus, ed.,... 

A photovoltaic material generates a voltage when it is exposed to light and photovoltaic can be considered as a specialized area of optoelectronics. The principle has been known for many decades but it became a industrial reality only in 1958 when an array of photovoltaic cells, based on single-crystal silicon, provided power for a space vehicle. 

These significant findings form the basis of a set of design principles for the construction of molecular photovoltaic cells and other nanoscale electronic devices in which the control of both the rate and directionality of ET processes is an essential requirement. The successful construction of an artificial light-driven proton pump, based on principles of long-range ET processes illustrates the promise of this approach.1501... 

If hydrogen is produced via solar photovoltaic (PV)-powered water electrolysis, it would be possible, in principle, to provide energy on a global scale, with essentially no greenhouse gas emission and veiy low local pollution. 

Gerischer H (1981) The principles of photoelectrochemical energy conversion. In Cardon F, Gomes WP, Dekeyser W (Eds) Photovoltaic and photoelectrochemical solar energy conversion. Plenum, New York, pp. 199-245... 

Materials with large E ex values would not be indicated for e.g., photovoltaic devices, since the photogeneration of charge carriers would be inefficient, but could in principle be used as light emitting diodes. Section 4.2 will show examples of the experimental determination of the band diagrams of selected organic semiconductors. El is usually obtained from o vs. T measurements, since a oc ... 

There are another type of photocells known as barrier layer photocells which work on an entirely different principle. They are semiconductor devices in which impinging photons promote the electrons from the valence band to the conduction band across the energy gap. A photovoltagc is generated which can be measured by a voltmeter. Such photovoltaic devices can have a large surface area and are easy to operate. They are commonly used in many simple colorimeters and fluorimeters and as light Otters for cameras. 

Photovoltaic Electrolysis Cells. These cells produce both fuel (e.g. H2) and electrical power by means of a low-energy electrochemical reaction such as the dissociation of HI. The principle of this cell is shown in Figure 6.27. 

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. 

After the introduction, we will briefly discuss the main characteristics of solar radiation. Consistent with the scientific principles on which this book is founded, a rigorous thermodynamic analysis will then follow of the creation of wind energy, of photothermal and photovoltaic energy conversion, and of photosynthesis. Most of this chapter has been based on the monograph Thermodynamics of Solar Energy Conversion by De Vos [1]. 

On principle, renewable energies are without operational primary energy raw materials per se, their conversion technologies are one and all - such as the wind energy converter, the photovoltaic cell, the hydro turbine, the heat pump, the biomass converter, or the solar-thermal power station. 

M.A. Green, Silicon Solar Cells - Advanced Principles Practice (Centre for Photovoltaic Devices and Systems, Sydney, 1995)... 

Photovoltaic cells. As the name suggests, these involve direct conversion of light into electric current. The reaction at the auxiliary electrode is the inverse of that at the semiconductor electrode. In principle, there is no change in electrolyte composition with time. An example would be... 

A. Rothwarf, The superposition principle for currents in solar cells, in Proc. 13th Photovoltaic Specialists Conf., 1978, pp. 1312-1317. 

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