Sources photovoltaic cells

Since the first photovoltaic (PV) cells were fabricated for the U.S. space program in 1958, PV technology has evolved from once being a very high cost but essential and effective space power source to later becoming a small but diversified and enduring worldwide industry (1 6). Led by firms based in the United States, Japan, and Germany, this industry serves multiple markets (see Photovoltaic cells). 

Action of Vacuum on Spacecraft Materials. For service beyond the atmosphere, the vacuum environment allows materials to evaporate or decompose under the action of various forces encountered (1,18,19). These forces include the photons from the sun, charged particles from solar wind, and dust. The action of space environment on materials and spacecraft can be simulated by a source—sink relationship in a vacuum environment. Thus, for example, the lifetime of a solar panel in space operation may be tested (see Photovoltaic cells). 

The colors of the cylinders represent the modern sources of energy oil (black), natural gas (yellow), wind and water (blue) and solar energy (white). Each cylinder consists of 22 movable circular plates around a central stainless steel column. At daylight, the cylinders begin to move up and down and produce energy by means of photovoltaic cells and a hydraulic system at night they rest. 

Buckley used the same technique to deposit films for photovoltaic cells [113], only with CdCli as Cd source and apparently a lower Cd concentration. Electron diffraction of these films showed a predominantly zincblende structure with some wurtzite phase. The films were p-type with a resistivity of 20 5 fl-cm. These values, and the subsequent photovoltaic cells, apparently refer to as-deposited films no reference to annealing was made in this stndy. 

The electrons would not travel to the negatively charged silicon on their own. They can, however, be forced to move in this direction given an adequate energy source. Fora photovoltaic cell, this energy source is sunlight, which literally knocks electrons towards this direction. 

PHOTOVOLTAIC CELLS. A photovoltaic (PV) solar power system is a complete electrical source that uses solar cells to directly convert light enetgy into electricity The system can he self-contained and. completely autonomous or it can work in tandem with other conventional fuel-based sources of power to offer robust power availability. 

The brute force approach to achieve this goal is to employ a solid-state photovoltaic cell to generate electricity that is subsequently passed into a commercial-type water electrolyzer. Although efficiencies obtained are relatively high, i.e., close to 8 %, these devices are very expensive. Hence the price of hydrogen produced this way cannot compete with conventional sources. The long-term outlook is better for systems that borrow their principles from natural photosynthesis (see Section 1.4.1 above). 

---