A heat engine works between a hot reservoir, Ts and an ambient reservoir Ta, and has a limiting efficiency gCarnot ~ 1 —Ta/Ts- 1.7—3.1 eV represent red, green, and blue parts ofthe visible spectrum. About halfthe energy is in wavelengths longerthan visible, energies less than 1.7 eV. A small portion ofthis lightintensity comes indirectly by […]

The “ZnPc/MPP” organic solar cell depicted in Figure 6.20 exhibited an efficiency of 1.05% when illuminated with AM 1.5 radiation at an intensity of 860W/m2. The measured short-circuit current density was 5.2 mA/cm2. This is an early example of a polymer organic cell. This type of cell was earlier shown in Figure 6.10b. We defer […]

A recent theoretical investigation has concluded that dilute magnetic semiconduc­tors may be useful as photovoltaic materials, having the possibility ofthe Fermi level located in a narrow magnetic band inside a larger gap. The compound AlP:Cr has been investigated, even though it has not apparently been synthesized. The main features of the band structure are shown […]

The cost per watt of product can be reduced by raising the efficiency of the cell. If one doubles the efficiency, then one needs only half as many modules to deliver the same power. Such savings apply both to the ingredients of the cells and, importantly, to the glass plates, frames, wiring between cells and […]

This category is also known as concentrated solar power, CSP, with two main forms, the large central receiver and the parabolic trough system. Large central receiver solar thermal electric power plants are shown in Figure 5.4. Design of the mirrors and their tracking is a feat of engineering. Only in a large system does it […]

The single-junction solar cell wastes a bulk of the energy in the incoming light, as we have seen in detail in Chapter 6. Photons of energy greater than the bandgap lose the excess energy to heat, and photons of energy less than the bandgap go through the cell without absorption. An intuitive solution to the […]

In discussing efficiency, it is useful to separate results on small laboratory junctions and those in panels, arrays of junctions (as available) of size measured in meters rather than centimeters. A summary of the most important solar cells and panel types [108] is given in Table 8.1. From the table one sees that the new […]

The single junction solar cell was described in Chapter 3, before Figure 3.17. The limiting efficiency of a single junction cell is 31% at one sun illumination, but as high as 40.8% with concentrated sunlight. The Si single-crystal solar cell shown in Figure 3.17 is the most common first-generation solar cell. Elaborations on this cell […]