Civil Engineering Reference
In-Depth Information
FIGURE 8-1
Photovoltaic effect converts the photon energy into voltage across the p-n junction.
FIGURE 8-2
Basic construction of pv cell with performance enhancing features (current collecting mesh,
anti-reflective coating and cover glass protection).
For collecting the photocur-
rent, the metallic contacts are provided on both sides of the junction to collect
electrical current induced by the impinging photons on one side. Conducting
foil (solder) contact is provided over the bottom (dark) surface and on one
edge of the top (illuminated) surface. Thin conducting mesh on the remain-
ing top surface collects the current and lets the light through. The spacing
of the conducting fibers in the mesh is a matter of compromise between
maximizing the electrical conductance and minimizing the blockage of the
light. In addition to the basic elements, several enhancement features are
also included in the construction. For example, the front face of the cell has
anti-reflective coating to absorb as much light as possible by minimizing the
reflection. The mechanical protection is provided by the coverglass applied
with a transparent adhesive.
Figure 8-2
shows the basic cell construction.
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