réflecteur dans le contact arrière

CONT: On réduit l'échauffement de ces photopiles en réalisant un réflecteur dans le contact arrière [...], ce qui favorise aussi la création de porteurs de charge aux longueurs d'onde voisines de celle correspondant au seuil d'absorption intrinsèque, en augmentant leur trajet optique. On obtient le réflecteur par une métallisation à l'aluminium; le contact arrière est constitué d'un dépôt multicouche : Al-Ti-Pd-Ag.

CONT: Another innovation is the back-surface reflector (BSR). Even in photovoltaic devices operating at theoretical maximum efficiency, less than 40% of the light to which it is sensitive is absorbed by the cell and converted to electricity. The rest travels through unabsorbed and becomes a system loss. However, the BSR reflects this light back through the cell for a second pass, which greatly increases the conversion efficiency. Also, the BSR reflects radiation to which the cell is not sensitive. This radiation is called out-of-band radiation, and cannot be converted to electricity with this given material bandgap. By reflecting the out-of-band radiation back through the cell, it passes back out the front to the heat source where it is recycled. (Essentially, it helps keep the heat source hot so less fuel is required.)