ABSTRACT
The photovoltaic effect was first discovered by the French scientist Antoine Cesar Becquerel in 1839. This effect was twice described at the Academie des Sciences in Paris by his son Alexandre Edmond [1]. They revealed an intriguing phenomenon corresponding to the generation of a current flowing when setting two platinum plates in contact with an aqueous acidic galvanic cell under illumination. To enable this new physical occurrence, one of the two electrode surfaces was modified beforehand by a halide vapor (iodide, chloride, and bromide). Depending on the experimental procedure
that varies this halide-based layer thickness, they found a photocurrent flowing in one or the other direction, which is the premise of an n-or p-type film depending upon the deposition conditions. For a long time, this starting point of the photovoltaic effect was only considered a scientific curiosity. A mechanistic explanation of this effect was given by A. Einstein in 1905 through his general theory. He earned his first Nobel prize in Physics in 1921 for the explanation of the photoelectric effect. Nobody envisioned at that time that the field of photonics would grow into a new area combining abundant fundamental and applied research from which the underlying technologies would become an important stake for the human being.
