Conventional solar cells based on silicon semiconductors, can only absorb visible photons with a particular amount of energy, which is then transfered to the trapped electrons. Unfortunately, these conventional systems cannot use visible photons that contain more or less than a certain amount of energy, making then quite inefficient.
However some advances were made in 1997 by another Spanish scientist, who found a way to increase that usable spectrum of visible photons. He found a way to collect the lower energy photons and store them until another lower energy photon was absorbed and then combine them to make the electron jump. Even though these advances were quite significant, the theoretical efficiency of silicon based solar cell have still remained under 40%.
That is, until now…
A couple of scientist in Madrid, Spain have invented a new type of solar cell which not only collects visible light, but captures the energy of non-visible infrared light. These scientist have devised a way to create an intermediate energy level for collecting visible and non-visible low level energy photons, by adding vanadium and titanium to the semi-conductors. Instead of collecting two low level photons and combining them to make them jump to the full energy level, the titanium and vanadium actually alters the electronics of the semi-conductors allowing them to absorb and jump on intermediate energy levels. This new advancement according to the team will give these new solar cells a theoretical efficiency of 63%.
via NewSientist