|IBPOWER is devoted to the development of the intermediate band solar cell (IBSC) concept1. The IBSC is implemented on the basis of intermediate band materials. Typically these materials are characterized by the existence of the so-called "intermediate band" (IB) within a semiconductor bandgap. This IB splits the bandgap into two two-subbandgpas, EL and EH and allows the absorption of below-bandgap energy photons. Thanks to the IB, the absorption of two below bandgap energy photons creates one electron-hole pair that adds to the ones conventionally generated by the absorption of photons with energy higher than the bandgap EG. This increases the solar cell photocurrent. In order to be able to absorb the two below bandgap energy photons, the IB must be partially filled with electrons so it can provide both empty states to accommodate electrons from the valence band (VB) as to provide electrons to be pumped to the conduction band (CB) However, increasing the cell photocurrent is not enough (it could be easily done by choosing a low bandgp semiconductor for manufacturing the cell) if the potential for achieving a high output voltage is not preserved. To this end, according to the fundamental IBSC theory, the IB material must be sandwiched between two conventional semiconductors (emitters) to isolate the IB from the electrical contacts. The output voltage is determined then by the electron and hole quasi-Fermi level split (eV=EFE-EFH) and is still limited by the total bandgap EG. The project pursues the implementation of the IBSC through different research lines, as for example: The use of quantum dots, the creation of low cost thin-film intermediate band materials, etc.
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