Memorias de investigación
Research Project:
IBPOWER: Intermediate Band Materials and Solar Cells for Photovoltaics with High Efficiency and Reduced Cost

Research Areas


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 characterised 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 (photons "1" and "2") creates one electron-hole pair that adds to the ones conventionally generated by the absorption of photons with energy higher than the bandgap EG (photon "3"). 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 accomodate 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 sandwitched between two conventional semiconductors2 (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.

Project type
Proyectos y convenios en convocatorias públicas competitivas
Comisión Europea
Entity Nationality
Entity size
Granting date

Research Group, Departaments and Institutes related
  • Grupo de Investigación: Silicio y Nuevos Conceptos para Células Solares
  • Centro o Instituto I+D+i: Instituto de Energía Solar
  • Departamento: Electrónica Física