TY  - CONF
T2  - 23rd European Photovoltaic Solar Energy Conference
CY  - Munich, Alemania
KW  - High Efficiency; Intermediate Band; Quantum Dots
UR  - https://oa.upm.es/3578/
SN  - 3-936338-24-8
Y1  - 2008///
AV  - public
A1  - Antolín Fernández, Elisa
A1  - Martí Vega, Antonio
A1  - García-Linares Fontes, Pablo
A1  - Cánovas Díaz, Enrique
A1  - Fuertes Marrón, David
A1  - Luque López, Antonio
A1  - Farmer, C.D.
A1  - Stanley, Colin
TI  - Demonstration and Analysis of the Photocurrent by absorption of two sub-bandgap photons in a quantum dot intermediate band solar cell
N2  - In order to surpass the efficiency limit of single gap solar cells, intermediate band solar cells (IBSC)  have to fulfill two requirements: the production of extra photocurrent by absorption of sub-bandgap photons in  electronic transitions involving the intermediate band (IB) and the preservation of a high output voltage, not limited  by the existence of this band. This work presents experimental evidence of the production of electron-hole pairs by  absorption of two sub-bandgap photons in IBSC prototypes fabricated with InAs/GaAs QD material. The  experiments were carried out at low temperatures using a specifically designed modulated photocurrent measurement  set-up with two light beams. The results are analysed with the help of a simple equivalent circuit model. This  analysis is also used to highlight the relevance of the two-photon mechanism demonstrated in the experiment. It is  discussed that, although the absorption of sub-bandgap photons in one of the IB transitions and subsequent thermal  escape of carriers is a sufficient mechanism to obtain a photocurrent enhancement, the absorption of sub-bandgap  photons in both transitions involving the IB is a requisite for the voltage preservation in IBSCs.
M2  - Valencia, España
ID  - upm3578
PB  - WIP-Renewable Energie
ER  -