Memorias de investigación
Ponencias en congresos:
Two-photon photocurrent and voltage up-conversion in a quantum dot intermediate band solar cell
Año:2014
Áreas de investigación
  • Dispositivos fotónicos receptores de luz,
  • Células solares,
  • Tecnología de dispositivos para ingeniería eléctrica y electrónica
Datos
Descripción
It has been proposed that the use of self-assembled quantum dot (QD) arrays can break the Shockley-Queisser efficiency limit by extending the absorption of solar cells into the low-energy photon range while preserving their output voltage. This would be possible if the infrared photons are absorbed in the two sub-bandgap QD transitions simultaneously and the energy of two photons is added up to produce one single electron-hole pair, as described by the intermediate band model. Here, we present an InAs/Al 0.25Ga 0.75As QD solar cell that exhibits such electrical up-conversion of low-energy photons. When the device is monochromatically illuminated with 1.32 eV photons, open-circuit voltages as high as 1.58 V are measured (for a total gap of 1.8 eV). Moreover, the photocurrent produced by illumination with photons exciting the valence band to intermediate band (VB-IB) and the intermediate band to conduction band (IB-CB) transitions can be both spectrally resolved. The first corresponds to the QD inter-band transition and is observable for photons of energy > 1 eV, and the later corresponds to the QD intra-band transition and peaks around 0.5 eV. The voltage up-conversion process reported here for the first time is the key to the use of the low-energy end of the solar spectrum to increase the conversion efficiency, and not only the photocurrent, of single-junction photovoltaic devices. In spite of the low absorption threshold measured in our devices - 0.25 eV - we report open-circuit voltages at room temperature as high as 1.12 V under concentrated broadband illumination.
Internacional
Si
Nombre congreso
40th IEEE Photovoltaic Specialists Conference
Tipo de participación
960
Lugar del congreso
Denver, CO, USA
Revisores
Si
ISBN o ISSN
978-1-4799-4398-2
DOI
10.1109/pvsc.2014.6925629
Fecha inicio congreso
08/06/2014
Fecha fin congreso
13/06/2014
Desde la página
3251
Hasta la página
3253
Título de las actas
Proc. 40th IEEE PVSC
Esta actividad pertenece a memorias de investigación
Participantes
Grupos de investigación, Departamentos, Centros e Institutos de I+D+i relacionados
  • Creador: Grupo de Investigación: Silicio y Nuevos Conceptos para Células Solares
  • Departamento: Electrónica Física
  • Centro o Instituto I+D+i: Instituto de Energía Solar