TY - JOUR
T1 - Bifacial n-type silicon solar cells for upconversion applications
AU - Rüdiger, Marc
AU - Fischer, Stefan
AU - Frank, Judith
AU - Ivaturi, Aruna
AU - Richards, Bryce S.
AU - Krämer, Karl W.
AU - Hermle, Martin
AU - Goldschmidt, Jan Christoph
PY - 2014/9/30
Y1 - 2014/9/30
N2 - Upconversion of sub-band-gap photons has the potential to increase the
efficiency of solar cells significantly, but requires modification of
the solar cells. In this paper, we present a calculation framework to
assess the efficiency of a combined bifacial silicon solar cell
upconverter device, which is then used to optimize the solar cell׳s
front and rear side anti-reflection coatings. Our calculations show that
an upconverter can increase the efficiency of an optimized solar cell
by 3.0% relative. Subsequently, planar bifacial n-type silicon
solar cells were fabricated with optimized anti-reflection coatings. An
upconversion layer – containing the upconverter phosphor β-NaY0.8Er0.2F4
embedded in the polymer perfluorocyclobutyl – was attached to the rear
side of the solar cells and an external quantum efficiency arising from
the upconversion of sub-band-gap photons of 1.69% was measured under
1508 nm monochromatic excitation with an irradiance of 1091 W/m2. This corresponds to a value of 0.15 (W/cm2)−1
when normalized to the irradiance, constituting a five-fold increase
compared to the previously best published normalized values that were
achieved without optimized solar cells.
AB - Upconversion of sub-band-gap photons has the potential to increase the
efficiency of solar cells significantly, but requires modification of
the solar cells. In this paper, we present a calculation framework to
assess the efficiency of a combined bifacial silicon solar cell
upconverter device, which is then used to optimize the solar cell׳s
front and rear side anti-reflection coatings. Our calculations show that
an upconverter can increase the efficiency of an optimized solar cell
by 3.0% relative. Subsequently, planar bifacial n-type silicon
solar cells were fabricated with optimized anti-reflection coatings. An
upconversion layer – containing the upconverter phosphor β-NaY0.8Er0.2F4
embedded in the polymer perfluorocyclobutyl – was attached to the rear
side of the solar cells and an external quantum efficiency arising from
the upconversion of sub-band-gap photons of 1.69% was measured under
1508 nm monochromatic excitation with an irradiance of 1091 W/m2. This corresponds to a value of 0.15 (W/cm2)−1
when normalized to the irradiance, constituting a five-fold increase
compared to the previously best published normalized values that were
achieved without optimized solar cells.
KW - anti-reflection coatings
KW - bifacial solar cells
KW - efficiency limits
KW - n-type silicon solar cells
KW - upconversion
UR - http://www.scopus.com/inward/record.url?scp=84901929972&partnerID=8YFLogxK
U2 - 10.1016/j.solmat.2014.05.014
DO - 10.1016/j.solmat.2014.05.014
M3 - Article
AN - SCOPUS:84901929972
VL - 128
SP - 57
EP - 68
JO - Solar Energy Materials and Solar Cells
JF - Solar Energy Materials and Solar Cells
SN - 0927-0248
ER -