Feedback-driven optimization of hot-carrier solar cell
Publicerad
Författare
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Solar cells convert energy absorbed from the sun into electrical power and they are
therefore of high interest for green energy solutions. Ongoing research to improve
solar cells deals with a broad range of aspects from improved light absorption to
pushing the limits of efficiency searching for keys in materials research and device
design.
Hot-carrier solar cells, which are at the focus of this thesis aim at improving the
output power of a solar cell by exploiting the excess energy of the light-generated
charge carriers, which is lost in fast relaxation processes in standard solar cells. The
drawback of these hot-carrier solar cells is however that low-energy charge carriers
are not exploited for power generation.
In this thesis, we propose and theoretically analyse a feedback mechanism to adapt
the energy-filtering scheme for the extraction of hot carriers to the nonequilibrium
conditions under which the solar cell is operated. This is done by coupling a quantum
dot to the electron collector, which thereby measures the collector’s potential. This
quantum dot is furthermore capacitively coupled to the energy filter, so that it
modifies its properties depending on the collector potential. We demonstrate that
this feedback can improve the charging time, when the solar cell is used to charge
a battery, and it can improve the power generated, when the solar cell is connected
to a circuit with a load.
In this thesis we use a scattering matrix approach to model the solar cell operation.
The load resistance or battery capacitance, as well as the filter properties enter the
model through general variables, which could in the future be adapted to experimentally
relevant conditions, in order to test the opportunities of this proposal for
realistic devices.
Beskrivning
Ämne/nyckelord
solar cells, hot carrier solar cell, quantum dot, quantum point contact, feedback optimization