3 research outputs found
Quantum Dot Solar Cell Fabrication Protocols
Colloidally
synthesized quantum-confined semiconducting spherical
nanocrystals, often referred to as quantum dots (QDs), offer a high
degree of chemical, optical, and electronic tunability. As a result,
there is an increasing interest in employing colloidal QDs for electronic
and optical applications that is reflected in a growing number of
publications. In this protocol we provide detailed procedures for
the fabrication of QD solar cells specifically employing PbSe and
PbS QDs. We include details that are learned through experience, beyond
those in typical methodology sections, and include example pictures
and videos to aid in fabricating QD solar cells. Although
successful solar cell fabrication is ultimately learned through experience,
this protocol is intended to accelerate that process. The protocol
developed here is intended to be a general starting point for developing
PbS and PbSe QD test bed solar cells. We include steps for forming
conductive QD films via dip coating as well as spin coating. Finally,
we provide protocols that detail the synthesis of PbS and PbSe QDs
through a unique cation exchange reaction and discuss how different
QD synthetic routes could impact the resulting solar cell performance
Quantum Dot Solar Cell Fabrication Protocols
Colloidally
synthesized quantum-confined semiconducting spherical
nanocrystals, often referred to as quantum dots (QDs), offer a high
degree of chemical, optical, and electronic tunability. As a result,
there is an increasing interest in employing colloidal QDs for electronic
and optical applications that is reflected in a growing number of
publications. In this protocol we provide detailed procedures for
the fabrication of QD solar cells specifically employing PbSe and
PbS QDs. We include details that are learned through experience, beyond
those in typical methodology sections, and include example pictures
and videos to aid in fabricating QD solar cells. Although
successful solar cell fabrication is ultimately learned through experience,
this protocol is intended to accelerate that process. The protocol
developed here is intended to be a general starting point for developing
PbS and PbSe QD test bed solar cells. We include steps for forming
conductive QD films via dip coating as well as spin coating. Finally,
we provide protocols that detail the synthesis of PbS and PbSe QDs
through a unique cation exchange reaction and discuss how different
QD synthetic routes could impact the resulting solar cell performance
Tandem Solar Cells from Solution-Processed CdTe and PbS Quantum Dots Using a ZnTe–ZnO Tunnel Junction
We developed a monolithic
CdTe–PbS tandem solar cell architecture in which both the CdTe
and PbS absorber layers are solution-processed from nanocrystal inks.
Due to their tunable nature, PbS quantum dots (QDs), with a controllable
band gap between 0.4 and ∼1.6 eV, are a promising candidate
for a bottom absorber layer in tandem photovoltaics. In the detailed
balance limit, the ideal configuration of a CdTe (<i>E</i><sub>g</sub> = 1.5 eV)–PbS tandem structure assumes infinite
thickness of the absorber layers and requires the PbS band gap to
be 0.75 eV to theoretically achieve a power conversion efficiency
(PCE) of 45%. However, modeling shows that by allowing the thickness
of the CdTe layer to vary, a tandem with efficiency over 40% is achievable
using bottom cell band gaps ranging from 0.68 and 1.16 eV. In a first
step toward developing this technology, we explore CdTe–PbS
tandem devices by developing a ZnTe–ZnO tunnel junction, which
appropriately combines the two subcells in series. We examine the
basic characteristics of the solar cells as a function of layer thickness
and bottom-cell band gap and demonstrate open-circuit voltages in
excess of 1.1 V with matched short circuit current density of 10 mA/cm<sup>2</sup> in prototype devices