10.1021/acs.langmuir.5b00324.s001
Myoung Kim
Myoung
Kim
Altantuya Ochirbat
Altantuya
Ochirbat
Hyo Joong Lee
Hyo Joong
Lee
CuS/CdS Quantum Dot Composite Sensitizer and Its Applications
to Various TiO<sub>2</sub> Mesoporous Film-Based Solar Cell Devices
American Chemical Society
2015
sensitizing power
SILAR
CdS QD sensitizers
charge transfer
circuit voltage
nucleation site
sulfide anion
metal cation
light absorption
power conversion efficiency
polysulfide electrolyte
transmission electron microscopy images
CdS quantum dots
layer adsorption
MK
FF
CuS
sensitizing range
QD sensitizer
0.65 V
sensitizing system
optimized ratio
Voc decay measurements
TiO 2
CdS sensitizer
2015-07-14 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/CuS_CdS_Quantum_Dot_Composite_Sensitizer_and_Its_Applications_to_Various_TiO_sub_2_sub_Mesoporous_Film_Based_Solar_Cell_Devices/2150464
A nanoscale composite sensitizer
composed of CuS and CdS quantum
dots (QDs) was prepared by a simple but effective layer-by-layer reaction
between a metal cation (Cu<sup>2+</sup> or Cd<sup>2+</sup>) and a
sulfide anion (S<sup>2–</sup>). The as-prepared composite CuS/CdS
QD sensitizer displayed an enhanced photon-to-current conversion over
the sensitizing range of the visible spectrum compared to the counterpart
of the pure CdS sensitizer. At the optimized ratio of the deposited
amounts of CuS and CdS, the best CuS/CdS-sensitized mesoporous TiO<sub>2</sub> cell with a polysulfide electrolyte showed an overall power
conversion efficiency of 3.60% with a short circuit current (<i>J</i><sub>sc</sub>) of 11.77 mA/cm<sup>2</sup>, an open circuit
voltage (<i>V</i><sub>oc</sub>) of 0.65 V, and a fill factor
(FF) of 0.47. From the transmission electron microscopy images, the
initially deposited CuS seemed to take a nucleation site to accumulate
more CdS in the later deposition. The kinetic studies by impedance
and <i>V</i><sub>oc</sub> decay measurements also revealed
that the CuS/CdS and CdS QD sensitizers made a similar interface between
TiO<sub>2</sub> and the electrolyte, but the former had a larger resistance
of charge transfer with a longer lifetime of excitons after light
absorption than the latter. To enhance the sensitizing power further,
a multilayer QD sensitizer of CuS/CdS/CdSe was prepared by successive
ionic layer adsorption and reaction (SILAR). This led to the best
performance of 4.32% overall power conversion efficiency. Finally,
a hybrid sensitizing system of inorganic QD (CuS/CdS) and organic
dye (coded MK-2) was tested with a [Co(bpy)<sub>3</sub>]<sup>2+/3+</sup> redox mediator. The CuS/CdS/MK-2 dye-sensitized cell showed over
3.0% efficiency under the standard illumination condition (1 sun).