5 research outputs found
Efficient All-Printable Solid-State Dye-Sensitized Solar Cell Based on a Low-Resistivity Carbon Composite Counter Electrode and Highly Doped Hole Transport Material
Monolithic device architectures provide
a route to large-area mesoporous
solar cell manufacture through scalable solution-processed fabrication.
A limiting factor in device scale-up is availability of low-resistivity
printable counter electrode materials and reliable doped charge transport
materials. We report an efficient all-printable monolithic solid-state
dye-sensitized solar cell (ss-DSC) based on a high-conductivity porous
carbon counter electrode and a highly doped 2,2′,7,7′-tetrakisÂ(<i>N</i>,<i>N</i>-di-4-methoxyÂphenylÂamino)-9,9′-spiroÂbiÂfluorene
(spiro-OMeTAD) hole transport material (HTM). A review of current
state-of-the-art printable porous counter electrodes in DSC literature
was conducted and identified blends of graphite/carbon black as promising
composites for high-conductivity electrodes. Direct ex situ oxidation
of spiro-OMeTAD produced a stable HTM dopant, and its incorporation
with one of the lowest-resistivity graphite/carbon black composite
materials reported to date drastically decreases device series resistance,
particularly that of the porous insulating spacer. Doping improved
all performance parameters, and following optimization we demonstrate
scaled-up 1.21 cm<sup>2</sup> (1.01 cm<sup>2</sup> masked) devices
achieving a maximum efficiency of 3.34% (average, 3.05 ± 0.23%)
Additional file 1 of Transition models of care for type 1 diabetes: a systematic review
Supplementary Material
Additional file 2 of Transition models of care for type 1 diabetes: a systematic review
Supplementary Material
Tunable Crystallization and Nucleation of Planar CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> through Solvent-Modified Interdiffusion
A smooth
and compact light absorption perovskite layer is a highly desirable
prerequisite for efficient planar perovskite solar cells. However,
the rapid reaction between CH<sub>3</sub>NH<sub>3</sub>I methylammonium
iodide (MAI) and PbI<sub>2</sub> often leads to an inconsistent CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> crystal nucleation and growth
rate along the film depth during the two-step sequential deposition
process. Herein, a facile solvent additive strategy is reported to
retard the crystallization kinetics of perovskite formation and accelerate
the MAI diffusion across the PbI<sub>2</sub> layer. It was found that
the ultrasmooth perovskite thin film with narrow crystallite size
variation can be achieved by introducing favorable solvent additives
into the MAI solution. The effects of dimethylformamide, dimethyl
sulfoxide, γ-butyrolactone, chlorobenzene, and diethyl ether
additives on the morphological properties and cross-sectional crystallite
size distribution were investigated using atomic force microscopy,
X-ray diffraction, and scanning electron microscopy. Furthermore,
the light absorption and band structure of the as-prepared CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> films were investigated and
correlated with the photovoltaic performance of the equivalent solar
cell devices. Details of perovskite nucleation and crystal growth
processes are presented, which opens new avenues for the fabrication
of more efficient planar solar cell devices with these ultrasmooth
perovskite layers
The Influence of the Work Function of Hybrid Carbon Electrodes on Printable Mesoscopic Perovskite Solar Cells
In
printable mesoscopic perovskite solar cells (PSCs), carbon electrodes
play a significant role in charge extraction and transport, influencing
the overall device performance. The work function and electrical conductivity
of the carbon electrodes mainly affect the open-circuit voltage (<i>V</i><sub>OC</sub>) and series resistance (<i>R</i><sub>s</sub>) of the device. In this paper, we propose a hybrid carbon
electrode based on a high-temperature mesoporous carbon (m-C) layer
and a low-temperature highly conductive carbon (c-C) layer. The m-C
layer has a high work function and large surface area and is mainly
responsible for charge extraction. The c-C layer has a high conductivity
and is responsible for charge transport. The work function of the
m-C layer was tuned by adding different amounts of NiO, and at the
same time, the conductivities of the hybrid carbon electrodes were
maintained by the c-C layer. It was supposed that the increase of
the work function of the carbon electrode can enhance the <i>V</i><sub>OC</sub> of printable mesoscopic PSCs. Here, we found
the <i>V</i><sub>OC</sub> of the device based on hybrid
carbon electrodes can be enhanced remarkably when the insulating layer
has a relatively small thickness (500–1000 nm). An optimal
improvement in <i>V</i><sub>OC</sub> of up to 90 mV could
be achieved when the work function of the m-C was increased from 4.94
to 5.04 eV. When the thickness of the insulating layer was increased
to ∼3000 nm, the variation of <i>V</i><sub>OC</sub> as the work function of m-C increased became less distinct