10 research outputs found
Benzimidazole-Branched Isomeric Dyes: Effect of Molecular Constitution on Photophysical, Electrochemical, and Photovoltaic Properties
Three
benzimidazole-based isomeric organic dyes possessing two triphenylamine
donors and a cyanoacrylic acid acceptor are prepared by stoichiometrically
controlled Stille or Suzuki–Miyaura coupling reaction which
predominantly occurs on the <i>N</i>-butyl side of benzimidazole
due to electronic preferences. Combined with the steric effect of
the <i>N</i>-butyl substituent, placement of the acceptor
segment at various nuclear positions of benzimidazole such as C2,
C4, and C7 led to remarkable variations in intramolecular charge transfer
absorption, electron injection efficiency, and charge recombination
kinetics. The substitution of acceptor on the C4 led to red-shifted
absorption, while that on C7 retarded the charge transfer due to twisting
in the structure caused by the butyl group. Because of the cross-conjugation
nature and poor electronic interaction between the donor and acceptor,
the dye containing triphenylamine units on C4 and C7 and the acceptor
unit on C2 showed the low oxidation potential. Thus, this dye possesses
favorable HOMO and LUMO energy levels to render efficient sensitizing
action in solar cells. Consequently, it results in high power conversion
efficiency (5.01%) in the series with high photocurrent density and
open circuit voltage. The high photocurrent generation by this dye
is reasoned to it exceptional charge collection efficiency as determined
from the electron impedance spectroscopy
Nanoflower-like P-doped Nickel Oxide as a Catalytic Counter Electrode for Dye-Sensitized Solar Cells
Flower-like phosphorus-doped nickel oxide (P-NiO) is proposed as a counter electrode (CE) for dye-sensitized solar cells (DSSCs). The flower-like nickel oxide essentially serves as the matrix for the CE, which is expected to promote a two-dimensional electron transport pathway. The phosphorus is intended to improve the catalytic ability by creating more active sites in the NiO for the catalysis of triiodide ions (I3−) to iodide ions (I−) on the surface of the CE. The P-NiO is controlled by a sequencing of precursor concentration, which allows the P-NiO to possess different features. The debris aggregation occurs in the P-NiO-1, while the P-NiO-0.75 leads to the incomplete flower-like nanosheets. The complete flower-like morphology can be observed in the P-NiO-0.5, P-NiO-0.25 and P-NiO-0.1 catalytic electrodes. The DSSC with the P-NiO-0.5 CE achieves a power conversion efficiency (η) of 9.05%, which is better than that of the DSSC using a Pt CE (η = 8.51%); it also performs better than that with the Pt CE, even under rear illumination and dim light conditions. The results indicate the promising potential of the P-NiO CE to replace the expensive Pt CE
Prussian blue-derived synthesis of hollow porous iron pyrite nanoparticles as platinum-free counter electrodes for highly efficient dye-sensitized solar cells
Iron pyrite has long been an attractive material for environmental and energy applications, but is hampered by a lack of control over morphology and purity. Hollow porous iron pyrite nanoparticles were synthesized by a direct sulfurization of iron oxide derived from Prussian blue. The high efficiencies of these hollow porous iron pyrite nanoparticles as effective dye-sensitized solar cell counter electrodes were demonstrated, with an efficiency of 7.31%
A high contrast solid-state electrochromic device based on nano-structural Prussian blue and poly(butyl viologen) thin films
Microemulsion-assisted Zinc Oxide Synthesis: Morphology Control and Its Applications in Photoanodes of Dye-Sensitized Solar Cells
Nitrogen-doped graphene/molybdenum disulfide composite as the electrocatalytic film for dye-sensitized solar cells
Effect of auxiliary donors and position of benzothiadiazole on the optical and photovoltaic properties of dithieno[3,2-b:2′,3′-d]pyrrole-based sensitizers
MoSe2 nanosheet/poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) composite film as a Pt-free counter electrode for dye-sensitized solar cells
Performance Characterization of Dye-Sensitized Photovoltaics under Indoor Lighting
Indoor
utilization of emerging photovoltaics is promising; however,
efficiency characterization under room lighting is challenging. We
report the first round-robin interlaboratory study of performance
measurement for dye-sensitized photovoltaics (cells and mini-modules)
and one silicon solar cell under a fluorescent dim light. Among 15
research groups, the relative deviation in power conversion efficiency
(PCE) of the samples reaches an unprecedented 152%. On the basis of
the comprehensive results, the gap between photometry and radiometry
measurements and the response of devices to the dim illumination are
identified as critical obstacles to the correct PCE. Therefore, we
use an illuminometer as a prime standard with a spectroradiometer
to quantify the intensity of indoor lighting and adopt the reverse-biased
current–voltage (<i>I</i>–<i>V</i>) characteristics as an indicator to qualify the <i>I</i>–<i>V</i> sampling time for dye-sensitized photovoltaics.
The recommendations can brighten the prospects of emerging photovoltaics
for indoor applications