3 research outputs found
Solubility of Dilute SO<sub>2</sub> in Mixtures of <i>N</i>,<i>N</i>‑Dimethylformamide + Polyethylene Glycol 400 and the Density and Viscosity of the Mixtures
In this work, the isothermal gas–liquid equilibrium
(GLE)
data were measured for the system of polyethylene glycol 400 (PEG
400) + <i>N</i>,<i>N</i>-dimethylformamide (DMF)
+ SO<sub>2</sub> + N<sub>2</sub> at 308.15 K and 123 kPa with SO<sub>2</sub> partial pressures in the range of (16.8 to 115) Pa. The Henry’s
law constant (<i>H</i>′) and standard Gibbs free
energy change (Δ<i>G</i>) were calculated from these
GLE data. Furthermore, the densities and viscosities of binary mixtures
of DMF + PEG 400 were also measured over the whole concentration range
at <i>T</i> = (298.15 to 313.15) K. From the experimental
data, including density and viscosity values, the excess molar volumes
(<i>V</i><sub>m</sub><sup>E</sup>), and viscosity deviations
(Δη), the calculated results are fitted to a Redlich–Kister
equation to obtain the coefficients and estimate the standard deviations
between the experimental and the calculated quantities
Surface Decorating of CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> Nanoparticles with the Chemically Adsorbed Perylenetetracarboxylic Diimide
An organic dye-modified organolead
halide CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> nanoparticle (cubic)
is prepared successfully
by using a perylenetetracarboxylic diimide (PDI) bearing an -NH<sub>3</sub><sup>+</sup> headgroup as the capping ligand. The nanopartilces
are homogeneous with high crystallinity. The photoluminescence of
perovskite is quenched completely by the chemically adsorbed PDI molecules.
This efficient fluorescence quenching has confirmed that the PDI molecules
are anchored on the surface of CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> nanoparticle. The resulting nanoparticles can be dispersed
in organic solvents, and the resulting dispersion remains stable for
days. This result provides a general guideline for surface engineering
of organolead halide CH<sub>3</sub>NH<sub>3</sub>PbBr<sub>3</sub> nanoparticles
Surface Modification of Methylamine Lead Halide Perovskite with Aliphatic Amine Hydroiodide
By spin-coating method,
a thin layer of dodecylamine hydroiodide
(DAHI) is introduced to the surface of perovskite CH<sub>3</sub>NH<sub>3</sub>PbI<i><sub>x</sub></i>Cl<sub>3–<i>x</i></sub>. This layer of DAHI successfully changes the surface of perovskite
from hydrophilic to hydrophobic as revealed by the water contact angle
measurement. Significantly enhanced fluorescence intensity and prolonged
fluorescence lifetime are found for these modified films in comparison
to those of unmodified perovskite films, suggesting that the number
of structure defects is reduced dramatically. The compatibility between
the perovskite and hole transfer layer (HTL) is also improved, which
leads to more efficient hole collection from the perovskite layer
by HTL as revealed by the fluorescence spectra, fluorescence decay
dynamics, as well as the transient photocurrent measurements. Moreover,
the perovskite solar cells (PSCs) fabricated from these modified perovskite
films exhibit significantly improved humidity stability as well as
promoted photoelectron conversion efficiency (PCE). The result of
this research reveals for the first time that the layer of aliphatic
amino hydroiodide is a multiple functions layer, which can not only
improve the humidity stability but also promote the performance of
PSCs by reducing the defect number and improve the compatibility between
perovskite and HTL. Because the structure of aliphatic amines can
be functionalized with myriad of other groups, this perovskite modification
method should be very promising in promoting the performance of PSCs