4 research outputs found
Iodine and Chlorine Element Evolution in CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<sub><i>x</i></sub> Thin Films for Highly Efficient Planar Heterojunction Perovskite Solar Cells
Highly efficient planar heterojunction
perovskite solar cells (PHJ–PSCs)
with a structure of ITO/PEDOT:PSS/CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<sub><i>x</i></sub>/PCBM/C<sub>60</sub>/Ag was fabricated, in which the compact and pinhole-free
CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<sub><i>x</i></sub> perovskite thin film was obtained
using a mixture of precursors containing lead iodide (PbI<sub>2</sub>), lead chloride (PbCl<sub>2</sub>), and methylammonium iodide (CH<sub>3</sub>NH<sub>3</sub>I) at an optimized ratio of 1:1:4. The morphology
and formation process of CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<sub><i>x</i></sub> thin film was closely
related to the annealing temperature and time, which would result
in the controllable performance for the PHJ–PSC devices. The
morphology, crystallization process, and element analysis suggested
that the chlorine gradually diffused and sublimated from the film
surface while the iodine moved to the surface, together with the removal
of the pinholes in the film. The PHJ–PSCs with the as-prepared
CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<sub><i>x</i></sub> thin film showed good performance
and excellent repeatability. The power conversion efficiency (PCE)
up to 14.03% was achieved without obvious hysteresis under different
scanning conditions. The understanding of the iodine and chlorine
element evolving process during the thermal treatment is beneficial
to develop a more efficient scalable one-step solution processing
method for fabricating large-area, highly efficient CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3–<i>x</i></sub>Cl<sub><i>x</i></sub>-based PSCs
Prominent Efficiency Enhancement in Perovskite Solar Cells Employing Silica-Coated Gold Nanorods
Highly efficient planar heterojunction
(PHJ) perovskite solar cells
(PSCs) with a structure of ITO/PEDOT:PSS/CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>/PCBM/Al were fabricated by a low-temperature solution
process. As employed silica-coated gold (Au@SiO<sub>2</sub>) nanorods
at the interface between the hole transport layer PEDOT:PSS and the
active layer CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>, the average
power conversion efficiency (PCE) showed over 40% enhancement, of
which the average PCE was improved from 10.9% for PHJ-PSCs without
Au@SiO<sub>2</sub> to 15.6% for PHJ-PSCs with Au@SiO<sub>2</sub>,
and the champion one up to 17.6% was achieved. Both experiment and
simulation results proved that prominent efficiency enhancement comes
from the localized surface plasmon resonance of Au@SiO<sub>2</sub> nanorods which could improve the incident light trapping as well
as improve the transport and collection of charge carrier, resulting
in the enhancement in device parameters. The results suggest that
metal nanorods, e.g., Au@SiO<sub>2</sub>, could be employed to fabricate
high-efficiency and low-cost PHJ-PSCs
Air-Induced High-Quality CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> Thin Film for Efficient Planar Heterojunction Perovskite Solar Cells
Efficient
planar heterojunction perovskite solar cells (PHJ–PSCs)
with a structure of ITO/PEDOT:PSS/CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub>/PCBM/Al were fabricated using air-induced high-quality CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> perovskite thin films, in which
the air-inducing process was controlled with a humidity of ∼40%.
The air exposure of CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> thin
films could dramatically improve their properties with large grains
and smooth surface, as well as uniform morphology, resulting in an
impressive enhancement in carrier lifetime. The ultraviolet photoelectron
spectroscopy and X-ray photoelectron spectroscopy results proved that
the CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> film was <i>n</i>-doped by the absorption of H<sub>2</sub>O on the surface but was
very stable without obvious degradation for 10 days’ exposure
in air. The power conversion efficiency (PCE) of PHJ–PSCs with
an air exposure process showed a significant increase up to 16.21%
as compared to reference PHJ–PSCs with a PCE of 12.02%. The
research work demonstrated that an air-exposure process with a suitable
humidity could produce high-quality perovskite thin film for efficient
PHJ–PSCs, which may pave a boulevard for fabricating high-efficiency
PHJ–PSCs in atmospheric environment
Silane-Capped ZnO Nanoparticles for Use as the Electron Transport Layer in Inverted Organic Solar Cells
Zinc
oxide (ZnO) nanoparticles are widely used as electron- transport
layer (ETL) materials in organic solar cells and are considered to
be the candidate with the most potential for ETLs in roll-to-roll
(R2R)-printed photovoltaics. However, the tendency of the nanoparticles
to aggregate reduces the stability of the metal oxide inks and creates
many surface defects, which is a major barrier to its printing application.
With the aim of improving the stability of metal oxide nanoparticle
dispersions and suppressing the formation of surface defects, we prepared
3-aminopropyltrimethoxysilane (APTMS)-capped ZnO (ZnO@APTMS) nanoparticles
through surface ligand exchange. The ZnO@APTMS nanoparticles exhibited
excellent dispersibility in ethanol, an environmentally friendly solvent,
and remained stable in air for at least one year without any aggregation.
The capping of the ZnO nanoparticles with APTMS also reduced the number
of surface-adsorbed oxygen defects, improved the charge transfer efficiency,
and suppressed the light-soaking effect. The thickness of the ZnO@APTMS
ETL could reach 100 nm without an obvious decrease in the performance.
Large-area APTMS-modified ZnO films were successfully fabricated through
roll-to-roll microgravure printing and exhibited good performance
in flexible organic solar cells. This work demonstrated the distinct
advantages of this ZnO@APTMS ETL as a potential buffer layer for printed
organic electronics