TiO 2 nanorods were synthesized by the hydrothermal methods with ethanol-HCl and water-HCl solutions, respectively, and CH 3 NH 3 PbI 3-x Cl x perovskite solar cells based on them were fabricated. The power conversion efficiency (PCE) of the best solar cells based on TiO 2 nanorods with water-HCl solution is higher than that with ethanol-HCl solution. The dimension, morphology, optical property, and photogenerated charge behavior of the two kinds of samples were investigated. The results indicate that the better performance of solar cells based TiO 2 nanorods with water-HCl solution than that with ethanol-HCl solution could be attributed to its special orientation, high conductivity, improved morphology, good optical property, fast charge transfer and reduced charge recombination. The PCE of 11.8% was achieved using the TiO 2 nanorods with water-HCl solution, which is the highest in the reported TiO 2 nanorods based cells.
Extending photoelectric response
to the near-infrared (NIR) region
using upconversion luminescent (UCL) materials is one promising approach
to obtain high-efficiency perovskite solar cells (PSCs). However,
challenges remain due to the shortage of highly efficient UCL materials
and device structure. NaCsWO3 nanocrystals exhibit near-infrared
absorption arising from the local surface plasmon resonance (LSPR)
effect, which can be used to boost the UCL of rare-earth-doped upconversion
nanoparticles (UCNPs). In this study, using NaCsWO3 as
the LSPR center, NaCsWO3@NaYF4@NaYF4:Yb,Er nanoparticles were synthesized and the UCL intensity could
be enhanced by more than 124 times when the amount of NaCsWO3 was 2.8 mmol %. Then, such efficient UCNPs were not only doped into
the hole transport layer but also used to modify the perovskite film
in PSCs, resulting in the highest power conversion efficiency (PCE)
reaching 18.89% (that of the control device was 16.01% and the PCE
improvement was 17.99%). Possible factors for the improvement of PSCs
were studied and analyzed. It is found that UCNPs can broaden the
response range of PSCs to the NIR region due to the LSPR-enhanced
UCL and increase the visible light reabsorption of PSCs due to the
scattering and reflection effect, which generate more photocurrent
in PSCs. In addition, UCNPs modify the perovskite film by effectively
filling the holes and gaps at the grain boundary and eliminating the
perovskite surface defects, which lead to less carrier recombination
and then effectively improve the performance of PSC devices.
The aggregation and fibril formation of amyloid β(Aβ) peptides onto a ganglioside-GM1-containing lipid membrane is a cause of neurodegenerative diseases. The mechanism of the initial binding and the conformational changes of Aβ on the membrane should be clarified. Fluorescence microscopy and Raman spectroscopy have been performed to investigate the supporting planar lipid bilayers (SPBs) composed of ganglioside-GM1, sphingomyelin and cholesterol. It is demonstrated that the SPBs are in a liquid-crystalline state when placed on mica, and increasing the amount of ganglioside-GM1 can decrease the lateral interaction between the acyl chains of the SPBs. It has been found that Aβ(1-40) initially interacts with the galactose ring of the ganglioside-GM1 head group, leading to its binding and gradual aggregation on the membrane surface. The obvious change observed in Raman spectroscopy in the ν(C-H) region confirms that the hydrophobic C-terminal of Aβ(1-40) inserts itself into the hydrophobic part of the SPBs. The Raman data indicate that α-helix and β-sheet structures of Aβ(1-40) increase and coexist over longer time frames. Based on these results, a model was proposed to describe the mechanism of the conformational changes and the aggregation of Aβ(1-40) that are mediated by ganglioside-GM1-containing SPBs.
Perovskite solar cells (PSCs) have attracted tremendous attentions due to its high performance and rapid efficiency promotion. Compact layer plays a crucial role in transferring electrons and blocking charge recombination between the perovskite layer and fluorine-doped tin oxide (FTO) in PSCs. In this study, compact TiO2 layers were synthesized by spin-coating method with three different titanium precursors, titanium diisopropoxide bis (acetylacetonate) (c-TTDB), titanium isopropoxide (c-TTIP), and tetrabutyl titanate (c-TBOT), respectively. Compared with the PSCs based on the widely used c-TTDB and c-TTIP, the device based on c-TBOT has significantly enhanced performance, including open-circuit voltage, short-circuit current density, fill factor, and hysteresis. The significant enhancement is ascribed to its excellent morphology, high conductivity and optical properties, fast charge transfer, and large recombination resistance. Thus, a power conversion efficiency (PCE) of 17.03% has been achieved for the solar cells based on c-TBOT.Electronic supplementary materialThe online version of this article (10.1186/s11671-017-2418-9) contains supplementary material, which is available to authorized users.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.