Role of the spacer cation in the growth and crystal orientation of two-dimensional perovskites

2021 ◽  
Author(s):  
Nishi Parikh ◽  
Mohammad Mahdi Tavakoli ◽  
Manoj Pandey ◽  
Abul Kalam ◽  
Daniel Prochowicz ◽  
...  
Keyword(s):  
Thin Films ◽  
Crystal Orientation ◽  
Two Dimensional ◽  
Vertical Orientation ◽  
Halide Perovskite ◽  
The Impact

The impact of organic spacer cations on controlling the growth and crystal orientation of two dimensional halide perovskite thin films is discussed along with the mechanism for obtaining vertical orientation.

Understanding the Formation of Vertical Orientation in Two-dimensional Metal Halide Perovskite Thin Films

2019 ◽  
Vol 31 (4) ◽  
pp. 1336-1343 ◽  
Author(s):  
Alexander Z. Chen ◽  
Michelle Shiu ◽  
Xiaoyu Deng ◽  
Mustafa Mahmoud ◽  
Depei Zhang ◽  
...  
Keyword(s):  
Thin Films ◽  
Metal Halide ◽  
Two Dimensional ◽  
Vertical Orientation ◽  
Metal Halide Perovskite ◽  
Halide Perovskite

scholarly journals Nanometer-Thick [(FPEA)2PbX4; X=I, Br] 2D Halide Perovskite Based Thin Films for Pollutant Detection and Nonconventional Photocatalytic Degradation

2021 ◽  
Author(s):  
Arindam Mondal ◽  
Akash Lata ◽  
Aarya Prabhakaran ◽  
Satyajit Gupta
Keyword(s):  
Thin Films ◽  
Photocatalytic Degradation ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Reduced Dimensionality ◽  
P Application ◽  
Halide Perovskites ◽  
Halide Perovskite ◽  
Pollutant Detection

Application of three-dimensional (3D)-halide perovskites (HaP) in photocatalysis encourages the new exercise with two-dimensional (2D) HaP based thin-films for photocatalytic degradation of dye. The reduced dimensionality to 2D-HaPs, with a...

Phonon Coupling and Dielectric Response in 2D Semiconductor

NANO ◽  
2021 ◽  
Author(s):  
Arslan Usman ◽  
Abdul Sattar ◽  
Hamid Latif ◽  
Muhammad Imran
Keyword(s):  
Transition Metal Dichalcogenides ◽  
Coupling Mechanism ◽  
Two Dimensional ◽  
Electron Hole ◽  
Exciton Coupling ◽  
Gain Energy ◽  
Metal Dichalcogenides ◽  
Layered Transition Metal ◽  
The Impact

The impact of phonon and their surrounding environment on exciton and its complexes were investigated in monolayer WSe2 semiconductor. Phonon up-conversion has been studied in past for conventional III–V semiconductors, but its role in two-dimensional layered transition metal dichalcogenides has rarely been explored. We investigated the photoluminescence up-conversion mechanism in WSe2 monolayer and found that a lower energy photon gain energy upto 64[Formula: see text]meV to be up-converted to emission photon at room temperature. Moreover, the phonon-exciton coupling mechanism has also been investigated and the role of dielectric screening has been explored to get complete insight of coulomb’s interaction in these electron-hole pairs. Investigations of charge carrier’s lifetime reveal that boron nitride encapsulated monolayer has shorter recombination time as low as 41 ps as compared to a bare monolayer on SiO2 substrate. These results are very promising for realizing spintronics-based application from two-dimensional layered semiconductors.

scholarly journals The EU Falsified Medicines Directive: Key Implications for Dispensers

2017 ◽  
Vol 1 ◽  
pp. maapoc.0000024 ◽  
Author(s):  
Bernard D. Naughton
Keyword(s):  
Pharmaceutical Companies ◽  
Two Dimensional ◽  
European Directive ◽  
2D Barcode ◽  
Market Authorization ◽  
Falsified Medicines ◽  
The Impact ◽  
The Eu

The EU Falsified Medicines Directive (FMD) mandates the serialisation of prescription-only medicines using a two-dimensional (2D) barcode by pharmaceutical companies and the systematic verification of this 2D barcode in pharmacies. This European directive has ramifications for many stakeholders, including market authorization holders, wholesalers, parallel importers, and dispensers. Focusing primarily on the impact on UK dispensers, the following questions are addressed in this article: Where should the affected medicines be scanned? and who will pay for the incoming changes to practice? The role of the EU FMD in terms of drug recalls, the preparation required for EU FMD compliance, and the potential for added healthcare value are also discussed. Dispensers must prepare for the February 2019 EU FMD deadline date by choosing a point within their dispensing processes to scan medicines. Dispensers must also budget appropriately for the incoming costs associated with new hardware and processes.

INSTANTANEOUS INFORMATION ALWAYS STABILIZES?

2011 ◽  
Vol 56 (02) ◽  
pp. 239-253
Author(s):  
YANG ZHANG ◽  
WEIHONG HUANG
Keyword(s):  
Local Stability ◽  
Continuous Model ◽  
Stability Loss ◽  
Cost Structure ◽  
Bertrand Competition ◽  
Two Dimensional ◽  
Additional Stability ◽  
The Impact ◽  
Cournot And Bertrand Competition

The impact of information improvement on local stability is examined for continuous dynamics. It is conventionally believed that removal of uncertainty always brings additional stability to an existing equilibrium. This paper shows that the relation between information and equilibrium stability may not be monotonic. Removal of information lag may sometimes destabilize the otherwise stable continuous model. Economic applications to Cournot and Bertrand competition are examined where the role of improved information on stability is shown to be cost-structure specific. Elimination of lags may cause stability loss. The conclusion drawn on two-dimensional continuous dynamics is briefly generalized to multidimensional system.

The Role of Excitation Energy in Photobrightening and Photodegradation of Halide Perovskite Thin Films

2018 ◽  
Vol 9 (8) ◽  
pp. 2062-2069 ◽  
Author(s):  
Wolf-Alexander Quitsch ◽  
Dane W. deQuilettes ◽  
Oliver Pfingsten ◽  
Alexander Schmitz ◽  
Stevan Ognjanovic ◽  
...  
Keyword(s):  
Thin Films ◽  
Excitation Energy ◽  
Halide Perovskite

scholarly journals A deep insight into the ion foreshock with the help of test particle two-dimensional simulations

2020 ◽  
Vol 38 (6) ◽  
pp. 1217-1235
Author(s):  
Philippe Savoini ◽  
Bertrand Lembège
Keyword(s):  
Electric Field ◽  
Shock Front ◽  
Test Particle ◽  
Field Component ◽  
Upstream Region ◽  
Mirror Reflection ◽  
Two Dimensional ◽  
Shock Profiles ◽  
The Impact

Abstract. Two-dimensional (2D) test particle simulations based on shock profiles issued from 2D full particle-in-cell (PIC) simulations are used in order to analyze the formation processes of ions back streaming within the upstream region after interacting with a quasi-perpendicular curved shock front. Two different types of simulations have been performed based on (i) a fully consistent expansion (FCE) model, which includes all self-consistent shock profiles at different times, and (ii) a homothetic expansion (HE) model in which shock profiles are fixed at certain times and artificially expanded in space. The comparison of both configurations allows one to analyze the impact of the front nonstationarity on the back-streaming population. Moreover, the role of the space charge electric field El is analyzed by either including or canceling the El component in the simulations. A detailed comparison of these last two different configurations allows one to show that this El component plays a key role in the ion reflection process within the whole quasi-perpendicular propagation range. Simulations provide evidence that the different field-aligned beam (FAB) and gyro-phase bunched (GPB) populations observed in situ are essentially formed by a Et×B drift in the velocity space involving the convective electric field Et. Simultaneously, the study emphasizes (i) the essential action of the magnetic field component on the GPB population (i.e., mirror reflection) and (ii) the leading role of the convective field Et in the FAB energy gain. In addition, the electrostatic field component El is essential for reflecting ions at high θBn angles and, in particular, at the edge of the ion foreshock around 70∘. Moreover, the HE model shows that the rate BI% of back-streaming ions is strongly dependent on the shock front profile, which varies because of the shock front nonstationarity. In particular, reflected ions appear to escape periodically from the shock front as bursts with an occurrence time period associated to the self-reformation of the shock front.

Dynamics of dislocations in a two-dimensional block copolymer system with hexagonal symmetry

2011 ◽  
Vol 369 (1935) ◽  
pp. 335-350 ◽  
Author(s):  
Aldo D. Pezzutti ◽  
Daniel A. Vega ◽  
Marcelo A. Villar
Keyword(s):  
Thin Films ◽  
Block Copolymer ◽  
Topological Defects ◽  
Two Dimensional ◽  
Significant Progress ◽  
Hexagonal Symmetry ◽  
Scale Selection ◽  
Long Range Ordering ◽  
Lithographic Masks

Block copolymer thin films have attracted considerable attention for their ability to self-assemble into nanometre-scale architectures. Recent advances in the use of block copolymer thin films as nano-lithographic masks have driven research efforts in order to have better control of long-range ordering in the plane of the film. Irrespective of the method of sample preparation, different quasi-two-dimensional systems with hexagonal symmetry unavoidably contain translational defects, called dislocations. Dislocations control the process of coarsening in the nano/meso-scales and provide one of the most important mechanisms of length-scale selection in hexagonal patterns. Although in the last decade the nonlinear dynamics of topological defects in quasi-two-dimensional systems has witnessed significant progress, still little is known about the role of external fields on the creation and annihilation mechanisms involved in the relaxation process towards equilibrium states. In this paper, the dynamics of dislocations in non-optimal hexagonal patterns is studied in the framework of the Ohta–Kawasaki model for a diblock copolymer. Measurements of the climb and glide velocities as a function of the wave vector deformation reveal the main mechanisms of relaxation associated with the motion of dislocations.

Microstructure variations induced by excess PbX2or AX within perovskite thin films

2017 ◽  
Vol 53 (96) ◽  
pp. 12966-12969 ◽  
Author(s):  
Guanhaojie Zheng ◽  
Cheng Zhu ◽  
Yihua Chen ◽  
Juchen Zhang ◽  
Qi Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Grazing Incidence ◽  
Stoichiometric Ratio ◽  
Wide Angle ◽  
Two Dimensional ◽  
X Ray ◽  
X Ray Scattering ◽  
Hybrid Perovskite ◽  
Scattering Technique ◽  
The Impact

We investigated the impact of stoichiometric ratio of PbX2/AX on microstructures within hybrid perovskite films, especially on the plane stacking directions, using the two-dimensional synchrotron radiation grazing incidence wide-angle X-ray scattering technique.

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